Asymmetric [2,3]-Wittig Rearrangement: Synthesis of Homoallylic, Allenylic, and Enynyl α-Benzyl Alcohols.

A highly stereoselective [2,3]-Wittig rearrangement of allylic and propargylic ethers controlled by a chiral sulfoxide moiety is presented. The activation provided by the sulfoxide at the remote ortho position allows the rearrangement of less-activated and unexplored benzylic carbanions. Thus, this general methodology gives access to the asymmetric synthesis of homoallylic, enynyl, and allenylic α-benzyl alcohol derivatives.