Carbolithiation of S-alkenyl-N-aryl thiocarbamates: carbanion arylation in a connective route to tertiary thiols.

S-alkenyl-N-arylthiocarbamates are formed from allylic alcohols by sigmatropic rearrangement and isomerization or C═C bond cleavage. They undergo carbolithiation with a range of organolithium reagents, generating benzyllithium intermediates in a stereospecific manner which may undergo N to C aryl migration to yield thiocarbamates with tertiary substituents. A simple base-promoted alcoholysis reveals a series of hindered tertiary thiols with branched carbon skeletons.