Stereoselective Synthesis of Substituted γ-Butyrolactones by the [3 + 2] Annulation of Allylic Silanes with Chlorosulfonyl Isocyanate: Enantioselective Total Synthesis of (+)-Blastmycinone

[structure: see text]. A stereoselective synthesis of gamma-butyrolactones by the [3 + 2] annulation of allylic silanes with N-chlorosulfonyl isocyanate (CSI) was developed. An enantioselective total synthesis of (+)-blastmycinone was accomplished using this annulation as the key step.