Chlorophosphines, reactions with

A combination of a substitution reaction with a chlorophosphine followed by a hydroboration and boron-zinc exchange allows the preparation of the mixed 1,2-diphosphine 207 in good yield (Scheme 62). ... 

It should be noted that the reactions described above cannot be performed in the reverse order, i.e., preparation of the chlorophosphine followed by reaction with LiAsPhz. The reaction of lithium diphenylphosphine with cfr-l,2-dichloroethylene, even with a large excess of the latter, yields only cw-l,2-bisdiphenylphosphinoethylene and not the chlorophosphine, and while 2-chloroethyldiphenylphosphine can be prepared, its isolation is more difficult, and yields are lower than for the corresponding arsine. ... 

Direct Synthesis. Some chlorophosphines and arsines react directly with metallic nickel in the same way as carbon monoxide to form the tet-rasubstituted derivatives. This reaction was described initially for PCUMe and PCUPh by Quinn (156)] soon afterwards Maier (125) obtained analogous reactions with AsBr2Me and PBr2Me. 

The outcome of the reaction between 1,8-dilithionaphthalene and di-chlorophosphines RPCI2 is dependent on the nature of the R group at phosphorus. Thus, the reaction with phenyldichlorophosphine leads to the diphosphine... 

Several reports have appeared of the application of unusual organometallic reagents in phosphine synthesis. Treatment of 2-lithiopyridine with anhydrous zinc chloride results in the formation of a 2-pyridylzinc reagent which can be used to introduce the 2-pyridyl group at phosphorus in a controlled manner. Thus, e.g., in its reaction with phenyldichlorophosphine, the 2-pyridyl-(phenyl)chlorophosphine (15) is formed. This has then been converted via the phosphide route into a new class of binucleating ligands (16). The sterically crowded dichlorophosphine (17) (accessible from the reaction of phosphorus trichloride with lithium diphenyl(2-pyridyl)methanide) is converted into the thermally stable phosphirane (18) on treatment with calcium, strontium or barium cyclooctatetraenide.The reaction of phenyldichlorophosphine with the readily accessible titanacycle (19) affords a convenient route to the phosphetene (20). ... 

Chiralphosphines. These important ligands can be obtained from chiral organoboranes by consecutive reaction with EtjZn and various chlorophosphines. 

A number of non-routine reactions of halogenophosphines are worthy of note. The first aliphatic phosphenium cation featuring a phosphorus-sulfur bond (17) has been obtained by treatment of the chlorophosphine (18) with aluminium trichloride in dichloromethane solution. A new synthesis of acyclic chiral t-phosphines has been developed which employs selective, sequential alkylation of the chloro(amino) phosphines (19) by Grignard and organolithium reagents. The key intermediates (19) are readily prepared by the... 

Schmidpeter and co-workers continue to report their thorough studies into the reactions of ylidyl phosphines and chlorophosphines with trimethylsilyl-phosphines. Some of their more significant results are summarised in Scheme 2. Generally, treatment of ylidyl chlorophosphines (19) with trimethylsilyl-phosphines proceeds with the elimination of chlorotrimethylsilane to yield ylidyl diphosphines (20) and (21). The reaction of (19) with lithium diphos-... 

An overview of the preparations of some more recent examples of ditertiary phosphines is given below. One popular route still continues to be generation of a reactive organolithium or magnesium reagent and reaction with a suitable chlorophosphine. This procedure can be used to prepare (84) (Scheme 6), containing either an arene88 or naphthalene (85) (Equation (25)) backbone. 87... 

Reactions with Alkenes,—Further examples have been reported of the cycloaddition of 1,3-dienes to chlorophosphines. - Certain of these reactions show a high overall stereoselectivity when hydrogen sulphide is used to quench the initial complex. Thus the sulphide (11) is formed as one isomer only. 15-Phospha-steroids and 17-phospha-steroids have been prepared by this type of reaction. In general, both possible isomers (at phosphorus) are formed, as with the oxides (12). ... 

The 1,3-oxaphosphinines are represented by the dihydro derivatives (301), which are formed from 3-hydroxypropylphosphine (299) by reaction with iV-arylpivalimidoyl chlorides (300). The P=C bond in (301) is highly reactive it adds HCl to give the chlorophosphine (302), and is reduced by methylphenylphosphine forming 2-/-butyl-1,3-oxaphosphinane (303) (Scheme 60) <91CB493>. 

Coupling reactions. Electrochemical coupling reactions with (bpy)NiBr2 catalysis include those between alkenyl bromides and a-halo esters, aryl and pyridyl halides, as well as aryl and chlorophosphines. ... 

The preparation of aminophosphines from chlorophosphines and an amine is usually straightforward. Two equivalents of the amine or the addition of one equivalent of a tertiary amine per chloro group is necessary to neutralize the acid formed, unless a trimethylsi-lylamine is used good yields of aminochlorophosphines are obtained from dichlorophos-phines and 2 mol of an amine or 1 mol of a trimethylsilylamine. Representative examples are the preparation of aminophosphines from dichloro(phenyl)phosphine (equations 36 and 37 ) and the preparation of some functionalized aminophosphines (equations 38 and 39 ). Examples of reactions with trimethylsilylamines are given in equations 40 and 41. Hydrazinophosphines are known and may be prepared from chlorophosphines, e.g. 2,2-dimethylhydrazinodiphenylphosphine (equation 42). ... 

Various alkylene-bis(aminophosphines) (42) and (43) have been synthesized and (42 = 4) characterized by its reactions with chalcogenides, BH3, BBrs, PCI3, MeOH, HgS, and 83. The bis-aminophosphines (44) and (45) have been prepared by standard methods and used for the preparation of the corresponding chlorophosphines (46). Other new synthons of related type are (47). Thus (47 X = NMe) has been used to prepare a series of 1-methyl-1,3-benzazaphos-pholes (48), and (48 R = H) could be lithiated at carbon with interesting possibilities for further substitution. The X-ray structures of (49) and (50), two products from the reaction of tris(diethylamino)phosphine with aniline, have been reported. ... 

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