Reactions with Halophosphines

The reaction of equimolar amounts of N-vinyl-4,5,6,7-tetrahydroindole with PCI3 can be stopped at the stage of the formation of phosphine 43. The latter undergoes 

SCHEME 2.209 Phosphorylation of 2-terf-hutyl-N-vinylpyrrole with the mixture of 

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Reactions of halophosphines with conjugated heterodienes leading toP,0-, P,N-, and P,N,0-heterocycles 99UK167. 

Complexation of the latter at phosphorus with borane, followed by methanolysis of the siloxyether function, gives the related o-hydroxyaryl diazaphospholidines. The cage-like triaminophosphine (109) has been obtained from the reaction of tri(2-pyrrolyl)methane with phosphorus trichloride, in the presence of triethylamine. This compound is stable to methanolysis, hydrolysis, and aerial oxidation at room temperature. Phosphorylation of various 1,2,4-triazoles with halophosphines has given a route to the heterocyclic system (110), and routes to various [2,4,l]benzodiazaphosphinines, e.g., (Ill), have also been developed. ... 

Aminophosphines are mostly prepared by one of two routes the reaction of halophosphines (normally chlorophosphines) with amines or silylated amines (equation 32), or the... 

The hydrogen atoms of the two CH groups are acidic, in contrast to those of the BH groups, which are hydridic. Therefore, selective functionalization of the carbon atoms is possible by electrophilic substitution or deprotonation with strong bases followed by subsequent reaction with electrophiles. However, the steric bulk of the clusters requires appropriate reactivity of the electrophile to obtain the desired product in acceptable yields. Phosphorus-containing compounds such as halophosphines are suitable for this type of functionalization of carboranes. In 1963, the first reaction with phosphines was described and until today it has ranained the method of choice for phosphorus functionalization of carboranes. 

The reaction of a diphosphine with a dihalo compound, resulting in the formation of a di- or tetra-phosphonium salt2c, is a special case because if fits well with a cyclization on phosphorus, but also at the same time with a cyclization between two chains already linked to the second phosphorus (reaction 102). Another kind of ring closure on the phosphorus results from the biphilic character of halophosphines toward dienic392 or acetylenic28,393 systems (reaction 105). 

Organophosphorus compounds find wide use in the chemical industry as catalysts, intermediates, complexes, and end-use products. Arylphosphines and phosphine oxides are often produced by the reaction of a preformed Grignard reagent with a halophosphine or phosphine oxide. Yields are reduced by the production of unwanted side-reaction products such as biaryls. These unwanted products are reduced when the reaction is conducted under Barbier conditions. When alkyl and aryl halides are reacted with magnesium metal, a trihalophosphine or phosphine oxide, a metal halide or amine catalyst, in THE benzene mixtures, at reflux, good yields of phosphines or phosphine oxides are obtained [74]. For example, triphenylphosphine can be prepared in a 97.2% yield from the reaction of bromobenzene, trichlorophosphine, magnesium metal, aluminum chloride, and sodium chloride in THF-benzene at 70 80 C. 

The first characterization of simple halophosphines as the primary products of the direct reaction of white or red phosphorus with trifluoromethyl iodide at 200-220 °C under pressure was reported in 1953 by Bennett, Emeleus and Haszeldine ... 

Halophosphines are produced by reactions of phosphorus with alkyl chlorides, alkyl bromides, or aryl bromides in solution (12) and by reaction of red phosphorus in tlie presence of copper with alkyl halides in tlie vapor phase (13). Both methods require temperatures in excess of 2 )0°. The preparation of halopliosphines in solution is illustrated by the results of uncatalyzed white phosphorus reactions summarized in Table I (12). Alkyl dihalopliosphiues are the predominant products under these conditions, but appreciable yields of dialkylmonohalophos-phines are also obtained. The reaction temperature requirement de-... 

The phenyl derivatives PhPClj, PhjPCl and PCI3 itself are commercially available and a useful review of halophosphines has been published. The reaction of PCI3 with Grignard or organo-... 

Fluorophosphoranes and halophosphines usually break Si-N linkages and replace them with P-N, without forming either Si-P or Si-N-P linkages (7.135,7.179,7.256,7.458,7.488,7.489). In the absence of these reagents, however, the grouping P = N-Si is relatively stable (7.490) and (7.529). Some reactions of silyl iminophosphoranes are given in Chapter 7.10. 

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