Process for the trans-selective hydroboration of internal alkynes

Abstract

The present invention refers to a process for the trans-selective hydroboration of internal alkynes and the so-obtained products. The inventive process makes use of a borane of the formula X.sup.1X.sup.2BH selected from the group of dialkyl boranes or di(alkoxy)boranes which are reacted with the internal alkynes in the presence of a cyclyopentadienyl-coordinated ruthenium catalyst.

Claims

1. Process for highly stereoselective trans-hydroboration of internal alkynes comprising the steps of reacting an alkyne of the formula I: ##STR00034## with a borane of the formula X.sup.1X.sup.2BH in the presence of a ruthenium catalyst to yield an alkene of the general formula (II): ##STR00035## wherein: R.sup.1 and R.sup.2 are the same or different and are each be selected from: a. straight chain or branched chain aliphatic hydrocarbons, said aliphatic hydrocarbons optionally including heteroatoms and/or aromatic hydrocarbons and/or heteroaromatic hydrocarbons in the chain and/or having one or more substituents selected from C.sub.1-C.sub.20-alkyl, C.sub.5-C.sub.8-heterocycloalkyl or C.sub.6 to C.sub.20 aromatic hydrocarbon, C.sub.5 to C.sub.20 heteroaromatic hydrocarbon or aryl-(C.sub.1-C.sub.6)-alkyl, heteroaryl-(C.sub.1-C.sub.6)-alkyl, or heteroatoms, or b. aromatic hydrocarbons having 5 to 20 carbon atoms or heteroaromatic hydrocarbons having 1 to 20 carbon atoms, said aromatic or heteroaromatic hydrocarbons each optionally having one or more substituents selected from C.sub.1-C.sub.20-alkyl, C.sub.5-C.sub.8-heterocycloalkyl or C.sub.6 to C.sub.20 aromatic hydrocarbon, C.sub.5 to C.sub.20 heteroaromatic hydrocarbon or aryl-(C.sub.1-C.sub.6)-alkyl, heteroaryl-(C.sub.1-C.sub.6)-alkyl, heteroatoms, or R.sup.1 and R.sup.2 together form an aliphatic hydrocarbon chain having 4 to 30 carbon atoms, optionally including heteroatoms and/or aromatic hydrocarbons in the chain and/or optionally having one or more substituents selected from C.sub.1-C.sub.20-alkyl, C.sub.5-C.sub.8-heterocycloalkyl or C.sub.6 to C.sub.20 aromatic hydrocarbon, C.sub.5 to C.sub.20 heteroaromatic hydrocarbon or aryl-(C.sub.1-C.sub.6)-alkyl, heteroaryl-(C.sub.1-C.sub.6)-alkyl, said aliphatic hydrocarbon chain optionally being substituted by one or more substituents selected from heterosubstituents, straight chain, branched chain, cyclic aliphatic C.sub.1 to C.sub.20 hydrocarbons, C.sub.6 to C.sub.20 aromatic hydrocarbon, C.sub.5 to C.sub.20 heteroaromatic hydrocarbon, aryl-(C.sub.1-C.sub.6)-alkyl, or heteroaryl-(C.sub.1-C.sub.6)-alkyl or heteroatoms; wherein the borane of the formula X.sup.1X.sup.2BH is selected from the group of dialkyl boranes or di(alkoxy)boranes wherein X.sup.1 and X.sup.2 are the same or different and are each selected from straight chain, branched chain or cyclic aliphatic hydrocarbons, or X.sup.1 and X.sup.2 together form an aliphatic hydrocarbon chain having 2 to 20 carbon atoms, said aliphatic hydrocarbon—group or chain—optionally bound to the boron via an —O-bridge and optionally including heteroatoms in the chain and/or optionally having one or more substituents selected from C.sub.1-C.sub.20-alkyl, C.sub.5-C.sub.8-heterocycloalkyl or C.sub.6 to C.sub.20 aromatic hydrocarbon, C.sub.1 to C.sub.20 heteroaromatic hydrocarbon or aryl-(C.sub.1-C.sub.6)-alkyl, heteroaryl-(C.sub.1-C.sub.6)-alkyl, having identical or different alkyl groups with 2 to 12 carbon atoms or heteroatoms; and wherein the catalyst used in the inventive process is a cyclyopentadienyl-coordinated ruthenium complex containing the following substructure: ##STR00036## wherein R.sub.cp1 to R.sub.cp5 are the same or different and are each selected from hydrogen or from straight chain, branched chain or cyclic aliphatic hydrocarbons, optionally including heteroatoms and/or aromatic hydrocarbons in the chain and/or optionally having one or more substituents selected from C.sub.1-C.sub.20-alkyl, heterocycloalkyl, C.sub.5 to C.sub.20 aromatic hydrocarbon, C.sub.5 to C.sub.20 heteroaromatic hydrocarbon or aryl-(C.sub.1-C.sub.6)-alkyl, heteroaryl-(C.sub.1-C.sub.6)-alkyl or heteroatoms and wherein further ligands L are coordinated to the central atom ruthenium.

2. Process for highly stereoselective trans-hydroboration of internal alkynes according to claim 1 wherein, in formulas (I) and (II): R.sup.1 and R.sup.2 are the same or different and are each selected from straight chain or branched chain aliphatic hydrocarbons having 1 to 20 carbon atoms optionally including heteroatoms and/or aromatic hydrocarbons in the chain or aromatic hydrocarbons having 5 to 20 carbon atoms, optionally having one or more substituents selected from C.sub.1-C.sub.20-alkyl, C.sub.5-C.sub.8-heterocycloalkyl or C.sub.6 to C.sub.20 aromatic hydrocarbon, C.sub.5 to C.sub.20 heteroaromatic hydrocarbon or aryl-(C.sub.1-C.sub.6)-alkyl, heteroaryl-(C.sub.1-C.sub.6)-alkyl, or heteroatoms, or R.sup.1 and R.sup.2 together form an aliphatic hydrocarbon chain structure having 8 to 20 carbon atoms, optionally including heteroatoms and/or aromatic hydrocarbons in the chain and/or optionally having one or more substituents selected from C.sub.1-C.sub.20-alkyl, C.sub.5-C.sub.8-heterocycloalkyl or C.sub.6 to C.sub.20 aromatic hydrocarbon, C.sub.5 to C.sub.20 heteroaromatic hydrocarbon or aryl-(C.sub.1-C.sub.6)-alkyl, heteroaryl-(C.sub.1-C.sub.6)-alkyl, said chain structure optionally being substituted by one or more substituents selected from heterosubstituents, straight chain, branched chain, cyclic aliphatic C.sub.1 to C.sub.20 hydrocarbons, C.sub.6 to C.sub.20 aromatic hydrocarbon, C.sub.5 to C.sub.20 heteroaromatic hydrocarbon, aryl-(C.sub.1-C.sub.6)-alkyl, or heteroaryl-(C.sub.1-C.sub.6)-alkyl.

