TWO STEP METHOD OF PRODUCING TRIARLYAMINE COMPOUNDS HAVING TWO ALKYL ALCOHOLS IN A SINGLE REACTION VESSEL

Abstract

The present invention provides a simple, cost effective and time saving two step method for synthesizing triarylamines comprising two alkyl alcohols in a single vessel. The resulting triarylamines are synthesized without the need for the usual protection and the deprotection steps. The reaction proceeds in two steps in a single reaction vessel whereby a primary arylamine is reacted with two equivalents of a halogenated aryl alkyl alcohol in the presence of a catalytic amount of palladium precursor, ligand, solvent and base.

Claims

1. A method for forming triarylamine compounds comprising two alkyl alcohol groups in a single comprising the steps: 1. reacting two equivalents of a halogenated aryl alkyl alcohol with a primary aryl amine in the presence of a base, solvent, palladium precursor and ligand(s), and 2. adding an aqueous acid wherein the trialkylsilyl groups are cleaved in the presence of the acid to regenerate the free hydroxyl groups in the formed triarylamine compounds.

2. The method of claim 1 where in the two equivalents of halogenated aryl alkyl alcohol are represented as follows:
X—Ar((C.sub.nH.sub.2n)—OH).sub.2 wherein: X is a halogen, Ar is an aryl group; and C.sub.nH.sub.2n is an alkyl group.

3. The method of claim 2 wherein Ar is a phenyl group.

4. The method of claim 2 wherein X is selected from the group consisting of chlorine, bromine and iodine.

5. The method of claim 4 wherein X is chlorine.

6. The method of claim 4 wherein X is bromine.

7. The method of claim 2 wherein C.sub.nH.sub.2n is a lower alkyl group having between 1 and 12 carbon atoms.

8. The method of claim 2 wherein is (C.sub.nH.sub.2n)—OH is a primary alkyl alcohol.

9. The method of claim 1 wherein the base is an alkaline metal salt of a bis(trialkylsilyl)amide, represented by the general formula MN(SiR.sub.3).sub.2. wherein: M is an alkaline metal ion, N is a nitrogen atom; and R is an alkyl group.

10. The method of claim 9 wherein M is a lithium ion.

11. The method of claim 9 wherein R is a methyl group.

12. The method of claim 1 wherein the palladium precursor is selected from the group consisting of tris(dibenzylideneacetone)dipalladium (Pd.sub.2(dba).sub.3) and palladium acetate.

13. The method of claim 12 wherein the palladium precursor is tris(dibenzylideneacetone)dipalladium (Pd.sub.2(dba).sub.3).

14. The method of claim 1 wherein the ligand is selected from the group consisting of 2-Di-tert-butylphosphino-2′,4′,6′-triisopropylbiphenyl (tBuXPhos), 1,1′-Ferrocenediyl-bis(diphenylphosphine) (DPPF), tri-tert-butylphosphine, tri-tert-butylphosphonium tetrafluoroborate, 2-Dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (RuPhos) and 2-(Dicyclohexylphosphino)3,6-dimethoxy-2′,4′,6′-triisopropyl-1,1′-biphenyl (BrettPhos).

15. The method of claim 14 wherein the ligand is 2-Di-tert-butylphosphino-2′,4′,6′-triisopropylbiphenyl (tBuXPhos).

16. The method of claim 14 wherein the ligand is tri-tert-butylphosphonium tetrafluoroborate

17. The method of claim 14 wherein the ligand is a mixture of 2-Dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (RuPhos) and 2-(Dicyclohexylphosphino)3,6-dimethoxy-2′,4′,6′-triisopropyl-1,1′-biphenyl (BrettPhos).

18. The method of claim 1 wherein the solvent is selected from the group consisting of: cyclic ethers such as tetrahydrofuran (THF), ethers such as diethyl ether or tert-butyl methyl ether, aromatic solvents such as toluene or xylene, acetate solvents such as ethyl acetate or butyl acetate, aliphatic solvents such as hexane or decane, and amide solvents such as dimethyl formamide (DMF), dimethyl acetamide (DMAc) and N-methylpyrrolidone (NMP).

