STEREOSELECTIVE SYNTHESIS OF VINYLCYCLOPROPANES FROM 2-PHENYLSULFONYL-1,3-CYCLOHEXADIENES AND KETONE ENOLATES OR NITRILE ANION

Michael addition of ketone enolates to 2-(phenylsulfonyl)-1,3-cyclohexadienes and subsequent cyclization affords vinylcyclopropanes in a highly stereoselective manner. In this process the enolate anion of the adduct displaces the allylic phenylsulfonyl group. The analogous reaction between the anion of benzyl cyanide and 2-(phenylsulfonyl)-1,3-cyclohexadiene afforded the corresponding vinylcyclopropane. An attempted synthesis of sesquicarene led to the sesquicarene derivative 3,endo-7-dimethyl-exo-7-(4-hydroxy-4-methylpentanoyl)-2-norcarene.