Rh‐Catalyzed [4+2] Annulation of 4‐Alkynals with Isocyanates and Its Application to the Parallel Kinetic Resolution of Unfunctionalized 4‐Alkynals

Abstract

Enantioenriched 2-alkylideneglutarimides and cyclopentenones are prepared by parallel kinetic resolution of 3-substituted 4-alkynals with a cationic RhI/(S)-segphos catalyst system. This is an attractive route to the above-mentioned products given the one-step access to 4-alkynals from readily available terminal alkynes.