Methyllithium-promoted Wittig rearrangements of alpha-alkoxysilanes.

ABSTRACT

[formula see text] The Wittig rearrangements of alpha-alkoxysilanes, promoted by the action of methyllithium were studied. Depending on both the substrate and reaction conditions employed, [2,3]-, [1,2]-, or [1,4]-Wittig rearrangements can be realized. These rearrangements were shown to be initiated by either Si/Li exchange or deprotonation alpha to the silane. Furthermore the sigmatropic shifts can often be followed by other synthetically useful in situ chemical events.