19. The method of claim 18 wherein the solvent is tetrahydrofuran THF.

20. The method of claim 17 wherein the ratio of 2-Dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (RuPhos) to 2-(Dicyclohexylphosphino)3,6-dimethoxy-2′,4′,6′-triisopropyl-1,1′-biphenyl (BrettPhos) is about 1:4.

21. The method of claim 1 wherein the aqueous acid is selected from the group consisting of hydrochloric acid, hydrobromic acid and sulfuric acid.

Description

DETAILED DESCRIPTION

[0016] This disclosure is not limited to particular embodiments described herein, and some components and processes may be varied by one of skill, based on this disclosure. The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0017] In this specification and the claims that follow, singular forms such as “a,” “an,” and “the” include plural forms unless the content clearly dictates otherwise. In addition, reference may be made to a number of terms that shall be defined as follows:

[0018] An amination is the process of reacting an N—H bond with an organic molecule to form a N—C bond. The carbon may be an alkyl carbon or an aryl carbon. The Buchwald-Hartwig amination is the process of reacting an N—H group with an aryl halide to form a N-aryl bond wherein the nitrogen is bonded directly to a carbon of an aryl group. The terms “Buchwald-Hartwig amination” and “Buchwald-Hartwig reaction” may be used interchangeably.

[0019] The term “aryl” refers, for example to a monocyclic aromatic species of about 6 to about 20 carbon atoms or more, such as phenyl, naphthyl, anthrycyl, and the like. Optionally, these groups may be substituted with one or more independently selected substituents, including alkyl, alkenyl, alkoxy, and nitro groups. “Ar” is shorthand for the aryl group.

[0020] The terms “hydrocarbon” and “alkane” refer, for example, to branched and unbranched molecules having the general formula C.sub.nH.sub.2n+2, wherein n is, for example, a number from 1 to about 100 or more, such as methane, ethane, n-propane, isopropane, n-butane, isobutane, tert-butane, octane, decane, tetradecane, hexadecane, eicosane, tetracosane, and the like. Alkanes may be substituted by replacing hydrogen atoms with one or more functional groups. The term “aliphatic” refers, for example, to straight-chain molecules, and may be used to describe acyclic, unbranched alkanes. The term “long-chain” refers, for example, to hydrocarbon chains in which n is a number of from about 8 to about 60, such as from about 20 to about 45 or from about 30 to about 40. The term “short-chain” refers, for example, to hydrocarbon chains in which n is an integer of from about 1 to about 7, such as from about 2 to about 5 or from about 3 to about 4.

[0021] The term “alkyl” refers, for example, to a branched or unbranched saturated hydrocarbon group having one substituent and derived from an alkane and having the general formula C.sub.nH.sub.2n+1, wherein n is, for example, a number from 1 to about 100 or more, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, octyl, decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like. An example of an alkyl group having the general formula C.sub.nH.sub.2n+1 is (C.sub.2H.sub.5)—OH. An alkyl group having two substituents has the general formula C.sub.nH.sub.2n, An example of which Ar(C.sub.2H.sub.4)—OH. The term “lower alkyl” refers, for example, to an alkyl group of from about 1 to about 12 carbon atoms. “Halogenated alkyl” refers, for example, to an alkyl group in which at least one hydrogen atom, and optionally all hydrogen atoms, is replaced by a halogen atom.

[0022] The term “arylamine” refers, for example, to moieties containing both aryl and amine groups. Exemplary arylamine groups have the structure Ar—NRR′, in which Ar represents an aryl group and R and R′ are groups that may be independently selected from hydrogen and substituted and unsubstituted alkyl, alkenyl, aryl, and other suitable functional groups. The term “primary arylamine” may be used interchangeably with “aniline,” since both refer to compounds possessing the general structure H.sub.2N—Ar. The term “triarylamine” refers, for example, to arylamine compounds having the general structure NArAr′Ar″, in which Ar, Ar′ and Ar″ represent independently selected aryl groups.

