Versatile process for the preparation of acylphosphines

Abstract

A versatile, highly efficient process for the preparation of acylphosphines such as mono- and bisacylphosphines via reaction of phosphines (PH.sub.3 and higher homologues) or silylated phosphines with acylhalides in the presence of at least one lewis acid. Further a novel acyl phosphines obtainable by the process.

Claims

1. Compounds of formula (Ia)
[LAF][P(COR.sup.2).sub.2].sub.q(Ia) wherein: LAF represents a q-valent Lewis Acid Fragment (LAF) that is a cationic structural unit obtainable by removing q anionic substituents from a Lewis acid, q is an integer of 1 to 5, and R.sup.2 is aryl or heterocyclyl alkyl or alkenyl whereby the aforementioned alkyl and alkenyl substituent R.sup.2 is either not, once, twice or more than twice interrupted by non-successive functional groups selected from the group consisting of: O, NR.sup.4, CO, OCO, O(CO)O, NR.sup.4(CO), NR.sup.4(CO)O, O(CO)NR.sup.4, NR.sup.4(CO)NR.sup.4, and either not, additionally or alternatively either once, twice or more than twice interrupted by bivalent residues selected from the group consisting of heterocyclo-diyl, and aryldiyl, and either not, additionally or alternatively either once, twice or more than twice substituted by substituents selected from the group consisting of: oxo, halogen, cyano, C.sub.6-C.sub.14-aryl; heterocyclyl, C.sub.1-C.sub.8-alkoxy, C.sub.1-C.sub.8-alkylthio, SO.sub.2N(R.sup.4).sub.2, NR.sup.4SO.sub.2R.sup.5, N(R.sup.4).sub.2, CO.sub.2N(R.sup.4).sub.2, COR.sup.4, OCOR.sup.5, O(CO)OR.sup.5, NR.sup.4(CO)R.sup.4, NR.sup.4(CO)OR.sup.4, O(CO)N(R.sup.4).sub.2, NR.sup.4(CO)N(R.sup.4).sub.2, whereby in all formulae where used R.sup.4 is independently selected from the group consisting of hydrogen, C.sub.1-C.sub.8-alkyl, C.sub.6-C.sub.14-aryl, and heterocyclyl, or N(R.sup.4).sub.2 as a whole is a N-containing heterocycle, and R.sup.5 is independently selected from the group consisting of C.sub.1-C.sub.8-alkyl, C.sub.6-C.sub.14-aryl, and heterocyclyl, or N(R.sup.5).sub.2 as a whole is a N-containing heterocycle, with the exception of diphenylboryldipivaloylphosphide and 1-oxa-3-oxonia-5.sup.3-phospha-2-borata-4,6-dimethylcyclohexadiene and 1-oxa-3-oxonia-5.sup.3-phospha-2-borata-4,6-diphenylcyclohexadiene: ##STR00003## with R=methyl or phenyl.

2. Compounds according to claim 1, wherein R.sup.2 is C.sub.6-C.sub.14-aryl or C.sub.4-C.sub.13-heteroaryl.

3. Compounds according to claim 1, wherein LAF is dichloroaluminyl (AlCl.sub.2) or difluoroboryl (BF.sub.2) with q being 1 chloroaluminyl (AlCl) or fluoroboryl (BF) with q being 2 or aluminum (Al) or boron (B) with q being 3.

4. The following compounds of formula (Ia) according to claim 1: dichloroaluminyl-bismesitoylphosphide, difluoroboryl-bismesitoylphosphide, dichloroaluminyl-bisbenzoylphosphide, difluoroboryl-bisbenzoylphosphide, chloroaluminyl-bis(bismesitoylphosphide), chloroaluminyl-bis(bisbenzoylphosphide), chloroboryl-bis(bismesitoylphosphide), chloroboryl-bis(bisbenzoyl-phosphide), aluminium-tris(bismesitoylphosphide), aluminium-tris(bisnaphthoylphosphide) and/or aluminium-tris(bisbenzoylphosphide).

5. Compounds according to claim 1, wherein LAF is obtainable from a Lewis acid selected from the group consisting of methyl aluminoxane (MAO) and compounds represented by formula (IV)
MR.sup.L.sub.(r)X.sub.(z-r)(IV) wherein z is 2, 3, 4 or 5 r is 0 or an integer of at maximum z M if z is 2 is an element selected from the group consisting of Sn, Zn, Fe, and Mn if z is 3 is an element selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Fe, B, Al, Ga, In, and As if z is 4 is an element selected from the group consisting of V, Ti, Zr, Hf, and Sn if z is 5 is an element selected from the group consisting of V, P, As, Sb, and Bi X is independently selected from the group consisting of fluoride, chloride, bromide, iodide, azide, isocyanate, thiocyanate, isothiocyanate, and cyanide R.sup.L represents C.sub.1-C.sub.18-alkyl, C.sub.1-C.sub.18-haloalkyl, C.sub.1-C.sub.18-alkoxy, C.sub.1-C.sub.18-haloalkoxy, C.sub.6-C.sub.14-aryl, C.sub.7-C.sub.18-arylalkyl, C.sub.6-C.sub.14-aryloxy, C.sub.7-C.sub.18-arylalkoxy, O(HCO), O(CO)(C.sub.1-C.sub.18-alkyl), O(CO)(C.sub.6-C.sub.14-aryl) or O(CO)(C.sub.7-C.sub.18-arylalkyl) or two R.sup.L together represent C.sub.4-C.sub.18-alkandiyl, C.sub.4-C.sub.18-haloalkandiyl, C.sub.4-C.sub.18-alkanedioxy, C.sub.4-C.sub.18-haloalkanedioxy, C.sub.6-C.sub.14-aryldiyl, C.sub.7-C.sub.18-arylalkanediyl, C.sub.4-C.sub.18-alkanedioxy, C.sub.4-C.sub.18-haloalkanedioxy, C.sub.6-C.sub.14-aryl)-(CO)O, (C.sub.1-C.sub.18-alkyl)-(CO)O, O(CO)(C.sub.6-C.sub.14-aryl)-(CO)O, O(CO)(C.sub.7-C.sub.18-arylalkyl)-(CO)O, or oxo (O).

