A Highly Efficient Asymmetric Synthesis of Optically Active α,γ-Substituted γ-Butyrolactones Using a Chiral Auxiliary Derived from Isosorbide

Using an easily accessible and inexpensive chiral auxiliary derived from isosorbide, optically active alpha,gamma-substituted gamma-butyrolactones were obtained in high enantiomeric purity (up to >99% ee for trans) by the SmI(2)-induced reductive coupling of chiral methacrylate 7 with ketones in the presence of (-)-sultam as a proton source.