[0023] The term “organic molecule” refers, for example, to any molecule that is made up predominantly of carbon and hydrogen, such as, for example, alkanes and arylamines. The term “heteroatom” refers, for example, to any atom other than carbon and hydrogen. Typical heteroatoms included in organic molecules include oxygen, nitrogen, sulfur and the like.

[0024] The term “alcohol” refers, for example, to an alkyl group in which one or more of the hydrogen atoms has been replaced by an “OH” group. The terms “alcohol” and “hydroxy” may be used interchangeably. The term “lower alcohol” refers, for example, to an alkyl group of about 1 to about 6 carbon atoms in which at least one, and optionally all, of the hydrogen atoms has been replaced by an —OH group.

[0025] The term “primary alcohol” refers to an alcohol attached to a carbon that is bonded to only one other carbon atom. This type of alcohol is also called a terminal alcohol since it is bonded to the last carbon in an alkyl chain. The term “secondary alcohol” refers to an alcohol that is attached to a carbon that is bonded to two other carbon atoms.

[0026] The term “halogenated aryl alkyl alcohol” refers to compounds having the general structure X—Ar(C.sub.nH.sub.2n)—OH, where X represents a halogen atom and C.sub.nH.sub.2n refers to an alkyl group.

[0027] “Amine” refers, for example, to an alkyl moiety in which one or more of the hydrogen atoms has been replaced by an —NH.sub.2 group. The term “lower amine” refers, for example, to an alkyl group of about 1 to about 6 carbon atoms in which at least one, and optionally all, of the hydrogen atoms has been replaced by an —NH.sub.2 group.

[0028] The term “derivative” refers, for example, to compounds that are derived from another compound and maintain the same general structure as the compound from which they are derived. For example, saturated alcohols and saturated amines are derivatives of alkanes.

[0029] The term “analogous” refers, for example, to any number of series of organic compounds that have similar chemical properties and that differ by a constant relative molecular mass. For example, Cl—Ar and Br—Ar are analogous compounds because they are both halogen-substituted aryl compounds.

[0030] The term “ion” refers to atoms that bear a charge by virtue of an excess (negative charge) or deficiency (positive charge) of electrons required to give a charge of 0 and is based on the atomic number of the element.

[0031] The term “saturated” refers, for example, to compounds containing only single bonds. The term “unsaturated” refers, for example, to compounds that contain one or more double bonds and/or one or more triple bonds.

[0032] The term “reflux” refers, for example, to the process of boiling a liquid, condensing the vapor and returning the vapor to the original container. When a liquid is refluxed, the temperature of the boiling liquid remains constant. The term “boiling point” refers, for example, to the temperature at which the saturated vapor pressure of a liquid is equal to the external atmospheric pressure.

[0033] The terms “one or more” and “at least one” herein mean that the description includes instances in which one of the subsequently described circumstances occurs, and that the description includes instances in which more than one of the subsequently described circumstances occurs.

[0034] An improved method for producing triarylamines directly from a primary arylamine and a halogenated aryl alkyl alcohol is provided herein. The reaction proceeds in two steps in a single reaction vessel whereby a primary arylamine is reacted with two equivalents of a halogenated aryl alkyl alcohol in the presence of a catalytic amount of palladium precursor, ligand, solvent and base. Performing the reaction in two steps in a single reaction vessel as opposed to three steps and three reaction vessels saves time and money. Fewer reaction steps and reaction vessels also leads to higher yields. Additionally, a one vessel or pot reaction is much more convenient than the three vessels required in standard procedures.