6. Compounds according to claim 5, wherein LAF is a structural unit of formula (IVa)
MR.sup.L.sub.(rr)X.sub.(zz-rr)(IVa) wherein M, X and R.sup.L have the same meaning as described for formula (IV) zz is (z-q) with q being an integer of 1 up to z, wherein z has the same meaning as described for formula (IV) and rr is 0 or an integer of at maximum zz.

7. A process for the preparation of compounds of formula (I):
[LAF].sub.s[P.sub.x(R.sup.H).sub.m(R.sup.1).sub.n(COR.sup.2).sub.p].sub.q(I) wherein s is either 0 or, provided that x is 1, m and n are 0 and p is 2, s is 1 q if s is 0, is 1 and if s is 1, is an integer of 1 to 5 x is an integer of 1 to 15 or 20 m, n and p are selected such that: m is zero or an integer of 1 or more n is zero or an integer of 1 or more P is an integer of 1 or more and one of the following conditions is met: TABLE-US-00003 If x is an integer of 1 to 9 (m+n+p) is (x+2) where s is 0 (m+n+p) is (x+1) where s is 1 x is an integer of 3 to 10 (m+n+p) is x x is an integer of 4 to 12 (m+n+p) is (x2) x is an integer of 5 to 10 or 13 (m+n+p) is (x4) x is an integer of 7 to 14 (n+m+p) is (x6) x is 10, 11 or 15 (m+n+p) is (x8) x = is 12 or 20 (m+n+p) is (x10) LAF represents a q-valent Lewis Acid Fragment (LAF) that is a cationic structural unit obtainable by removing q anionic substituents from a Lewis acid, R.sup.H are independently of each other either hydrogen, or a residue of formula Si(R.sup.3).sub.3, wherein the substituents R.sup.3 are independently of each other selected from the group consisting of C.sub.1-C.sub.18-alkyl and C.sub.6-C.sub.14-aryl R.sup.1 and R.sup.2 are independently of each other aryl or heterocyclyl, alkyl or alkenyl whereby the aforementioned alkyl and alkenyl substituents R.sup.1 and/or R.sup.2 are either not, once, twice or more than twice interrupted by non-successive functional groups selected from the group consisting of: O, NR.sup.4, CO, OCO, O(CO)O, NR.sup.4(CO), NR.sup.4(CO)O, O(CO)NR.sup.4, NR.sup.4(CO)NR.sup.4, and either not, additionally or alternatively either once, twice or more than twice interrupted by bivalent residues selected from the group consisting of heterocyclo-diyl, and aryldiyl, and either not, additionally or alternatively either once, twice or more than twice substituted by substituents selected from the group consisting of: oxo, halogen, cyano, C.sub.6-C.sub.14-aryl; heterocyclyl, C.sub.1-C.sub.8-alkoxy, C.sub.1-C.sub.8-alkylthio, SO.sub.2N(R.sup.4).sub.2, NR.sup.4SO.sub.2R.sup.5, N(R.sup.4).sub.2, CO.sub.2N(R.sup.4).sub.2, COR.sup.4, OCOR.sup.5, O(CO)OR.sup.5, NR.sup.4(CO)R.sup.4, NR.sup.4(CO)OR.sup.4, O(CO)N(R.sup.4).sub.2, NR.sup.4(CO)N(R.sup.4).sub.2, whereby in all formulae where used R.sup.4 is independently selected from the group consisting of hydrogen, C.sub.1-C.sub.8-alkyl, C.sub.6-C.sub.14-aryl, and heterocyclyl or N(R.sup.4).sub.2 as a whole is a N-containing heterocycle, R.sup.5 is independently selected from the group consisting of C.sub.1-C.sub.8-alkyl, C.sub.6-C.sub.14-aryl, and heterocyclyl or N(R.sup.5).sub.2 as a whole is a N-containing heterocycle the process comprising at least the step of reacting compounds of formula (II)
P.sub.x(R.sup.H).sub.(m+p)(R.sup.1).sub.n(II) wherein R.sup.H, R.sup.1, x, and n and the sum of (m+n+p) is as defined above for the sum of (m+n+p) for compounds of formula (I) with s being 0 where x=1 and the sum of (m+p) is an integer of 1 or more that fits the equation given for the sum of (m+n+p) for compounds of formula (I) with s being 0 where x is 1 with compounds of formula (III),
R.sup.2COHal(III) wherein R.sup.2 is as defined above for compounds of formula (I) and Hal represents fluoro, chloro, bromo or iodo whereby the reaction is carried out in the presence of at least one Lewis acid.

