Enantioselective Synthesis of the Platensimycin Core by Silver(I)‐Promoted Cyclization of Δ6‐α‐Iodoketone

A chiral‐pool‐based synthesis of the platensimycin core was achieved using (S)‐lactic acid as an inexpensive starting material. The cyclohexenone ring was closed in a Mukaiyama–Michael domino sequence, while the quaternary stereocenter was created by a highly stereoselective decarboxylative allylation. The spirobicyclic skeleton was constructed by a RCM reaction. A new silver(I)‐promoted cyclization reaction of Δ6‐ and Δ7‐α‐iodoketones was developed and applied for the pivotal carbon–carbon bond formation. The scope and limitations of this methodology are also presented. Go enantio! Enantioselective synthesis of the platensimycin core was achieved, relying on a chiral‐pool strategy. The Mukaiyama–Michael domino sequence enabled the cyclohexenone ring to be closed diastereoselectively, while the quaternary stereocenter was created by a highly stereoselective decarboxylative allylation. The crucial C−C bond was formed by using a silver(I)‐promoted cyclizations of Δ6‐ and Δ7‐α‐iodoketones (see scheme).