[0035] The result is surprising since the preparation of triarylamines comprising one or more alcohol groups using previous methods included the costly and time consuming alcohol protection and deprotection steps. Without wishing to be bound by theory, one possibility for the alcohol protection requirement is that deprotonation of the alcohol in the presence of base gives a reactive alkoxide that can react with the palladium catalyst. Protection of the alcohol with a functional group that is impervious to the basic conditions of the reaction prevents this reaction pathway. Upon completion of the Buchwald-Hartwig amination, the protecting group may be removed to regenerate the alcohol functionality. Following the method of the present invention eliminates this costly and time consuming alcohol protection/deprotection process. Therefore, this process is very practical and applicable to the industrial scale preparation of triarylamines comprising one or more alkyl alcohol functional groups. This shorter, improved process is now described in detail.

[0036] Equations 1-3 below show a three-step process for preparing a triarylamine comprising two alkyl alcohol functional groups. Note that “P” represents a generalized protecting group, and “Pd” represents a palladium precursor and a ligand.

##STR00001##

[0037] Equation 4 below shows the inventive two-step method of the present invention for preparing the same triphenylamine.

##STR00002##

[0038] The base suitable for use in the present invention comprises an alkaline metal salt of a bis(trialkylsilyl)amide, represented by the general formula MN(SiR.sub.3).sub.2, here M is an alkaline metal, N is a nitrogen atom and R is an alkyl group. In one embodiment, M is any alkaline metal ion. In another embodiment, M is selected from the list metal ions including lithium, sodium, and potassium. In another embodiment, M is lithium. In one embodiment, R is a lower alkyl group containing between 1 and about 12 carbon atoms. In another embodiment, R is a methyl group. Bis(trialkylsilyl)amide bases, such as lithium bis(trimethylsilyl)amide, may be purchased or prepared and used as a solid or a solution in an organic solvent.

[0039] The primary arylamine can be any suitable primary arylamine having the general formula H.sub.2N—Ar.sup.1. Ar.sup.1 independently represents any known substituted or unsubstituted aromatic component or a substituted or unsubstituted aryl group having from 2 to about 15 conjugate bonded or fused benzene rings and could include, but is not limited to, phenyl, naphthyl, anthryl, phenanthryl, and the like. The substituents on Ar.sup.1 can be suitably selected to represent hydrogen, a halogen, an alkyl group having from 1 to about 20 carbon atoms, a hydrocarbon radical having from 1 to about 20 carbon atoms, an aryl group optionally substituted by one or more alkyl groups, an alkyl group containing a heteroatom such as oxygen, nitrogen, sulfur, and the like, having from 1 to about 20 carbon atoms, a hydrocarbon radical containing a heteroatom such as oxygen, nitrogen, sulfur, and the like, having from 1 to about 20 carbon atoms, an aryl group containing a heteroatom such as oxygen, nitrogen, sulfur, and the like, optionally substituted by one or more alkyl groups, and the like.

[0040] The aryl alkyl alcohol can be any suitable aryl alkyl alcohol having the general formula X—Ar.sup.2((C.sub.nH.sub.2n)—OH).sub.2. X represents any suitable halide that is reactive in the Buchwald-Hartwig amination. In one embodiment, the halide is selected from the list including chloride, bromide and iodide. In another embodiment, the halide is selected from chlorine and bromine. In another embodiment the halide is chlorine. Ar.sup.2 represents any known substituted or unsubstituted aromatic component or a substituted or unsubstituted aryl group having from 2 to about 15 conjugate bonded or fused benzene rings and could include, but is not limited to, phenyl, naphthyl, anthryl, phenanthryl, and the like. The substituents on Ar.sup.2 can be suitably selected to represent hydrogen, a halogen, an alkyl group having from 1 to about 20 carbon atoms, a hydrocarbon radical having from 1 to about 20 carbon atoms, an aryl group optionally substituted by one or more alkyl groups, an alkyl group containing a heteroatom such as oxygen, nitrogen, sulfur, and the like, having from 1 to about 20 carbon atoms, a hydrocarbon radical containing a heteroatom such as oxygen, nitrogen, sulfur, and the like, having from 1 to about 20 carbon atoms, an aryl group containing a heteroatom such as oxygen, nitrogen, sulfur, and the like, optionally substituted by one or more alkyl groups, and the like. One of the substituents bonded to Ar.sup.2 is an alkyl alcohol represented by the general formula (C.sub.nH.sub.2n)—OH. In principle, the alkyl group, C.sub.nH.sub.2n, is any branched or unbranched saturated hydrocarbon wherein n is, for example, a number between 1 and 100. In one embodiment, the alkyl group is a lower alkyl with a value of n between 1 and 12. In another embodiment, the value of n is between 1 and 6. In yet another embodiment, the value of n is between 2 and 4. In principle, the alkyl alcohol group may reside in the ortho, meta, or para position relative to the halide. However, the inventors have found that only substitution at the para position provides the electrical properties necessary for use in an organic photoreceptor.

