Enantioselective Carbon−Carbon Bond Formation via SN2‘ Displacements of Acyclic Allylic Mesylates1

The copper-mediated S(N)2' displacement of enantiomerically pure allylic mesyloxy vinyl sulfoxides takes place with high yields and stereoselectivities. In these adducts, the newly created chiral center is adjacent to a vinyl sulfoxide functionality which should allow for subsequent chirality transfer operations. Alternatively, enantiopure alkenyl sulfones and alkenes bearing an allylic stereocenter are readily available from these adducts with high geometric control. The S(N)2' displacements of structurally related mesyloxy sulfides and sulfones with organocuprates have been examined. From a single enantiomer at the allylic alcohol position, the absolute configuration of the new chiral center may be controlled by adjusting the oxidation level on sulfur.