3. Process for highly stereoselective trans-hydroboration of internal alkynes according to claim 1, wherein, in the formula X.sup.1X.sup.2BH, X.sup.1 and X.sup.2 are each bound to the boron atom via an —O-bridge and form a hydrocarbon ring having 2 to 12 carbon atoms, said hydrocarbon ring optionally being substituted by one or more substituents selected from heterosubstituents, C.sub.1 to C.sub.6 straight chain, branched chain or cyclic aliphatic hydrocarbons, as represented by the general formula (III): ##STR00037##

4. Process for highly stereoselective trans-hydroboration of internal alkynes according to claim 3 wherein, in the formula X.sup.1X.sup.2BH, X.sup.1 and X.sup.2 are each bound to the boron atom via an —O-bridge and form a hydrocarbon ring having 2 to 12 carbon atoms, said hydrocarbon ring, optionally being substituted by one or more substituents selected from hydrogen, methyl, ethyl, propyl, butyl or isomers thereof.

5. Process for highly stereoselective trans-hydroboration of internal alkynes according to claim 1, wherein pinacolborane (pin-H, 4,4,5,5-tetramethyl-1,3,2-dioxaborolane) is used as boran of the formula X.sup.1X.sup.2BH: ##STR00038##

6. Process for highly stereoselective trans-hydroboration of internal alkynes according to claim 1, wherein 4,4,6-trimethyl-1,3,2-dioxaborinane is used as borane of the formula X.sup.1X.sup.2BH: ##STR00039##

7. Process for highly stereoselective trans-hydroboration of internal alkynes according to claim 1, wherein the catalyst is [Cp*RuL.sub.3]X wherein Cp*=η.sup.5-C.sub.5R.sub.5cp with each R.sub.cp being H or lower alkyl, and L being the same or different ligand/substituent and being selected from electron-donating ligands/substituents, and X is an anionic counter ion.

8. Process for highly stereoselective trans-hydroboration of internal alkynes according to claim 1, wherein the following complex is used as catalyst: ##STR00040## wherein the substituent R is selected from R═H, Me and X.sup.⊖ is an anionic counter ion.

9. Process for highly stereoselective trans-hydroboration of internal alkynes according to claim 7, wherein the anionic counterion is selected from PF.sub.6.sup.−, SbF.sub.6.sup.−, BF.sub.4.sup.−, ClO.sub.4.sup.−, F.sub.3CCOO.sup.−, Tf.sub.2N.sup.−, (Tf=trifluoromethanesulfonyl), TfO.sup.−, tosyl, [B[3,5-(CF.sub.3).sub.2C.sub.6H.sub.3].sub.4].sup.−, B(C.sub.6F.sub.5).sub.4.sup.− or Al(OC(CF.sub.3).sub.3).sub.4.

10. Process for highly stereoselective trans-hydroboration of internal alkynes according to claim 1, wherein the catalyst is selected from the following complexes: ##STR00041## wherein the substituent X is selected from Cl, Br, I.

11. Method of using a ruthenium catalyst comprising a cyclyopentadienyl-coordinated ruthenium complex containing the following substructure: ##STR00042## wherein R.sub.cp1 to R.sub.cp5 are the same or different and are each selected from hydrogen or from straight chain, branched chain or cyclic aliphatic hydrocarbons, optionally including heteroatoms and/or aromatic hydrocarbons in the chain and/or optionally having one or more substituents selected from C.sub.1-C.sub.20-alkyl, heterocycloalkyl, C.sub.5 to C.sub.20 aromatic hydrocarbon, C.sub.5 to C.sub.20 heteroaromatic hydrocarbon or aryl-(C.sub.1-C.sub.6)-alkyl, heteroaryl-(C.sub.1-C.sub.6)-alkyl or heteroatoms and wherein further ligands L are coordinated to the central atom ruthenium, in a hydroboration reaction in the presence of an organic boron compound.

Description

(1) The invention is further illustrated by the attached drawings, wherein:

(2) FIG. 1 illustrates the conventional hydroboration of alkynes (top) occurring via a four-center transition state A under frontier orbital control. In the essence, the HOMO of the alkyne donates electron density into a empty boron-centered π-orbital, while electron density is simultaneously back-donated from the bonding B—H σ-orbital into the LUMO of the alkyne. As a consequence of this concerted process, hydrogen and boron are added in a cis-fashion to the triple bond. The trans-addition mode engendered by cationic ruthenium complexes of type C described herein (center) stands in marked contrast to this established stereochemical pattern. The only other widely applicable formal trans-hydroboration known in the literature (bottom) is limited to terminal alkynes. However, it is not a regular 1,2-addition process but proceeds via an initial isomerization with formation of a metal vinylidene intermediate (B). As a consequence, it is the H-atom of the alkyne itself rather than the H-atom of the reagent that ends up trans to the boron entity;

(3) FIG. 2 gives an overview over the substrate scope, functional group tolerance and stereoselectivity of the ruthenium catalyzed trans-hydroboration. Unless stated otherwise, all reactions were performed at ambient temperature in CH.sub.2Cl.sub.2 (1 M) under argon using 5 mol % of [Cp*Ru(MeCN).sub.3]PF.sub.6 as the catalyst; depending on the substrates, the reaction times varied between 30 min and 20 h, except for the thiophene derivative, which took 72 h to reach full conversion. Panel A: products derived from symmetrical alkynes; panel B: products derived from unsymmetrical alkynes; only one isomer is depicted (the data in brackets show the isomer ratio (GC) in the crude material, with the depicted isomer in bold); panel C: products with less reactivity in the inventive process;

(4) FIG. 3 illustrates a possible scenario as sketched by the inventors that explains the course of the trans-hydroboration reaction and encompasses the currently available mechanistic information; and,

(5) FIG. 4 illustrates the preparation of a di- and trisubstituted E-cycloalkene by derivatization of E-2 as explained below.

(6) The inventors have carried out an initial screening of catalysts and boranes for the trans-hydroboration of internal alkynes. The results are indicated in the following Table 1.

(7) TABLE-US-00001 TABLE 1 Initial screening of catalysts and boranes for the trans-hydroboration of internal alkynes. Entry Borane [Ru] E:Z Yield (%) 1 9-H-BBN 3 — — .sup.[a] 2 cat-H 3  1.2:1 <20 (GC) .sup.[b] 3 pin-H 4  75:25   84 4 pin-H 3 ≧98:2   95 5 pin-H 3 ≧98:2   88 .sup.[c] 6 pin-D.sup.[d] 3 ≧98:2   88 .sup.[d] 7 pin-H 5 + AgOTf .sup.[e] ≧98:2   71 pin-H 5 ≧98:2   44 (GC) .sup.[b] 9 pin-H 7 ≧98:2   67 10 pin-H 6  95:5   15 (GC) .sup.[b] 11 pin-H 8  98:2   24 (GC) .sup.[b] .sup.[a] mixture; .sup.[b] conversion rather than isolated yield; .sup.[c] the reaction was performed in the dark; .sup.[d] the deuterium content in the reagent was ≈ 95%, in the product ≈ 93% (NMR); .sup.[e] complex 5 was ionized on addition of AgOTf (5 mol %) prior to the addition of borane and substrate.