[0041] The alcohol of the alkyl alcohol may be a primary alcohol, a secondary alcohol, or a mixture thereof. In one embodiment, both of the alcohol groups of the of the alkyl alcohol are primary alcohols. In a second embodiment, both of the alcohol groups of the of the alkyl alcohol are secondary alcohols.

[0042] The palladium precursor is any source of palladium source capable of catalyzing the Buchwald-Hartwig reaction in the presence of the appropriate ligand. The palladium precursor should have an oxidation state of 0, ‘Pd(0)’, or be capable of being reduced to Pd(0) under the reaction conditions. In the event that the palladium precursor is not Pd(0), but rather for example, ‘Pd(II)’, addition of a small amounts reducing agent such as a tertiary amine or boronic acid may be required to generate Pd(0). Pd(II) refers to the +2 oxidation state of palladium. Pd(II) will not lead to a functional catalyst for the present invention. Addition of small amounts of reducing agent(s) such as triethylamine or phenyl boronic acid which are required to reduce Pd(II) to Pd(0) are regarded as falling within the scope of the present invention. Examples of Pd(0) sources include, but are not limited to tris(dibenzylideneacetone)dipalladium (Pd.sub.2(dba).sub.3), and di(dibenzylideneacetone)palladium (Pd(dba).sub.2). Sources of Pd(II) include, but are not limited to palladium chloride, palladium bromide, palladium iodide, palladium acetate, palladium acetylacetonate, palladium hexafluoroacetylacetonate, palladium trifluoroacetate, allyl palladium chloride dimer, (2,2′-bipyridine)dichloropalladium, bis(benzonitrile)dichloropalladium, bis(acetonitrile)dichloropalladium, (bicyclo[2.2.1]hepta-2,5-diene)dichloropalladium, dichloro(1,5-cyclooctadiene)palladium, dibromobis(triphenylphosphine)palladium, dichloro(N,N,N′,N′-tetramethylethylenediamine)palladium, dichloro(1,10-phenathroline)palladium, dichlorobis(triphenylphosphinepalladium), ammonium tetrachloropalladate, diaminedibromopalladium, diaminedichloropalladium, diaminediiodopalladium, potassium tetrabromopalladate, potassium tetrachloropalladate and sodium tetrachloropalladate. In one aspect, the palladium precursor is chosen from tris(dibenzylideneacetone)dipalladium, and palladium acetate. In another embodiment, the palladium precursor is tris(dibenzylideneacetone)dipalladium.

