A New Entry to Asymmetric Synthesis of Optically Active α,γ-Substituted γ-Butyrolactones, Using a Carbohydrate Derived Amide as Both a Chiral Auxiliary and a Proton Source

A new entry for the asymmetric synthesis of optically active alpha,gamma-substituted gamma-butyrolactones was developed by using a carbohydrate-derived amide as both a chiral auxiliary and a proton source. Unlike the previously reported examples, the chiral auxiliary employed in this reaction also successfully functioned as a protonating agent. Excellent asymmetric induction could be achieved by this dual stereoselective control in the reaction process.