(8) The reactions as indicated in Table 1 were carried out at 1 M concentration in CH.sub.2Cl.sub.2 under argon. The E:Z ratios were determined by GC and refer to the crude material prior to work up. Unless stated otherwise, the yields refer to analytically pure isolated material.

(9) Thus, the reaction of cycloalkyne 1 with 9-H—BBN dimer in the presence of [Cp*Ru(MeCN).sub.3]PF.sub.6 (3) (5 mol %) as precatalyst gave a product mixture (entry 1). The use of catecholborane (cat-H)—despite the excellent track record of this reagent in metal catalyzed hydroborations—resulted in low conversion (<20%, GC) and an isomer ratio (E:Z=1.2:1) (entry 2).

(10) Although catecholborane and pinacolborane exhibit comparable reactivity in uncatalyzed hydroboration reactions, the inventors have found that they perform markedly different in the presence of [Cp*Ru(MeCN).sub.3]PF.sub.6 (3). Thus, addition of 5 mol % of this complex to a solution of 1 and pin-H in CH.sub.2Cl.sub.2 resulted in a very fast (<10 min), clean and exquisitely trans-selective hydroboration (E:Z≧98:2, GC) (entry 4). On a 5 mmol scale, product E-2 was isolated in 91% yield using only 3 mol % of the ruthenium catalyst. When the loading was further reduced to 1 mol %, the reaction still proceeded smoothly, reaching ≧95% conversion within 3 h at ambient temperature. Importantly, GC-monitoring showed that the E/Z-ratio was consistently high throughout the entire course of the reaction. The same excellent E-selectivity was recorded when the hydroboration was performed in the dark, which excludes that the trans-alkenylborane product is formed by a secondary photochemical Z.fwdarw.E isomerization (entry 5). Likewise, authentic Z-2 remained unchanged when exposed to catalytic amounts of complex 3 in CH.sub.2Cl.sub.2. As an additional control experiment, deuterated pinacolborane (pin-D, ≈95% D) was used to rule out that the hydrogen atom residing trans to the boronate unit in the product derives from any other hydrogen source than the chosen borane reagent (≈93% deuterium incorporation, NMR) (entry 6). Collectively, these data suggest that the observed trans-addition is an inherent feature of the new methodology, and that the reaction is a true hydroboration rather than an isomerization process.

(11) In analogy to pinacol borane, other heterocyclic borane reagents can also be used for the present trans-addition reaction. As a representative example, the following reaction scheme illustrates the use of 4,4,6-trimethyl-1,3,2-dioxaborinane

(12) ##STR00007##

(13) Since all other metal-catalyzed hydroborations of internal alkynes follow the traditional syn-addition mode, utmost care was taken to confirm the unusual stereochemical outcome of the new procedure. The trans-configuration of product E-2 is evident from its spectroscopic data and was confirmed by comparison (GC, NMR) with an authentic sample of Z-2 made by conventional hydroboration of 1. Furthermore, single crystals suitable for X-ray diffraction analysis could be grown (see insert in Table 1); the structure of E-2 in the solid state unambiguously confirms the constitution and configuration of this product.

(14) A brief survey showed that the use of [Cp*Ru(MeCN).sub.3]PF.sub.6 (3) in CH.sub.2Cl.sub.2 is a preferred catalyst. Full conversion could also be reached in THF, whereas 1,4-dioxane as cosolvent caused a rate-deceleration and toluene basically halted the conversion (<10%, GC). This result is thought to reflect the affinity of [LRu(MeCN).sub.3].sup.+ (L=Cp, Cp*) towards arenes (and other conjugated π-systems), which leads to the formation of kinetically fairly stable adducts of type [Cp*Ru(ηq.sup.6-arene)].sup.+. The inventors assume that a similar interaction explains why catecholborane with its electron rich arene ring is less effective than the purely aliphatic pinacolborane as the reagent in the present trans-addition, whereas these reagents show only gradually different reactivity vis-à-vis alkynes otherwise.

(15) Formal replacement of the labile MeCN ligands on the cationic [Cp*Ru].sup.+ template by a kinetically more tightly bound cyclooctadiene (cod) moiety allows the reaction still to proceed but makes it somewhat less productive. Whereas the cationic species [Cp*Ru(cod)]OTf gave a respectable yield of 71% (Table 1, entry 7), the neutral variant [Cp*Ru(cod)Cl] (5) furnished no more than 44% conversion (GC) after 1 h (entry 8). In this case, the borane reagent itself may help release a cationic species in solution by slow abstraction of the chloride from the ruthenium precatalyst. A similar process might account for the activation of the chloride-bridged complex 7 (entry 9). Although the tested precatalysts greatly differ in efficiency, the E/Z-ratio was high in all cases, which may indicate the formation of a (largely) common active species. Moreover, it is unlikely that the actual catalyst is an ordinary ruthenium hydride, since complexes 6 and 8 comprising a preformed Ru—H bond gave rather poor results (entries 10, 11).

(16) Of mechanistic significance is the observation of the inventors that the exquisite trans-selectivity is compromised upon formal replacement of the Cp* unit by the parent unsubstituted cyclopentadienyl (Cp) ring present in [CpRu(MeCN).sub.3]PF.sub.6 (4), although the trans-addition product is still formed as the major compound (entry 3 versus entry 4). Since this structural change hardly affects the electronic properties of the ruthenium center, the stereo determining step of the catalytic cycle likely has a large steric component. A possible rationale is outlined below.

(17) Next, the optimal reaction conditions were applied to a set of representative alkyne derivatives to explore the scope and limitations of the new procedure. As can be seen from the results compiled in FIG. 2, good to outstanding trans-selectivity was observed for a variety of substrates and the chemical yields were also good to excellent (panels A and B). In close analogy to the uncatalyzed hydroboration (Brown, H. C. Hydroboration. W. A. Benjamin, Inc., New York, 1962; Pelter, A., Smith, K. & Brown, H. C. Borane Reagents. Academic Press, London 1988), unsymmetrical alkynes lead to the formation of regioisomers, with a certain preference to place the boronate residue away from the bulkier substituent (panel B); careful NMR analysis confirmed that either regioisomer comprises an E-olefin subunit.

(18) Most importantly, a variety of functional groups in the reaction system is tolerated, including ethers, esters, carbamates, acetals, nitriles, aryl and alkyl halides, and a primary alkyl tosylate. Even readily reducible sites such as a ketone, a nitro group, or the N—O bond of a Weinreb amide remained intact. Equally remarkable is the fact that an internal acetylene could be selectively hydroborated in the presence of a terminal olefin; the obvious “alkynophilicity” of the catalyst has mechanistic implications, too. Thus, the skilled man can easily test the matching conditions for the alkyne, ruthenium catalyst and borane.