[0043] The ligand is any molecule capable of reacting with the palladium precursor and facilitating the Buchwald-Hartwig reaction. These ligands include, but are not limited to dialkylbiarylphosphines, ferrocenyl diphenyl and dialkyl phosphines and bulky, electron rich phosphines. Examples of dialkylbiarylphosphine ligands include: 2-Dicyclohexylphosphino-2′-(N,N-dimethylamino)biphenyl (DavePhos), 2-Dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (Xphos), 2-Dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (Sphos), 2-Di-tert-butylphosphino-2′,4′,6′-triisopropylbiphenyl (tBuXPhos), (2-Biphenyl)dicyclohexylphosphine, 2-(Dicyclohexylphosphino)biphenyl (CyJohnPhos), (2-Biphenyl)di-tert-butylphosphine (JohnPhos), 2-Dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (RuPhos), 2-Di-tert-butylphosphino-2′-methylbiphenyl (tBuMePhos), 2-Di-tert-butylphosphino-3,4,5,6-tetramethyl-2′,4′,6′-triisopropyl-1,1′-biphenyl 2-Di-tert-butylphosphino-2′-methylbiphenyl (tBuMePhos), 2-Di-tert-butylphosphino-3,4,5,6-tetramethyl-2′,4′,6′-triisopropyl-1,1′-biphenyl (Tetramethyl tBuXPhos), and 2-(Dicyclohexylphosphino)3,6-dimethoxy-2′,4′,6′-triisopropyl-1,1′-biphenyl (BrettPhos). Examples ferrocenyl diphenyl and dialkyl phosphines include: 1,1′-Ferrocenediyl-bis(diphenylphosphine) (DPPF), 1,2,3,4,5-Pentaphenyl-1′-(di-tert-butylphosphino)ferrocene (Q-Phos), 1,1′-Bis(di-tert-butylphosphino)ferrocene, 1,1′-Bis(dicyclohexylphosphino)ferrocene and 1,1′-Bis(diisopropylphosphino)ferrocene. An example ligand is a mixture of 2-Dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (RuPhos) and 2-(Dicyclohexylphosphino)3,6-dimethoxy-2′,4′,6′-triisopropyl-1,1′-biphenyl (BrettPhos). A preferred ratio of 2-Dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (RuPhos) to 2-(Dicyclohexylphosphino)3,6-dimethoxy-2′,4′,6′-triisopropyl-1,1′-biphenyl (BrettPhos) is about 1:4. An example of a bulky, electron rich phosphines is tri tert-butylphosphine. Bulky, electron rich ligands such as tri tert-butylphosphine are extremely air sensitive. Manipulation of air sensitive materials must be done under inert atomosphere, such as provided by a glove box. Use of air stable materials is therefore preferred. A useful air stable variant of the tri-tert-butylphosphine ligand is tri-tert-butylphosphonium tetrafluoroborate.

##STR00003##

The phosphonium ion is deprotonated under the basic conditions of the Buchwald-Hartwig reaction, thus liberating the active tri tert-butylphosphine ligand. In one embodiment, the ligand is tri-tert-butylphosphonium tetrafluoroborate.

[0044] The inventors have discovered that aromatic solvents such as toluene are preferred solvents. The Buchwald-Hartwig reaction is accompanied by formation of a solid. In non-aromatic solvents, such as tetrahydrofuran (THF), this solid coats the inside of the reaction vessel. In order for reactions to reach completion, the reactants must be stirred in a homogeneous manner. A build-up of solids may therefore inhibit complete reaction. When an aromatic solvent, such as toluene, is used, the solid stirs as small particles that do not build-up on the walls of the flask. The slurry is therefore effectively stirred, allowing for complete reaction to occur. Furthermore, aromatic solvents such as toluene typically have higher boiling points than non-aromatic solvents such as THF. Many catalytic processes, such as the Buchwald-Hartwig reaction, occur faster as the reaction temperature increases. Faster reactions save time and money. The aromatic solvent should be also be non-halogenated. Halogenated aromatic solvents may enter into the Buchwald-Hartwig reaction, thus lowering the yield of the desired product. Additionally, the aromatic solvent should be free of moisture. Water molecules react with the bis(trimethylsilyl)amide base and thus should be excluded from the solvent. The aromatic solvent may be any solvent that contains an aromatic ring structure. Examples of aromatic solvents include benzene, toluene and xylene. In an embodiment, the solvent is toluene. The solvent may comprise a mixture of solvents, so long as at least about 30% (wt./wt.) of the solvent mixture is an aromatic solvent. In an embodiment, the solvent is comprised of a 2/1 mixture of THF and toluene.

[0045] The alkyl hydroxy group is regenerated by reaction with an aqueous acid. Without wishing to be bound by theory, the bis(trialkysilyl) base may undergo a displacement reaction with the alkyl hydroxy groups to generate the compound shown below.