8. The process according to claim 7, wherein in compounds of formulae (I) and (III) R.sup.2 is C.sub.6-C.sub.14-aryl or C.sub.4-C.sub.13-heteroaryl.

9. The process according to claim 7, wherein as compounds of formula (II) phosphine (PH3), tris(trimethylsilyl)phosphine (P(SiMe)3) or tris(trimethylsilyl)-heptaphosphine ((P7(SiMe)3) are employed.

10. The process according to claim 7, wherein as compounds of formula (I) benzoylphosphine, mesitoylphosphine, bismesitoylphosphine, dibenzoylphosphine dichloroaluminyl-bismesitoylphosphide, difluoroboryl-bismesitoylphosphide, dichloroaluminyl-bisbenzoylphosphide, difluoroboryl-bisbenzoylphosphide, chloroaluminyl-bis(bismesitoylphosphide), chloroaluminyl-bis(bisbenzoyl-phosphide), chloroboryl-bis(bismesitoylphosphide), chloroboryl-bis(bisbenzoyl-phosphide), aluminium-tris(bismesitoylphosphide), aluminium-tris(bisnaphthoylphosphide) and/or aluminium-tris(bisbenzoylphosphide) are prepared.

11. The process according to claim 7, wherein the at least one Lewis acid is selected from the group including methyl aluminoxane (MAO) and compounds represented by formula (IV)
MR.sup.L.sub.(r)X.sub.(z-r)(IV) wherein z is 2, 3, 4 or 5 r is 0 or an integer of at maximum z M if z is 2 is an element selected from the group consisting of Sn, Zn, Fe and Mn if z is 3 is an element selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Fe, B, Al, Ga, In, As if z is 4 is an element selected from the group consisting of V, Ti, Zr, Hf, Sn if z is 5 is an element selected from the group consisting of V, P, As, Sb, Bi X is independently selected from the group consisting of fluoride, chloride, bromide, iodide, azide, isocyanate, thiocyanate, isothiocyanate or cyanide R.sup.L represents C.sub.1-C.sub.18-alkyl, C.sub.1-C.sub.18-halo alkyl, C.sub.1-C.sub.18-alkoxy, C.sub.1-C.sub.18-haloalkoxy, C.sub.1-C.sub.14-aryl, C.sub.7-C.sub.18 arylalkyl, C.sub.6-C.sub.14-aryloxy, C.sub.7-C.sub.18-arylalkoxy, O(HCO), O(CO)(C.sub.1-C.sub.18-alkyl), O(CO)(C.sub.6-C.sub.14-aryl) and O(CO)(C.sub.7-C.sub.18-arylalkyl) or two R.sup.L together represent C.sub.4-C.sub.18-alkandiyl, C.sub.4-C.sub.18-haloalkandiyl, C.sub.4-C.sub.18-alkanedioxy, C.sub.4-C.sub.18-haloalkanedioxy, C.sub.6-C.sub.14-aryldiyl, C.sub.7-C.sub.18-arylalkanediyl, C.sub.6-C.sub.14-aryldioxy, C.sub.7-C.sub.18-arylalkanedioxy, O(CO)(C.sub.1-C.sub.18-alkyl)-(CO)O, O(CO)(C.sub.6-C.sub.14-aryl)-(CO)O and O(CO)(C.sub.7-C.sub.18-arylalkyl)-(CO)O, or oxo (O).

12. The process according to claim 11, wherein the Lewis Acid Fragments (LAF) are structural units of formula (IVa)
MR.sup.L.sub.(rr)X.sub.(zz-rr)(IVa) wherein M, X and R.sup.L shall have the same meaning as described for formula (IV) zz is (z-q) with q being an integer of 1 up to z, wherein z shall have the same meaning as described for formula (IV) and rr is 0 or an integer of at maximum zz.

13. The process according to claim 7, wherein the Lewis Acids are aluminum trichloride and/or boron trifluoride.

14. A process for preparing compounds of formula (Ib)
HP(COR.sup.2).sub.2(Ib) by reacting compounds of formula (Ia) according to claim 1 with a proton source.

15. A process according to claim 14 wherein proton sources include water, acids and alcohols or a mixture thereof.

16. A method comprising reacting compounds of claim 1 as precursor materials for substituted bisacylphosphine oxides.

Description

EXAMPLES

I Materials and Methods

(1) All reactions were carried out under argon using either standard Schlenk techniques or an argon-filled glove box. Solvents were purified using an Innovative Technology PureSolv MD 7 solvent purification system. All reagents were used as received from commercial suppliers unless otherwise stated. The compounds Na.sub.3P.sub.7 and (Me.sub.3Si).sub.3P.sub.7 were synthesized following literature procedures, e.g. M. Cica-Hudi, J. Bender, S. H. Schlindwein, M. Bispinghoff, M. Nieger, H. Grtzmacher, D. Gudat, Eur. J. Inorg. Chem. 2015, 5, 649. X-ray single crystal diffraction studies were performed on an Oxford XCalibur S diffractometer equipped with a molybdenum X-ray tube (=0.7107 ).

