(Trimethylsilylmethyl) Tributyltin. Improved Synthesis of (Trimethylsilylmethyl) - Triphenyltin via Transmetalation

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Abstract
Several projects under investigation in our laboratory require trimethylsilylmethyl-substituted organostannanes as reagents. Although delivery of tin to substrate may often be accomplished with highly nucleophilic organotin anions, in our hands preparation of (trimethylsilylmethyl) triphenyltin (3) by reaction of triphenyltinlithium (1)2 and chloromethyltrimethylsilane (2) is rather capricious and attended by a number of side products. An alternative mode for the synthesis of 3, utilizing an electrophilic tin species, would couple a trimethylsilylmethylmetal (5a,b) and a triphenyltin halide. Although 3 has been prepared in modest yield (62%) from this approach, we sought to avoid the somewhat cumbersome synthesis of the Grignard reagent 5b associated with this procedure.3 Recent reports from our laboratory have demonstrated (trimethylsilylmethy1)tributyltin (4) to be a convenient in-situ precursor of trimethylsilylmethyllithium (5a) via transmetalation with n-butyllithium. Significantly, yields of olefins from Peterson olefination of aldehydes and ketones or β-ketosilanes from carboxylic acids, acid chlorides or esters employing this technique rival, if not surpass, reported values.4,5