Allylic Lithium Oxyanionic Directed and Facilitated Simmons−Smith Cyclopropanation:  Stereoselective Synthesis of (±)-cis-Sabinene Hydrate and a Novel Ring Expansion

[reaction: see text] The lithium salts of acid-sensitive allyl alcohols, which themselves decompose during Simmons-Smith cyclopropanation, undergo smooth cyclopropanation in the usual stereocontrolled manner. This concept is applied to the most efficient 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 salts than for the allyl alcohols themselves.