II General Methods for the Preparation of Acylphosphines

Example 1a Acylation of PH.SUB.3 .with Mesitoyl Chloride in the Presence of BF.SUB.3..Et.SUB.2.O

(2) A 100 mL two neck round bottom flask containing mesitoylchloride (MesCOCl) (4 mL, 24 mmol, 1 eq.) and boron trifluoride etherate (BF.sub.3.Et.sub.2O) (0.15 mL, 1.2 mmol, 0.05 eq.) in dichloromethane (DCM) (20 mL) was connected via one neck to the PH.sub.3 supply and via the other neck to a bleach scrubber. The flask was flushed with PH.sub.3, then the stopcock to the bleach scrubber was closed and the system pressurized with 50 kPa PH.sub.3. Typically, the PH.sub.3 consumption was finished after 3 to 6 hours. The flask was stirred for another 12 h at 20 C. Then the system was opened to the bleach scrubber and flushed with argon for 30 min to remove all traces of PH.sub.3. The crude reaction mixture was analyzed by .sup.31P-NMR spectroscopy. Based on the integrals of the NMR signals, the mixture was found to contain 70% bis(mesitoylphosphine) HP(COMes).sub.2 [(.sup.31P)=89.2 (s, enol), 2.2 (d, .sup.1J.sub.PH=246.8 Hz, keto) ppm], 16% difluoroborylbis(mesitoylphosphide) [BF.sub.2]P(COMes).sub.2 [(.sup.31P)=93.4 (s) ppm] and 14% mono(mesitoylphosphine) H.sub.2P(COMes) [(.sup.31P)=97.4 (t, .sup.1J.sub.PH=218.3 Hz) ppm]. MesCOCl (0.33 mL, 2.0 mmol) and BF.sub.3.Et.sub.2O (0.013 mL, 0.10 mmol) were again added and the mixture stirred for another 60 min. Subsequently, the mixture was analyzed by .sup.31P-NMR spectroscopy and found to contain 76% HP(COMes).sub.2 and 16% [BF.sub.2]P(COMes).sub.2. Degassed water (25 mL) was added and the suspension stirred for 24 h at 20 C. The aqueous phase was extracted with DCM (35 mL). The solvent was removed under reduced pressure from the combined organic phases, yielding HP(COMes).sub.2 as a bright yellow crystalline solid. The analytical data corresponded to published data.

Example 1b Acylation of PH.SUB.3 .with Mesitoyl Chloride in the Presence of BF.SUB.3..Et.SUB.2.O

(3) A steel autoclave fitted with a 100 mL ceramic cell containing mesitoylchloride (MesCOCl) (4 mL, 24 mmol, 1 eq.) and boron trifluoride etherate (BF.sub.3.Et.sub.2O) (0.15 mL, 1.2 mmol, 0.05 eq.) in dichloromethane (DCM) (20 mL) was connected via an inlet to the PH.sub.3 supply and via an outlet to to a bleach scrubber. The autoclave was flushed with PH.sub.3 and then the valve to the bleach scrubber was closed and the system pressurized with 250 kPa PH.sub.3. Typically, the PH.sub.3 consumption was finished after 3 to 6 hours. The flask was stirred for another 12 h at 20 C. Then the system was opened to the bleach scrubber and flushed with argon for 30 min to remove all traces of PH.sub.3. The crude reaction mixture was analyzed by .sup.31P-NMR spectroscopy. Based on the integrals of the NMR signals, the mixture was found to be substantially identical to the one obtained in example 1a).

Example 2 Acylation of (Me.SUB.3.Si).SUB.3.P.SUB.7 .with Mesitoyl Chloride in the Presence of BF.SUB.3..Et.SUB.2.O

(4) To a solution of MesCOCl (2.48 mL, 15 mmol, 6 eq.) and BF.sub.3.Et.sub.2O (0.95 mL, 7.5 mmol, 3 eq.) in DCM (10 mL) was added solid tris(trimethylsilyl) heptaphosphide (Me.sub.3Si).sub.3P.sub.7 (1.09 g, 2.5 mmol, 1 eq.). The orange solution was stirred for 16 h and the solvent removed under reduced pressure to obtain (MesCO).sub.3P.sub.7 as a bright yellow solid (1.63 g, 2.48 mmol, 99%). An analytically pure sample could be obtained by layering a saturated THF solution with hexane, collecting the yellow crystalline on a glass frit and drying it under reduced pressure.

(5) Mp 198-199 C. (from THF). Analysis Found: C, 55.7; H, 5.5; N, 0.2. Calc. for C.sub.30H.sub.33O.sub.3P.sub.7: C, 54.7; H, 5.1; N, 0.0. .sup.1H-NMR (300 MHz, CD.sub.2Cl.sub.2): =6.85 (s, 6H, Ar), 2.30 (s, 9H, CH.sub.3), 2.24 (s, 18H, CH.sub.3) ppm. .sup.31P-NMR (CDCl.sub.3, 121 MHz): =135.0 to 122.0 (m, 3P), 140.0 to 151.0 (m, 1P), 148.5 to 159.5 (m, 3P) ppm.