(19) The known affinity of [Cp*Ru] to arenes explains why tolane hardly reacts under the above conditions (panel C), but modifying the reactions conditions including testing different Ru-catalysts and boranes should enable the skilled man to find out suitable conditions. The inventors assume that electron withdrawing substituents on the aromatic ring might destabilize sandwich complexes of the general type [Cp*Ru(η.sup.6-arene)].sup.+ (Gill, T. P. et al., Organometallics 1, 485-488 (1982); Schmid, A. et al., Eur. J. Inorg. Chem. 2255-2263 (2003)). In fact, arylalkynes bearing electron withdrawing groups (—CF.sub.3, —COOMe) on the aromatic ring reacted well, although they took longer to reach full conversion. Particularly noteworthy in this context is the successful trans-hydroboration of sulfur-containing substrates. Though electron rich, the thiophilicity of ruthenium outweighs 7-complex formation and seems to direct the catalyst towards the triple bond. In any case, the compatibility of an unhindered thioether or a thiophene unit with a reaction catalyzed by a soft transition metal species is quite remarkable.

(20) Despite this significant scope and functional group tolerance, a few limitations of the new trans-hydroboration reaction were noticed. Whereas the 14-membered cycloalkyne 1 reacted with exquisite E-selectivity (E:Z≧98:2), its 12-membered homologue gave an isomer mixture (E:Z=75:25, see panel A), and cyclooctyne was merely polymerized (panel C). This trend is ascribed to ring strain, which strongly disfavors E-configured cycloalkenes over the corresponding Z-isomers as the ring size decreases. Another limitation was encountered with terminal alkynes, which failed to react under standard conditions.

(21) Although it is premature at this stage to draw a conclusive mechanistic picture, the basic features of the trans-selective hydroboration can be rationalized as follows. NMR inspection of a 1:1 mixture of pinacolborane and [Cp*Ru(MeCN).sub.3]PF.sub.6 (3) in CD.sub.2Cl.sub.2 in the absence of an alkyne substrate showed no signs of chemical reaction or strong interaction of the partners; in any case, distinct metal boryl or metal hydride complexes could not be observed. This result is in line with the screening data that had shown the poor performance of preformed ruthenium hydride complexes in the present reaction. On the other hand, alkynes are known to readily engage with complexes of the general type [LRu].sup.+ (L=Cp, Cp*), leading to the coupling of two substrate molecules via ruthenacyclic intermediates (Trost, B. M. et al., Angew. Chem. Int. Ed. 44, 6630-6666 (2005)). This smooth C—C-bond formation is obviously outperformed by the trans-hydroboration presented herein.

(22) The inventors assume that binding of an alkyne to the electrophilic metal center of C subsequently favors coordination of the borane rather than of a second alkyne on electronic grounds (FIG. 3). In the resulting loaded complex E, the acetylene moiety is supposed to function as a four-electron donor, which explains why alkenes do not react under the chosen conditions. This bonding situation, in turn, facilitates an inner-sphere nucleophilic delivery of the hydride with formation of a metallacyclopropene F (η.sup.2-vinyl complex) without prior generation of a discrete Ru—H species. It is very well precedented that the substituents at the β-carbon atom of such complexes are configurationally labile and can easily swap places via a η.sup.2.fwdarw.η.sup.1.fwdarw.η.sup.2 hapticity change (Frohnapfel, D. S. et al., Coord. Chem. Rev. 206-207, 199-235 (2000)). As they are approximately orthogonal to the plane of the metallacyclopropene, the sheer size of the Cp* ring will exert a massive influence on the stereochemical outcome. As a consequence, isomer H, in which the hydrogen rather than the R group is oriented towards the bulky lid, will be largely favored over F. This decisive steric factor loses weight if the lateral methyl groups of the Cp* ring are formally removed and [CpRu]-based catalysts are used. The trajectory of the ensuing reductive elimination places the boron entity anti to the hydrogen atom and hence leads to the formation of an E-configured alkenylboronate product.

(23) Of the countless possible derivatizations of the E-alkenylboronates made available by this convenient new procedure, the inventors explored the protodeborylation of E-2 with AgF in aqueous medium as well as an equally stereo-retentive Suzuki coupling with methyl iodide (FIG. 4). Both reactions led, without any detectable loss of stereochemical integrity, to E-configured cycloalkenes.

(24) Thus, by the present invention, the inventors have shown that simple ruthenium catalysts, most notably the commercially available complex [Cp*Ru(MeCN).sub.3]PF.sub.6 (Cp*=η.sup.5-C.sub.5Me.sub.5), allow the fundamental and largely unchallenged rule of suprafacial delivery of hydrogen and boron to the same Tr-face of a given starting material (cis-additon mode) to be broken for internal alkynes as the substrates. The searching of libraries of matching candidates of alkyne, ruthenium catalyst and borane provides the simple means of finding the best system for a given transition Ru-catalyzed conversion. This procedure is simple and can be performed rapidly by standard laboratory techniques or, alternatively, with modern instruments which are customary in combinatorial catalysis. The resulting trans-selective hydroboration opens a practical new entry into E-configured alkenylboron derivatives which could previously only be made by indirect routes. The inventors expect this stereo-complementary methodology to add another dimension to the uniquely prolific field of organoboron chemistry. The inventive alkenylboron derivatives can be used for further synthesis of, for example, drug compounds or drug candidates, natural products, fine chemicals, agrochemicals, polymers, liquid crystals, fragrances, flavors, cosmetic ingredients, sun protective agents. Furthermore, they can be used for the preparation of compound libraries by combinatorial or parallel synthesis.

(25) The invention is further illustrated by the general method for trans-hydroboration as shown in Example 1 and further exemplified in the subsequent Examples 2 to 26 for various products of the trans-hydroboration of internal alkynes.

