Halides phosphinyl

A newer synthetic approach that overcomes some of the limitations inherent in the earlier methods described above has been developed by Mislow and co-workers (lOa-c). When unsymmetrically substituted phosphinyl halides are esterified with (-)-menthol, the resulting diastereomeric phosphinates can be separated by fractional crystallization (Fig. 10).4 Displacement of the menthyl-... 

Epoxide Aziridine Phosphoryl/phosphonyl/ phosphinyl halide Azo... 

Specialty-chemical level production (kilograms) of phosphines is achieved by hydride reductions of halophosphines, phosphonyl halides and esters and phosphinyl halides and esters, e.g. ... 

Coupling of Phosphoryl or Phosphinyl Amides with Phosphoryl or Phosphinyl Halides 325... 

The coupling of phosphoryl or phosphinyl amides with phosphoryl or phosphinyl halides is an excellent method for the preparation of unsymmetrical ligands, and affords the synthesis of compounds with both organic groups and chalcogens differing. 

Studies of Equilibria, Shift Reagents, and Solvent Effects.—Several studies of halogen-exchange equilibria have been reported, e.g. the exchange between phosphoryl, phosphonyl, and phosphinyl halides, P and P halides (27)... 

With the correspondingly more reactive methylphosphonic dichloride a mixture was obtained which contained traces of phosphinic acids. More important was the observation that methylphosphonic difluoride condensed smoothly with alkyl Grignard reagents to provide unsynametrical phosphinyl halides which precipitated as insoluble complexes of magnesium salts. Decomposition of the complexes with base gave the corresponding phosphinic acids, the yields of which increased as R increased... 

An important preparative method is the reaction of alkylmagnesium halides with phosphoryl, phosphonyl or phosphinyl halides (6.112-6.114). 

Phosphonic (phosphonyl) halides and phosphinic (phosphinyl) halides (6.177) may be obtained from the corresponding phosphonic and phosphinic acids by the action of PCI5 or SOCI2. 

Phosphonyl and phosphinyl halides may be obtained from halophosphoranes by limited hydrolysis (6.187, 6.188), by bubbling sulphur dioxide through a solution or suspension in an inert solvent (6.189), or by reaction with a carboxylic acid (6.190). 

The addition of phosphorus pentachloride to alkenes and alkynes yields complexes of the type RPClj PClg, which, when treated with sulphur dioxide, will give phosphonyl chlorides (6.197). Hydrolysis of the aluminium trichloride complexes (6.151) and (6.152) will also give phosphonyl or phosphinyl halides (6.198). 

The lower molecular weight phosphonyl and phosphinyl halides are colourless liquids which fume in air. They hydrolyse easily to phosphonic and phosphinic acids, and react with alcohols to give the corresponding esters (6.199, 6.200). Their reactivity decreases as the size of the group R is increased. 

Reaction of phosphinyl halides with metal cyanates yields very reactive cyanate derivatives. 

Phosphinic acids or their sodium salts can be obtained from the action of NaOH on some tertiary phosphine oxides (6.122,6.124) or by the hydrolysis of phosphinyl halides (6.200). 

M. Fild and R. Schmutzler, Phosphonyl and phosphinyl halides, J.I.G. Cadogan, Organophosphorus Reagents in Organic Synthesis, Vol. 4, Academic Press, London, 1979. 

Under anhydrous conditions, phosphinothioUc esters are converted by chlorine to phosphinyl halides, bnt under aqueous conditions, phosphinic acids are obtained directly. 

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