Example 3 Acylation of PH.SUB.3 .with Mesitoyl Chloride in the Presence of AlCl.SUB.3 .Yielding Aluminum tris[bis(mesitoyl)phosphide][Al(.SUP.Mes.BAP).SUB.3.]

(6) A 100 mL round bottom flask with two Normag spindle valves was charged with MesCOCl (6 eq., 90 mmol, 15.0 mL), AlCl.sub.3 (1 eq., 15 mmol, 2.00 g) and tetrachloroethene C.sub.2Cl.sub.4 (35 mL). One side of the flask was connected to a PH.sub.3 gas bottle and the other side to a series of three bleach bathes. The system was purged with argon for 15 min to remove traces of oxygen. Then it was pressurized with 80 kPa PH.sub.3 under vigorous stirring. An incipient pressure drop was followed by a pressure rise to about 120 kPa due to the formation of HCl as by-product. The system was opened to the bleach bath and pressurized with PH.sub.3 again. This procedure was repeated several times until the pressure remained stable. The orange suspension was stirred for another 16 h under 80 kPa PH.sub.3 pressure, before it was opened to the bleach bath and purged with argon for 60 min. The suspension was transferred to a 100 mL round bottom Schlenk flask and the solvent removed to a minimum under reduced pressure. Precipitation of the product was completed by addition of n-hexane (50 mL). The product was collected on a G3 glass frit, washed with n-hexane (310 mL) and dried under reduced pressure, yielding the aluminum complex [Al(.sup.MesBAP).sub.3] as a bright orange powder (14.0 g, 14.0 mmol, 93%).

(7) Mp 137-139 C. .sup.1H-NMR (300 MHz, CDCl.sub.3): =6.73 (s, 12H, Ar), 2.24 (s, 18H, CH.sub.3), 2.15 (s, 36H, CH.sub.3) ppm. .sup.13C{.sup.1H}-NMR (75 MHz, CDCl.sub.3): =229.0 (d, .sup.1J.sub.PC=88.2 Hz, C(O)P), 140.0 (d, .sup.2J.sub.PC=27.9 Hz, C.sub.ipso, 138.4 (s, C.sub.para), 134.0 (d, C.sub.ortho), 128.3 (s, C.sub.meta), 21.2 (s, CH.sub.3), 19.6 (s, CH.sub.3) ppm. .sup.31P-NMR (CDCl.sub.3, 121 MHz): =99.0 (s) ppm.

Example 4 Acylation of PH.SUB.3 .with Benzoyl Chloride in the Presence of AlCl.SUB.3 .Yielding Aluminum tris[bis(benzoyl)phosphide] [Al(.SUP.Ph.BAP).SUB.3]

(8) A 100 mL round bottom flask with two Normag spindle valves was charged with benzoylchloride (PhCOCl, 6 eq., 17.4 mmol, 2.00 mL), AlCl.sub.3 (1 eq., 2.90 mmol, 290 mg) and tetrachloroethene C.sub.2Cl.sub.4 (10 mL). Reaction and work-up were carried out as described above, yielding the aluminum complex [Al(.sup.PhBAP).sub.3] as a bright red powder (1.35 g, 1.80 mmol, 62%).

(9) .sup.31P-NMR (CDCl.sub.3, 121 MHz): =68.7 (s) ppm.

Example 5 Synthesis of bis(mesitoyl)phosphine HP(COMes).SUB.2 .from [Al(.SUP.Mes.BAP).SUB.3.]

(10) A suspension of the aluminum complex [Al(.sup.MesBAP).sub.3] prepared according to example 3 (1 eq, 0.100 mmol, 100 mg) and citric acid (2 eq., 0.200 mmol, 38 mg) in toluene (2.0 mL) was refluxed for 6 hours. The resulting yellow suspension was filtered over a G3 glass frit and the solvent of the filtrate removed under reduced pressure, yielding bis(mesitoyl)phosphine HP(COMes).sub.2 as a bright yellow powder (90 mg, 0.275 mmol, 92%).

(11) .sup.1H-NMR (300 MHz, C.sub.6D.sub.6): =19.3 (d, .sup.3J.sub.PH=2.0 Hz, OHO), 6.63 (s, Ar), 6.63 (s, Ar), 5.44 (d, .sup.1J.sub.PH=244.2 Hz, PH), 2.34 (s, CH.sub.3), 2.18 (s, CH.sub.3), 2.03 (s, CH.sub.3), 2.00 (s, CH.sub.3) ppm. .sup.31P-NMR (CDCl.sub.3, 121 MHz): =90.2 (s, enol), 3.8 (d, .sup.1J.sub.PH=243.6 Hz, keto) ppm.

Example 6 Synthesis of bis(benzoyl)phosphine HP(COPh).SUB.2 .from [Al(.SUP.Ph.BAP).SUB.3.]

