Stereodivergent Synthesis of Enantioenriched γ‐Butyrolactones Bearing Two Vicinal Stereocenters Enabled by Synergistic Copper and Iridium Catalysis

Abstract

AbstractBy virtue of a fundamentally new reaction model of azomethine ylide serving as a two‐atom synthon, we present the first example of stereodivergent preparation of γ‐butyrolactones via synergistic Cu/Ir‐catalyzed asymmetric cascade allylation/lactonization, and all four stereoisomers of γ‐butyrolactones bearing two vicinal stereocenters are accessible with excellent diastereoselective and enantioselective control. The chiral IrIII‐π‐allyl intermediate was separated and characterized to understand the origin of the regio‐ and stereoselectivity of the initial C−C bond formation process. Control experiments shed some light on the catalyst/substrate and catalyst/catalyst interactions in this dual catalytic system to rationalize the related kinetic/dynamic kinetic resolution process with different catalyst combinations. The enantioenriched γ‐butyrolactone products were converted into an array of structurally complex chiral molecules and organocatalysts that were otherwise inaccessible.