Allylic lithium oxyanionic directed and facilitated Simmons-Smith cyclopropanation: Stereoselective synthesis of (+)-cis-sabinene hydrate and a novelring expansion

[GRAPHICS] The lithium salts of acid-sensitive allyl alcohols, which themselves decomp ose during Simmons-Smith cyclopropanation, undergo smooth cyclopropanation in the usual stereocontrolled manner, This concept is applied to the most e fficient synthesis of (+)-cis-sabinene hydrate and to the cyclopropanation of the anion of a nonisolable allyl alcohol resulting upon workup in a ring -expanded enone, The cyclopropanations are also faster for the lithium salt s than for the allyl alcohols themselves.