(12) A suspension of the aluminum complex [Al(.sup.PhBAP).sub.3] (1 eq, 0.100 mmol, 75 mg) prepared according to example 4 and citric acid (2 eq., 0.200 mmol, 38 mg) in toluene (2.0 mL) was refluxed for 2.5 hours. The resulting orange suspension was filtered over a G3 glass frit and the solvent of the filtrate removed under reduced pressure, yielding bis(benzoyl)phosphine HP(COPh).sub.2 as a bright orange powder (70 mg, 0.289 mmol, 96%).

(13) .sup.1H-NMR (300 MHz, C.sub.6D.sub.6): =20.1 (d, .sup.3J.sub.PH=3.1 Hz, OHO), 8.20-8.10 (s, 4H, Ar), 7.12-6.95 (s, 6H, Ar) ppm. .sup.13C{.sup.1H}-NMR (75 MHz, C.sub.6D.sub.6): =228.3 (d, .sup.1J.sub.PC=86.1 Hz, C(O)P), 140.1 (d, .sup.2J.sub.PC=26.7 Hz, C.sub.ipso), 144.0 (d, .sup.5J.sub.PC=2.8 Hz, C.sub.para), 128.9 (s, C.sub.meta), 126.5 (d, .sup.3J.sub.PC=16.7 Hz, C.sub.ortho) ppm. .sup.31P-NMR (CDCl.sub.3, 121 MHz): =90.2 (s, enol), 3.8 (d, .sup.1J.sub.PH=243.6 Hz, keto) ppm.

Example 7a Synthesis of difluoroboryl-bismesitoylphosphide [BF.SUB.2.(.SUP.Mes.BAP)] from PH.SUB.3

(14) A 100 mL two neck round-bottom flask containing mesitoylchloride (MesCOCl) (5.0 mL, 30 mmol, 1 eq.) and boron trifluoride diethyl etherate (BF.sub.3.Et.sub.2O, 2.38 mL, 18.8 mmol, 1 eq.) in C.sub.2Cl.sub.4 (20 mL) was exposed to 800 hPa PH.sub.3 for 48 h. After purging the system, the orange suspension was transferred to a Schlenk flask with, the solvent evaporated to a minimum and precipitation of the product completed by addition of n-hexane (40 mL). The product was collected on a glass frit, washed with n-hexane (35 mL) and dried under reduced pressure, yielding the boron complex difluoroboryl-bismesitoylphosphide [BF.sub.2(.sup.MesBAP)] as a yellow solid (3.90 g, 10.4 mmol, 69%). Single crystals were obtained from toluene at 30 C.

(15) .sup.1H-NMR (300 MHz, CDCl.sub.3): =6.93 (s, 3H, Mes-H), 2.37 (s, 12H, CH.sub.3), 2.32 (s, 6H, CH.sub.3) ppm. .sup.13C{.sup.1H}-NMR (300 MHz, CDCl.sub.3): =237.7 (dt, .sup.1J.sub.PC=95.0, .sup.3J.sub.BC=2.2 Hz, C(O)P), 141.6 (d, J=1.4 Hz, p-Mes), 135.4 (d, .sup.3J.sub.PC=3.7 Hz, o-Mes), 135.3 (d, .sup.2J.sub.PC=21.2 Hz, ipso-Mes), 129.4 (s, m-Mes), 21.3 (s, p-CH.sub.3), 20.1 (d, .sup.4J.sub.PC=3.8 Hz, o-CH.sub.3) ppm. .sup.31P-NMR (121 MHz, CDCl.sub.3): =94.3 (s) ppm.

Example 7b Synthesis of bis(mesitoyl)phosphine HP(COMes).SUB.2 .from difluoroboryl-bismesitoylphosphide [BF.SUB.2.(.SUP.Mes.BAP)]

(16) A solution of the boron complex [BF.sub.2(.sup.MesBAP)] (1.33 g, 3.55 mmol) in THF (15 mL) and water (2 mL) was stirred for 15 min at 20 C. Volatiles were removed from the bright yellow solution under reduced pressure, yielding the phosphine .sup.MesBAP-H as a bright yellow powder (1.16 g, 3.55 mmol, 100%).

Example 8 Acylation of PH.SUB.3 .with neat mesitoyl chloride in the presence of AlCl.SUB.3 .Yielding Aluminum tris [bis(mesitoyl)phosphide] [Al(.SUP.Mes.BAP).SUB.3.]

(17) A 100 mL round-bottom flask with two Normag spindle valves was charged with mesitoylchloride (10.0 mL, 60.0 mmol, 4 eq.) and AlCl.sub.3 (333 mg, 2.50 mmol, 1 eq.). The reaction and the workup were carried out as described in example 3, yielding the aluminum complex [Al(.sup.MesBAP).sub.3] as a bright orange powder (2.38 g, 2.37 mmol, 95%, corresponding to AlCl.sub.3)

(18) .sup.1H-NMR (300 MHz, CDCl.sub.3): =6.75 (s, 12H, Mes-H), 2.25 (s, 18H, CH.sub.3), 2.17 (s, 36H, CH.sub.3) ppm.