##STR00004##

[0046] In other words, an in situ hydroxy protection occurs during the Buchwald-Hartwig reaction. The trialkylsilyl groups are cleaved in the presence of acid to regenerate the free hydroxy groups of the final product. The aqueous acid may be any aqueous acid that cleaves the proposed trialkylsilyl groups and regenerates the free hydroxy groups. In one embodiment, the aqueous acid is an inorganic acid selected from the group including aqueous hydrochloric acid (HCl), aqueous hydrobromic acid (HBr) and aqueous sulfuric acid. A preferred aqueous acid is aqueous HCl.

EXAMPLES

Example 1

[0047] An oven dried 1 L round bottom flask equipped with a reflux condenser, magnetic stir bar and gas inlet/outlet valves was charged with 3-(4-bromophenyl)propan-1-ol (17.2 g, 80 mmoles) and aniline (3.72 g, 40 mmoles). A solution of 1M lithium bis trimethylsilylamide in toluene (200 mL, 200 mmoles) was then added via cannula transfer. The resulting dark brown slurry was stirred under nitrogen for 30 minutes. Under a strong stream of nitrogen, Pd.sub.2(dba).sub.3 (183 mg, 0.2 mmoles), and tri-tert-butylphosphonium tetrafluoroborate (174 mg, 0.6 mmoles) were added at once. The stopcock was immediately replaced and the flask was heated to 100° C. under nitrogen. After about 30 minutes, solid particles began appearing in the rapidly stirring mixture. The reaction was allowed to proceed overnight. The next morning, evenly distributed brown particles were observed. These particles had not collected on the walls of the flask. The reaction was allowed to proceed for a total time of 17 h. The flask was cooled and 200 mL of toluene was added to the flask. Aqueous HCl (2M, 200 mL) was added dropwise to the vigorously stirring mixture. During the addition, the solid slowly dissolved. The resulting two-phase mixture was neutralized using a saturated solution of NaHCO.sub.3. The organic layer was separated and washed with 2×200 mL of water, and 3×3 300 mL of brine. The resulting dark brown solution was filtered through a short bed of Celite® and dried over MgSO.sub.4. The mixture was filtered to remove the MgSO.sub.4 and solvent was removed under vacuum to give the triphenylamine comprising two propyl alcohol groups as a dark brown viscous liquid.

Example 2

[0048] An oven dried 1 L round bottom flask equipped with a reflux condenser, magnetic stir bar and gas inlet/outlet valves was charged with 3-(4-bromophenyl)propan-1-ol (17.2 g, 80 moles) and aniline (3.72 mg, 40 mmoles). A solution of 1M lithium bis trimethylsilylamide in THF (200 mL, 200 mmoles) and anhydrous toluene (100 mL) were added via cannula transfer. The resulting dark brown slurry was stirred under nitrogen for 30 minutes. Under a strong stream of nitrogen, Pd.sub.2(dba).sub.3 (183 mg, 0.20 mmoles), and tri-tert-butylphosphonium tetrafluoroborate (174 mg, 0.60 mmoles) were added at once. The stopcock was immediately replaced and the flask was heated to reflux under nitrogen. After about 30 minutes, solid particles appeared in the rapidly stirring mixture. The reaction was allowed to proceed overnight. The next morning, a solid was observed both on the walls of the flask and stirring in the solvent mixture. The reaction was allowed to proceed for a total time of 20 h. The flask was cooled and 300 mL of toluene was added to the flask. Aqueous HCl (2M, 200 mL) was added dropwise to the vigorously stirring mixture. During the addition, the solid slowly dissolved. The resulting two-phase mixture was neutralized using a saturated solution of NaHCO.sub.3. The organic layer was separated and washed with 2×200 mL of water, and 3×3 300 mL of brine. The resulting dark brown solution was filtered through a short bed of Celite® and dried over MgSO.sub.4. The mixture was filtered to remove the MgSO.sub.4 and solvent was removed under vacuum to give the triphenylamine comprising two propyl alcohol groups as a dark brown viscous liquid.