EXAMPLE 1

(E)-11-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-1,8-dioxacyclotetradec-11-ene-2,7-dione (E-2)

(26) ##STR00008##

(27) A flame-dried 10 mL Schlenk tube was charged under Ar with [Cp*Ru(CH.sub.3CN).sub.3]PF.sub.6 (75.6 mg, 0.15 mmol) and CH.sub.2Cl.sub.2 (5 mL) and the resulting solution was cooled to 0° C. with an ice bath. Pinacolborane (872 μL, 6 mmol) and alkyne 1 (1.12 g, 5 mmol) were successively added, the ice bath was removed and the solution stirred for 4 h at ambient temperature. For workup, the solvent was evaporated and the residue passed through a short column of silica, eluting with EtOAc/hexanes (1/4), to give alkenylboronate E-2 as a white crystalline solid (1.61 g, 91%, E/Z≧98:2). When the same reaction performed at 0.2 mmol scale, the product was isolated in 96% yield. Mp=66.7-70.4° C.; .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 6.06 (1H, t, J=7.0 Hz), 4.18 (2H, t, J=5.5 Hz), 4.12 (2H, t, J=5.5 Hz), 2.71 (2H, dt, J=5.5, 7.1 Hz), 2.41 (2H, t, J=5.0 Hz), 2.34-2.24 (4H, m), 1.65-1.55 (4H, m), 1.22 (s, 12H); .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 173.2, 173.1, 145.8, 83.0, 64.2, 63.2, 36.1, 34.9, 34.8, 30.0, 24.7, 24.5, 24.5 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.6; IR (thin film): 2965, 1720, 1644, 1265, 1134, 861, 708 cm.sup.−1, HRMS (ESI): m/z calcd for C.sub.18H.sub.29BO.sub.6Na [M.sup.++Na]: 375.1947. found: 375.1949.

EXAMPLE 2

12-(H2)-(E)-11-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-1,8-dioxacyclotetradec-11-ene-2,7-dione [D]-E-2

(28) ##STR00009##

(29) White solid (62 mg, 88%); .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 4.19 (2H, t, J=5.3 Hz), 4.13 (2H, t, J=5.5 Hz), 2.71 (2H, t, J=5.4 Hz), 2.42 (2H, t, J=5.3 Hz), 2.35-2.23 (4H, m), 1.66-1.54 (4H, m), 1.23 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 173.0, 172.8, 145.2 (t, J=23.42 Hz), 82.7, 64.0, 63.0, 35.8, 34.6, 34.5, 29.6, 24.4, 24.3, 24.2 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.2H NMR (CH.sub.2Cl.sub.2, 92 MHz, 22° C.): δ 6.1, .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.6; HRMS (ESI): m/z calcd for C.sub.18H.sub.28BO.sub.6DNa [M.sup.++Na]: 376.2010. found: 376.2012.

EXAMPLE 3

(E)-2-(Dec-5-en-5-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

(30) ##STR00010##

(31) Colorless oil (237 mg, 89%); reaction time=1 h; .sup.1H NMR (CDCl.sub.3, 300 MHz): δ=5.97 (1H, t, J=7.5 Hz), 2.29 (2H, q, J=7.1, 14.2 Hz), 2.07 (2H, t, J=6.9 Hz), 1.40-1.28 (m, 8H), 1.25 (12H, s), 0.93-0.81 (6H, m); .sup.13C NMR (CDCl.sub.3, 75 MHz): δ 146.4, 83.0, 37.0, 33.0, 32.7, 31.2, 25.1, 22.7, 22.6, 14.4, 14.3 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 96 MHz): δ 30.6; HRMS (ESI): m/z calcd for C.sub.16H.sub.31BO.sub.2Na [M.sup.++Na]: 289.2322. found: 289.2322.

EXAMPLE 4

(E)-3-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)hex-3-ene-1,6-diylbis(4-chlorobenzoate)

(32) ##STR00011##

(33) White solid (73 mg, 94%); reaction time=140 min, .sup.1H NMR (CDCl.sub.3, 300 MHz): δ 7.97-7.86 (4H, m), 7.40-7.29 (4H, m), 6.24 (1H, t, J=7.5 Hz), 4.40-4.26 (4H, m), 2.83 (2H, q, J=6.4, 13.6 Hz), 2.57 (2H, t, J=6.6 Hz), 1.24 (12H, 5), .sup.13C NMR (CDCl.sub.3, 75 MHz): δ 165.60, 165.55, 144.9, 139.2, 139.1, 130.9, 130.8, 129.0, 128.9, 128.53, 128.52, 83.2, 65.0, 64.8, 36.1, 30.6, 24.7 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.7; HRMS (ESI): m/z calcd for C.sub.26H.sub.29BCl.sub.2O.sub.6Na [M.sup.++Na]: 541.1338. found: 541.1338.

EXAMPLE 5

(E)-3-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)hex-3-ene-1,6-diyl bis(4-methoxybenzoate)

(34) ##STR00012##

(35) Colorless oil (40 mg, 75%); reaction time=1 h; .sup.1H NMR (CDCl.sub.3, 400 MHz): δ=7.89 (2H, d, J=3.5 Hz), 7.87 (2H, d, J=3.5 Hz), 6.87 (2H, d, J=8.8 Hz), 6.84 (2H, d, J=8.8 Hz), 6.28 (1H, t, J=7.3 Hz), 4.36-4.25 (4H, m), 3.84 (3H, s), 3.82 (3H, s), 2.83 (2H, q, J=6.8, 13.6 Hz), 2.56 (2H, t, J=6.6 Hz), 1.24 (12H, 5), .sup.13C NMR (CDCl.sub.3, 75 MHz): δ 166.30, 166.25, 163.2, 163.1, 145.1, 131.54, 131.45, 123.1, 123.0, 113.47, 113.45, 83.2, 64.5, 64.4, 55.32, 55.31, 36.2, 30.8, 24.8 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 29.7; HRMS (ESI): m/z calcd for C28H35BO.sub.8Na [M.sup.++Na]: 533.2330. found: 533.2333.

EXAMPLE 6

(E)-29-Nitro-13-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4,5,6,7,8,9,10,11,12,15,16,17,18,19,20,21,22,23,24-icosahydrobenzo[c][1,6]dioxacyclooctacosine-1,26-dione

(36) ##STR00013##

(37) White solid (48 mg, 77%); reaction time=4 h; .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 8.60 (1H, d, J=2.27 Hz), 8.37 (1H, 2d, J=2.2 Hz), 7.84 (1H, d, J=8.3 Hz), 5.93 (1H, t, J=7.4 Hz), 4.40-4.26 (4H, m), 2.33 (2H, q, J=6.5, 13.3 Hz), 2.09 (2H, t, J=6.3 Hz), 1.82-1.67 (4H, q, J=7.0, 14.1 Hz), 1.46-1.13 (40H, m); .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 166.3, 165.2, 148.7, 147.1, 138.2, 133.2, 130.1, 125.8, 124.4, 82.6, 66.6, 36.2, 30.49, 30.47, 29.6, 29.5, 29.4, 29.32, 29.28, 29.2, 28.5, 28.43, 28.39, 28.37, 28.26, 28.21, 28.04, 27.96, 25.70, 25.65, 24.8 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 31.0; HRMS (ESI): m/z calcd for C.sub.36H.sub.56BNO.sub.8Na [M.sup.++Na]: 664.4007. found: 664.4009.