(19) .sup.13C{.sup.1H}-NMR (75 MHz, CDCl.sub.3): =240.3 (d, .sup.1J.sub.PC=92.2 Hz, C(O)P), 140.0 (d, .sup.2J.sub.PC=28.0 Hz, ipso-Mes, 138.4 (d, .sup.5J.sub.PC=1.3 Hz, p-Mes), 134.0 (d, .sup.3J.sub.PC=3.0 Hz, o-Mes), 128.3 (s, m-Mes), 21.2 (s, p-CH.sub.3), 19.6 (d, .sup.4J.sub.PC=2.7 Hz, o-CH.sub.3) ppm.

(20) .sup.31P-NMR (121 MHz, CDCl.sub.3): =99.0 (s) ppm.

(21) Analysis Found C, 71.0; H, 6.7; N, 0.1. Calc. for C.sub.60H.sub.66O.sub.6P.sub.3Al: C, 71.8; H, 6.6; N, 0. Mp>180 C. (decomposition, from toluene).

Example 9 Acylation of PH.SUB.3 .with 1-naphthoyl Chloride in the Presence of AlCl.SUB.3 .Yielding Aluminum tris [bis(naphthoyl)phosphide] [Al(.SUP.Naph.BAP).SUB.3.]

(22) A thick walled 100 mL round bottomed flask with two Normag taps was charged with anhydrous AlCl.sub.3 (333 mg, 2.5 mmol) in a glovebox. To this 1-naphthoyl chloride (2.26 mL, 15 mmol) and C.sub.2Cl.sub.4 (10 mL) were added. The mixture was placed under 1 bar Ar to check for leaks. The mixture was then stirred for 30 minutes, and a pale yellow solution formed. The Ar pressure was released and the flask repressurised with 800 hPa PH.sub.3, an orange colour was immediately observed. After 1 hour the atmosphere was replaced with fresh PH.sub.3 to remove any HCl formed. The mixture was vigorously stirred over the weekend (3 nights) and turned bright orange, with the formation of a bright orange precipitate. A .sup.31P NMR spectrum showed the solution to be complete. The reaction mixture was then transferred into a Schlenk flask with THF (40 mL). The solution was concentrated to approximately 10 mL and then hexane (20 mL) added to complete the precipitation. This was then filtered under Ar and the solid washed with a hexane (20 mL). The solid was dried on the frit under vacuum and collected to yield Al(.sup.NaphBAP).sub.3 as a bright orange solid (1.947 g, 74%).

Example 10 Acylation of PH.SUB.3 .with Mesitoyl Chloride in the Presence of ZnCl.SUB.2

(23) A thick walled 100 mL round bottomed flask with two Normag taps was charged with anhydrous ZnCl.sub.2 (340.7 mg, 2.5 mmol) in a glovebox. To this mesitoyl chloride (1.66 mL, 10 mmol) and C.sub.2Cl.sub.4 (10 mL) were added. The mixture was placed under 1 bar Ar and then stirred for 15 minutes, and a pale yellow colour observed with partial dissolving of the ZnCl.sub.2. The Ar pressure was released and the flask repressurised with 800 hPa PH.sub.3. After 1 hour the atmosphere was replaced with fresh PH.sub.3 to remove any HCl formed. The mixture was vigorously stirred overnight and turned a darker yellow, and some yellow precipitate was observed on the flask walls. A .sup.31P NMR spectrum showed the solution to contain both HP(COMes).sub.2 and H.sub.2P(COMes) in a ratio of approximately 1:1. The reaction mixture was again pressurised with PH.sub.3 and left over the weekend (3 nights), the .sup.31P NMR now showed approximately 90% HP(COMes).sub.2. The reaction mixture was then transferred into a Schlenk flask with THF (20 mL). The solution was concentrated to approximately 10 mL and then hexane (10 mL) added to complete the precipitation. This was then filtered under Ar and the filtrate then dried under vacuum to yield a sticky yellow solid (1.55 g). This was then washed with dry hexane (5 mL) to yield a yellow powder, the supernatant was removed by cannula filtration and the powder dried to yield HP(COMes).sub.2 (0.872 g, 2.67 mmol, 53%).

Example 11 Acylation of PH.SUB.3 .with Naphthoyl Chloride (NaphCOCl) in the Presence of ZnCl.SUB.2

(24) A thick walled 100 mL round bottomed flask with two Normag taps was charged with anhydrous ZnCl.sub.2 (340.7 mg, 2.5 mmol) in a glovebox. To this 1-naphthoyl chloride (1.5 mL, 10 mmol) and C.sub.2Cl.sub.4 (10 mL) were added. The mixture was placed under 1 bar Ar and then stirred for 30 minutes, and a pale yellow colour was observed with partial dissolving of the ZnCl.sub.2. The Ar pressure was released and the flask repressurised with 800 hPa PH.sub.3, and an orange colour was immediately observed. After 1 hour the atmosphere was replaced with fresh PH.sub.3 to remove any HCl formed. The mixture was vigorously stirred over the weekend (3 nights) and turned bright orange, with a bright orange precipitate observed. A .sup.31P NMR spectrum showed the solution to contain both HP(CONaph).sub.2 and H.sub.2P(CONaph) in a ratio of approximately 1:1. The reaction mixture was then left to stir under Ar for a further 2 days and no H.sub.2P(CONaph) was visible in the .sup.31P NMR spectrum. The reaction mixture was then transferred into a Schlenk flask with Toluene (20 mL) and THF (5 mL). The solution was concentrated to approximately 10 mL and then hexane (10 mL) added to complete the precipitation. This was then filtered under Ar and the filtrate then dried under vacuum to yield a sticky orange product. This was then dissolved in dry hexane (40 mL) and filtered, the hexane was removed under vacuum to yield a bright orange oil.

