Sulfur‐Directed Construction of Vinyl Cyclopropanes from 1,3‐Dienes

ABSTRACT The stereoselective cyclopropanation of 1,3‐dienes remains a long‐standing challenge in the preparation of vinyl cyclopropanes (VCPs) due to the intrinsic electronic and steric bias of the diene scaffold. We report a sulfur‐directed strategy that enables highly site‐ and diastereoselective cyclopropanation of S ‐substituted 1,3‐dienes with diazo reagents under Cu‐catalyzed reaction conditions. This unprecedented approach overrides the innate reactivity of the 1,3‐diene through a thioether‐directed reaction mode, providing rapid access to a broad library of highly functionalized S ‐VCPs obtained as single regio‐ and diastereomers. Preliminary mechanistic studies indicate a pericyclic cascade involving a 6π‐electrocyclization and a [2,3]‐sigmatropic rearrangement and postmodifications permit streamlined access to complex VCPs that remain inaccessible through conventional cyclopropanation techniques.