EXAMPLE 7

(E)-2-(1,6-Bis(benzyloxy)hex-3-en-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

(38) ##STR00014##

(39) Colorless oil, (65 mg, 83%); reaction time=2 h 30 min, .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 7.34-7.12 (10H, m), 6.09 (1H, t, J=7.3 Hz), 4.44 (2H, s), 4.42 (2H, s), 3.41 (4H, q, J=7.0, 15.0 Hz), 2.61 (2H, q, J=7.10, 14.2 Hz), 2.36 (2H, t, J=7.1 Hz), 1.14 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 144.3, 143.3, 138.8, 138.6, 128.3, 128.2, 127.6, 127.4, 127.3, 82.9, 72.6 (2C), 70.7, 70.2, 37.1, 31.6, 24.7 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.9; HRMS (ESI): m/z calcd for C.sub.26H.sub.35BO.sub.4Na [M.sup.++Na]: 445.2532. found: 445.2536.

EXAMPLE 8

(E)-3-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)hex-3-ene-1,6-diylbis(4-methylbenzene-sulfonate)

(40) ##STR00015##

(41) Colorless oil (40 mg, 73%); reaction time=2 h 30 min, .sup.1H NMR (CDCl.sub.3, 300 MHz): δ=7.82-7.72 (4H, m), 7.38-7.28 (4H, m), 5.92 (1H, t, J=7.3 Hz), 4.06-3.93 (4H, m), 2.68 (2H, q, J=6.8, 13.9 Hz), 2.44 (3H, s), 2.43 (3H, s), 2.35 (2H, t, J=6.8 Hz), 1.16 (12H, 5), .sup.13C NMR (CDCl.sub.3, 75 MHz): δ 144.6, 144.5, 144.0, 133.4, 133.2, 129.8, 129.7, 127.9 (2C), 83.3, 70.2, 70.0, 36.2, 30.5, 24.7, 21.56, 21.55 (the C-atom directly attached to boron is broadened and could not be precisely localized); HRMS (ESI): m/z calcd for C.sub.26H.sub.35BO.sub.8Na [M.sup.++Na]: 573.1770. found: 573.1773.

EXAMPLE 9

(E)-2-(1,6-Bis((tetrahydro-2H-pyran-2-yl)oxy)hex-3-en-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxa borolane

(42) ##STR00016##

(43) Colorless oil (42 mg, 61%); reaction time=2 h; .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 6.16 (1H, t, J=7.5 Hz), 4.62-4.55 (2H, m), 3.92-3.80 (2H, m), 3.77-3.64 (2H, m), 3.52-3.35 (4H, m), 2.71-2.57 (2H, m), 2.39 (2H, t, J=7.4 Hz), 1.91-1.75 (2H, m), 1.74-1.62 (2H, m), 1.62-1.42 (8H, m), 1.24 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 144.8, 98.4 (2C), 82.9, 67.7, 67.3, 62.1, 62.0, 37.0, 31.6, 30.7 (2C), 25.5 (2C), 24.8, 19.5 (2C) (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.7; HRMS (ESI): m/z calcd for C.sub.26H.sub.39BO.sub.6Na [M.sup.++Na]: 433.2734. found: 433.2731.

EXAMPLE 10

(E)-3,3′-((13-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)hexacos-13-ene-1,26-diyl)bis(oxy))-dibenzonitrile

(44) ##STR00017##

(45) White solid (53 mg, 87%); reaction time=4 h; .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 7.47-7.30 (3H, m), 7.24-7.18 (2H, m), 7.12 (3H, m), 5.97 (1H, t, J=7.3 Hz), 3.95 (4H, t, J=6.5 Hz), 2.28 (2H, q, J=6.8 Hz), 2.13 (1H, t, J=6.0 Hz), 2.06 (2H, t, J=6.9 Hz), 1.85-1.73 (4H, m), 1.51-1.39 (6H, m), 1.39-1.20 (41H, m); .sup.13C NMR (CDCl.sub.3, 150 MHz): δ 159.1, 145.9, 135.2, 134.9, 130.2, 130.0, 127.9, 124.2, 119.8, 118.8, 117.3, 113.1, 82.9, 80.2, 68.4, 53.4, 36.9, 31.1, 30.3, 30.14, 30.04, 29.62, 29.60, 29.58, 29.56, 29.55, 29.51, 29.46, 29.29, 29.24, 29.14, 29.13, 29.0, 28.8, 28.5, 25.9, 24.8, 18.7 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 77 MHz): δ 31.0, HRMS (ESI): m/z calcd for C.sub.46H.sub.69BN.sub.2O.sub.4Na [M.sup.++Na]: 747.5264. found: 747.5261.

EXAMPLE 11

(E)-Di-tert-butyl(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)dec-5-ene-1,10-diyl)bis(benzyl carbamate)

(46) ##STR00018##

(47) Colorless oil (87 mg, 82%); reaction time=23 h; .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 7.28-7.08 (10H, m), 5.85 (1H, t, J=7.4 Hz), 4.43-4.25 (4H, m), 3.22-2.94 (4H, m), 2.20 (2H, q, J=7.3, 14.6 Hz), 1.97 (2H, t, J=7.3 Hz), 1.53-1.27 (22H, m), 1.26-1.16 (4H, m), 1.15 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 155.8, 155.3, 145.7, 138.3, 132.5, 128.1 (3C), 127.3, 126.7, 115.1, 82.7, 79.1 (2C), 50.0, 49.6, 46.2, 36.3, 36.2, 30.4, 28.1, 27.1 (2C), 27.0, 24.44, 24.39, 24.2 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 96 MHz): δ 31.1; HRMS (ESI): m/z calcd for C.sub.40H.sub.61BN.sub.2O.sub.6Na [M.sup.++Na]: 699.4521. found: 699.4514.

EXAMPLE 12

(E)-N1,N8-Dimethoxy-N1,N8-dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)oct-4-ene-diamide

(48) ##STR00019##

(49) Colorless oil (39 mg, 85%); reaction time=5 h; .sup.1H NMR (CDCl.sub.3, 300 MHz): δ 6.09 (1H, t, J=7.3 Hz), 3.65 (3H, s), 3.64 (3H, s), 3.15 (3H, s), 3.14 (3H, s), 2.61 (2H, q, J=7.2, 14.8 Hz), 2.54-2.31 (6H, m), 1.24 (12H, 5), .sup.13C NMR (CDCl.sub.3, 75 MHz): δ 174.4 (2C), 145.7, 83.0, 61.1 (2C), 32.7, 32.3, 32.2 (2C), 26.28, 26.25, 24.8 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 96 MHz): δ 29.6; HRMS (ESI): m/z calcd for C.sub.18H.sub.33BN.sub.2O.sub.6Na [M.sup.++Na]: 407.2331. found: 407.2337.

EXAMPLE 13

(E)-2-(1,12-Dibromododec-6-en-6-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

(50) ##STR00020##

(51) Colorless oil, (77 mg, 85%); reaction time=4 h; .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 5.97 (1H, t, J=7.5 Hz), 3.39 (4H, t, J=6.9 Hz), 2.31 (2H, q, J=7.4, 14.5 Hz), 2.07 (2H, t, J=6.7 Hz), 1.92-1.78 (4H, m), 1.48-1.31 (8H, m), 1.26 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 146.0, 82.8, 36.5, 34.0, 33.9, 32.7, 32.6, 30.7, 29.3, 28.9, 27.7, 27.5, 24.8 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 31.1; HRMS (ESI): m/z calcd for C.sub.18H.sub.33BBr.sub.2O.sub.2Na [M.sup.++Na]: 473.0842. found: 473.0832.

