Mechanistic and synthetic aspects of the reaction of alkyl esters of phosphorus with trimethylstannyl halides

The reaction of trimethylstannyl halides with trialkyl phosphates has been studied. The results are interpreted in terms of a mechanism involving a trimethylstannyloxyphosphonium salt intermediate. The much lower reactivity of the stannyl halides compared with their silicon analogs is explained by the lower ionization of the stannyl halide phosphate complexes and the unfavourable direction of the decomposition of the phosphonium salt intermediate. The reaction may be useful in synthesis of phosphates containing only one O-stannyl group, which can be used in generation of the acid function or replaced in reactions with compounds containing active halogen.