Example 12 Acylation of PH.SUB.3 .with Naphthoyl Chloride (NaphCOCl) in the Presence of TiCl.SUB.4

(25) TiCl.sub.4 (1 M in Tol, 2.5 mL, 2.5 mmol) was diluted with dry toluene (7.5 mL) in a thick walled 100 mL round bottomed flask with two Normag taps under Ar. To this 1-naphthoyl chloride (1.5 mL, 10 mmol) was added, the colour changed from a pale orange to a dark red. The mixture was placed under 1 bar Ar and then stirred for 15 minutes. The Ar pressure was released and the flask repressurised with 800 hPa PH.sub.3. The atmosphere was exchanged with fresh PH.sub.3 twice more; once after 1 hour and a second time after 2 hours. The reaction was stirred overnight, 16 hours. The colour changed from red to green/black in this time. When degassed water was added to the green/black solution, it turned orange and the formation of HP(CONaph).sub.2 was observed in .sup.31P NMR. When dry hexane was added to the solution, a bronze/red precipitate was obtained.

Example 13 Acylation of PH.SUB.3 .with Mesitoyl Chloride in the Presence of FeCl.SUB.3

(26) A thick walled 100 mL round bottomed flask with two Normag taps was charged with anhydrous FeCl.sub.3 (406 mg, 2.5 mmol) in a glovebox. To this mesitoyl chloride (2.45 mL, 15 mmol) and C.sub.2Cl.sub.4 (10 mL) were added. The mixture was placed under 1 bar Ar and then stirred for 15 minutes, and a pale yellow solution was observed above a sticky brown solid. The Ar pressure was released and the flask repressurised with 800 hPa PH.sub.3. After 1 hour the atmosphere was replaced with fresh PH.sub.3 to remove any HCl formed, this was repeated once more. The mixture was vigorously stirred over a weekend. A .sup.31P NMR spectrum showed a multitude of peaks, including (ppm) 90.4 and 95.7 (t, .sup.1J.sub.PH=212 Hz) which are assignable to HP(COMes).sub.2 and H.sub.2P(COMes) respectively.

Example 14 Acylation of PH.SUB.3 .with Mesitoyl Chloride in the Presence of MnCl.SUB.2

(27) A thick walled 100 mL round bottomed flask with two Normag taps was charged with anhydrous MnCl.sub.2 (315 mg, 2.5 mmol) in a glovebox. To this mesitoyl chloride (1.66 mL, 10 mmol) and toluene (10 mL) were added. The mixture was placed under 1 bar Ar and then stirred for 15 minutes, and a pale yellow solution was observed above a pinkish solid. The Ar pressure was released and the flask repressurised with 800 hPa PH.sub.3. After 1 hour the atmosphere was replaced with fresh PH.sub.3 to remove any HCl formed, this was repeated once more. The mixture was vigorously stirred for 20 hours. A .sup.31P NMR spectrum showed the presence of HP(COMes).sub.2 and H.sub.2P(COMes). The MnCl.sub.2 was filtered off and the solvent of the filtrate was removed under vacuum to yield a sticky yellow solid. The solid was washed by adding hexane (1 mL) and stirring overnight. The yellow solid was then collected by filtration and dried under vacuum to yield HP(COMes).sub.2 (0.98 g, 3 mmol, 60%).

Example 15 Acylation of PH.SUB.3 .with Mesitoyl Chloride in the Presence of FeCl.SUB.2

(28) Example 15 was carried out as example 14 with the only difference being that FeCl.sub.2 (318 mg, 2.5 mmol) was used instead of MnCl.sub.2. HP(COMes).sub.2 was obtained in a yield of 58%.

Example 16 Acylation of PH.SUB.3 .with Mesitoyl Chloride in the Presence of Methylaluminoxane (MAO)

(29) To a solution of mesitoyl chloride (4.0 mL, 24 mmol) in dichloromethane (15 mL) was added a solution of methyl aluminumoxane in toluene (1.0 mL, 0.895 g mL.sup.1, 7 wt-% Al, 2.4 mmol Al, 0.1 eq.). The resulting dark orange solution was exposed to 800 hPa PH.sub.3 for 48 h. The .sup.31P-NMR spectrum showed a broad signal at =100 ppm, which can be assigned to a mixture of different Al-complexes of HP(COMes).sub.2. After addition of H.sub.2O.sub.2 (8.0 mL, 30 wt-%, 72 mmol, 3.0 eq.) at 0 C., a sharp signal at =2 ppm was observed in the .sup.31P-spectrum, which can be assigned to (HO)OP(COMes).sub.2.