Asymmetric Synthesis of Dihydropyranones via Gold(I)‐Catalyzed Intermolecular [4+2] Annulation of Propiolates and Alkenes

Intermolecular asymmetric gold catalysis involving alkyne activation presents a significant challenge due to its distinct mechanistic mode from other metals. Herein, we report a highly enantioselective synthesis of α,β‐unsaturated δ‐lactones from [4+2] annulation of propiolates and alkenes in upto 95 % ee. Notably, for the desired chiral recognition, the choice of 1,1,2,2‐tetrachloroethane as solvent was found to be crucial. Furthermore, an anionic surfactant (sodium dodecyl sulfate) improved the product selectivity in the divergence of the cyclopropyl gold carbene intermediate. Die enantioselektive [4+2]‐Anellierung von Propiolaten mit Alkenen führt zur Synthese von Dihydropyranonen mit bis zu 95 % ee. Mit der einstufige Synthese können α,β‐ungesättigte δ‐Lactongerüste aus di‐ und trisubstituierten Alkenen sowie aus 1,3‐Dienen effizient erhalten werden.