EXAMPLE 14

(E)-9-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-1,6-dioxacyclododec-9-ene-2,5-dione

(52) ##STR00021##

(53) White solid (27 mg, 54%); reaction time=20 min, .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 5.95 (1H, t, J=6.4 Hz), 4.36-4.21 (4H, m), 2.75 (2H, q, J=6.1, 13.0 Hz), 2.55 (4H, m), 2.40 (2H, t, J=5.6 Hz), 1.27 (12H, s); .sup.13C NMR (CDCl.sub.3, 75 MHz): δ 171.84, 171.83, 146.0, 83.0, 62.78, 62.76, 37.5, 30.6, 30.3, 30.2, 24.8 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): 30.4; HRMS (ESI): m/z calcd for C.sub.16H.sub.25B.sub.1O.sub.6Na [M.sup.++Na]: 347.1633. found: 347.1636.

EXAMPLE 15

1,1′-((E)-2-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)but-2-ene-1,4-diyl)bis(hexahydro-1H-inden-2(3H)-one)

(54) ##STR00022##

(55) Colorless oil (52 mg, 75%); reaction time=20 h; .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 6.00 (1H, t, J=8.0 Hz), 2.74-2.61 (1H, m), 2.60-2.50 (2H, m), 2.30 (2H, ddd, J=6.5 Hz), 2.16-1.88 (6H, m), 1.87-1.70 (9H, m), 1.58-1.22 (6H, m), 1.18 (12H, s), 1.13-0.98 (4H, m); .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 219.3, 219.2, 145.4, 82.9, 55.6, 55.5, 48.9, 48.5, 48.2, 44.9, 44.6, 41.7, 41.5, 35.51, 35.49, 31.43, 31.38, 30.7, 29.0, 26.3, 26.2, 26.1, 24.9 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.6; HRMS (ESI): m/z calcd for C.sub.28H.sub.43BO.sub.4Na [M.sup.++Na]: 477.3149. found: 477.3146.

EXAMPLE 16

(E)-2-(1,2-Di(thiophen-2-yl)vinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

(56) ##STR00023##

(57) The reaction was performed for 24 h at ambient temperature, after which an additional 5 mol % of the ruthenium catalyst was added and stirring was continued at 50° C. for 48 h; pale yellow oil (49 mg, 59%), .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 7.61 (1H, s), 7.37 (1H, dd, J=1.2, 5.0 Hz), 7.21-7.18 (1H, m), 7.12-7.09 (1H, m), 7.09-7.05 (1H, m), 6.93-6.89 (2H, m), 1.30 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 140.6, 139.2, 138.8, 131.5, 128.8, 127.4, 126.16, 126.15, 125.8, 83.9, 24.7 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 31.3; HRMS (ESI): m/z calcd for C.sub.16H.sub.19BO.sub.2S.sub.2Na [M.sup.++Na]: 341.0815. found: 341.0811.

EXAMPLE 17

(E)-4,4,5,5-Tetramethyl-2-(oct-2-en-2-yl)-1,3,2-dioxaborolane

(58) ##STR00024##

(59) Colorless oil (163 mg, 68%); reaction time=3 h; spectroscopic data of the major isomer .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 6.05 (1H, t, J=7.0 Hz), 2.29 (2H, q, J=6.9 Hz), 1.77-1.71 (2H, m), 1.42-1.15 (19H, m), 0.87 (3H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 147.4, 82.7, 31.4, 30.9, 29.6, 24.8, 22.5, 22.3, 14.0 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.3; HRMS (ESI): m/z calcd for C.sub.14H.sub.27BO.sub.2Na [M.sup.++Na]: 261.1999. found: 261.1996.

EXAMPLE 18

(E)-2-(4,4-Dimethylpent-2-en-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

(60) ##STR00025##

(61) Colorless oil (758 mg, 67%); reaction time=1 h; spectroscopic data of the major isomer .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 6.27 (1H, d, J=1.6 Hz), 1.79 (3H, d, J=1.6 Hz), 1.24 (12H, s), 1.13 (9H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 155.0, 83.1, 34.2, 30.3, 24.8, 14.8 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 31.1; HRMS (ESI): m/z calcd for C.sub.13H.sub.25BO.sub.2Na [M.sup.++Na]: 247.1837. found: 247.1839.

EXAMPLE 19

(E)-7-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)oct-6-en-1-yl undec-10-enoate

(62) ##STR00026##

(63) Colorless oil (49 mg, 60%); reaction time=3 h; spectroscopic data of the major isomer .sup.1H NMR (CDCl.sub.3, 300 MHz): δ 6.017 (1H, m), 5.78-5.72 (1H, m), 4.96-4.87 (2H, m), 4.02 (2H, m), 2.36-2.30 (2H, m), 2-30-2.25 (2H, m), 2.05-2.00 (2H, m), 1.72 (3H, s), 1.59-1.54 (4H, m), 1.33-1.26 (8H, m), 1.26-1.24 (6H, m), 1.25 (12H, s), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 174.0, 146.9, 139.2, 114.1, 82.8, 64.4, 30.7, 34.5, 33.8, 29.5, 29.3, 29.2, 29.1, 29.0, 28.9, 28.4, 25.3, 25.0, 24.8, 22.3 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.1; HRMS (ESI): m/z calcd for C.sub.25H.sub.45BO.sub.4Na [M.sup.++Na]: 443.3315. found: 443.3319.

EXAMPLE 20

(E)-2-(3-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)but-2-en-1-yl)isoindoline-1,3-dione

(64) Colorless oil (143 mg, 88%);

(65) ##STR00027##
reaction time=2 h; spectroscopic data of the major isomer .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 7.87-7.74 (2H, m), 7.73-7.58 (2H, m), 5.97 (1H, t, J=6.4 Hz), 4.62 (2H, d, J=6.6 Hz), 1.75 (3H, s), 1.31 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 168.0, 139.0, 133.7, 132.3, 123.0, 83.4, 38.4, 24.9, 16.9 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.6; HRMS (ESI): m/z calcd for C.sub.18H.sub.22BO.sub.4NNa [M.sup.+]: 327.1641. found: 327.1641.

