Ligand exchange reaction of sulfoxides in organic synthesis: A novel method for synthesizing acetylenes and allenes from carbonyl compounds through sulfoxides having a trifluoro-methanesulfonyloxy group on the β-carbon
A novel method for synthesizing acetylenes and allenes from carbonyl compounds is described. Ligand exchange reaction of alkenylsulfoxides having a trifluoromethanesulfonyloxy group on the β-carbon, which were derived from α-alkyl β-ketosulfoxides, with n-BuLi gave disubstituted acetylenes in good yields. In the case of alkenylsulfoxides having both the trifluoromethanesulfonyloxy and aryl groups on
α-Phenylthio-α,β-unsaturated ketones are prepared in fairly good yields on treatment of α-sulfinyl ketone with stannous triflate. α-Phenylthio-α,β-unsaturated cyanides are also prepared from α-sulfinyl cyanides according to the similar procedure.