EXAMPLE 21

tert-Butyl (((1R,2S,E)-1-cyclohexyl-2-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pent-3-en-1-yl)oxy)dimethylsilane

(66) ##STR00028##

(67) Colorless oil (106 mg, 70%); reaction time=2 h; spectroscopic data of the major isomer .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 6.26 (1H, q, J=1.5, 3.2 Hz), 3.26-3.22 (1H, m), 2.79-2.68 (1H, m), 1.64 (3H, d, J=1.7 Hz), 1.22-1.20 (18H, m), 0.89-0.87 (14H, m), 0.85 (9H, s); .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 150.4, 82.6, 80.4, 42.0, 36.8, 30.9, 28.6, 26.8, 26.6, 26.3, 25.0, 24.8, 22.7, 17.5, −3.3 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 30.9; HRMS (ESI): m/z calcd for C.sub.24H.sub.47BO.sub.3SiNa [M.sup.++Na]: 445.3276. found: 445.3279.

EXAMPLE 22

(E)-4,4,5,5-Tetramethyl-2-(1-(2-(methylthio)phenyl)prop-1-en-2-yl)-1,3,2-dioxaborolane

(68) ##STR00029##

(69) Colorless oil, (54 mg, 91%), reaction time=160 min, spectroscopic data of the major isomer .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 7.25 (1H, bs), 7.16-7.13 (2H, m), 7.13-7.11 (1H, m), 7.05-7.03 (1H, m), 2.35 (3H, s), 1.76 (3H, d, J=1.76 Hz), 1.23 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 143.3, 139.2, 135.4, 128.4, 126.6, 124.2, 123.1, 82.4, 23.8, 14.8, 14.6 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 77 MHz): δ 31.1, HRMS (ESI): m/z calcd for C.sub.16H.sub.23BO.sub.2SNa [M.sup.++Na]: 313.1404. found: 313.1404.

EXAMPLE 23

(E)-Methyl-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)prop-1-en-1-yl)benzoate

(70) ##STR00030##

(71) Color-less oil, (106 mg, 70%); reaction time=3 h; spectroscopic data of the major isomer .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 7.85-7.83 (2H, m), 7.30-7.26 (2H, m), 6.84 (1H, s), 3.81 (s, 3H), 1.92 (3H, d, J=1.7 Hz), 1.18 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 166.95, 143.46, 139.69, 129.13, 127.87, 83.60, 24.58, 23.53 (the C-atom directly attached to boron is broadened and could not be precisely localized); spectroscopic data of the minor isomer .sup.1HNMR (CDCl.sub.3, 400 MHz): δ 7.88-7.86 (2H, m), 7.32-7.26 (2H, m), 6.48 (1H, q, J=7.0, 14.1 Hz), 3.80 (3H, s), 1.99 (3H, d, J=1.7 Hz), 1.24 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 167.1, 148.2, 144.5, 129.4, 127.0, 83.5, 51.9, 24.7, 17.9 (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): 31.5; HRMS (ESI): m/z calcd for C.sub.17H.sub.23BO.sub.4Na [M.sup.++Na]: 325.1580. found: 325.1581.

EXAMPLE 24

(E)-4,4,5,5-Tetramethyl-2-(1-(4-(trifluoromethyl)phenyl)prop-1-en-2-yl)-1,3,2-dioxaborolane

(72) ##STR00031##

(73) Yellow oil (100 mg, 64%); reaction time=80 min, spectroscopic data of the major isomer: .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 7.57-7.50 (2H, m), 7.48-7.40 (2H, m), 6.94 (1H, s), 2.02 (3H, d, J=1.5 Hz), 1.27 (12H, s); .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 142.1, 139.1, 128.0 (2C), 124.4 (q), 83.3, 24.3, 23.2 (the C-atom directly attached to boron is broadened and could not be precisely localized); spectroscopic data of the minor isomer .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 7.56-7.50 (2H, m), 7.47-7.39 (2H, m), 6.56 (1H, q, J=7.0, 14.1 Hz), 2.11 (3H, d, J=7.0 Hz), 1.34 (12H, 5), .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 146.9, 144.8, 127.1 (2C), 124.6 (q), 83.4, 24.5, 17.6; (the C-atom directly attached to boron is broadened and could not be precisely localized); .sup.11B NMR (CDCl.sub.3, 128 MHz): δ 29.7; HRMS (ESI): m/z calcd for C.sub.16H.sub.20BO.sub.2F.sub.3Na [M.sup.+]: 312.1511. found: 312.1508.

EXAMPLE 25

(E)-11-Methyl-1,8-dioxacyclotetradec-11-ene-2,7-dione

(74) ##STR00032##

(75) Iodomethane (10.6 μL, 0.170 mmol) and KOH (24 mg, 0.426 mmol) were added to a solution of Pd(dba).sub.2 (4.08 mg, 0.007 mmol, 5 mol %), [HCy.sub.3P]BF.sub.4 (7.84 mg, 0.021 mmol, 15 mol %) and alkenyl boronate E-2 (50 mg, 0.142 mmol) in THF (1 mL) under argon. After stirring for 12 h at ambient temperature, the mixture was poured into diethyl ether (20 mL) before it was filtered through a pad of silica, which was carefully rinsed with diethyl ether (3×5 mL). Evaporation of the combined filtrates followed by flash chromatography (EtOAc/Hex, 4:1) gave the title compound as a colorless oil (18 mg, 53%). .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 5.20 (1H, t, J=7.0, 14.1 Hz), 4.20 (2H, t, J=5.4 Hz), 4.13 (2H, t, J=5.5 Hz), 2.44-2.25 (8H, m), 1.64 (3H, s), 1.63 (4H, m); .sup.13C NMR (CDCl.sub.3, 125 MHz): δ 173.3, 173.1, 132.2, 123.7, 64.0, 60.9, 38.5, 35.0, 34.9, 27.2, 24.8, 24.6, 15.2; HRMS (ESI): m/z calcd for C.sub.13H.sub.20O.sub.4Na [M.sup.++Na]: 263.1251. found: 263.1253.

EXAMPLE 26

(E)-1,8-Dioxacyclotetradec-11-ene-2,7-dione

(76) ##STR00033##

(77) AgF (21.6 mg, 0.170 mmol) was added to a solution of E-2 (30 mg, 0.08 mmol) in THF/MeOH/H.sub.2O (10:9:1) (1 mL) under argon and the resulting mixture was stirred for 3 h in the dark. Insoluble materials were filtered off and carefully washed with Et.sub.2O and EtOAc (3 mL each), the combined filtrates were evaporated and the residue was purified by flash chromatography (hexane/EtOAc, 4:1) to give the title compound as a colorless oil (15 mg, 78%; E/Z=98:2). .sup.1H NMR (CDCl.sub.3, 400 MHz): δ 5.47-5.43 (2H, m), 4.18-4.09 (4H, m), 2.44-2.24 (8H, m), 1.69-1.57 (4H, m); .sup.13O NMR (CDCl.sub.3, 125 MHz): δ 173.2, 129.2, 63.1, 35.0, 31.9, 24.7; HRMS (ESI): m/z calcd for C.sub.12H.sub.18O.sub.4Na [M.sup.++Na]: 249.1095. found: 249.1097.