Chiral Sulfoximine Mediated Cobalt‐Catalyzed Atropselective C−H Annulation of Ynamides.

An achiral Cp*Co(III)‐catalyzed enantioselective C−H activation/annulation of chiral sulfoximine‐enabled thioamides with ynamides is presented herein. This method successfully synthesizes axially chiral five‐membered 2‐amidoindenones with good enantiocontrol. Interestingly, the annulation with chiral oxazolidone‐containing ynamides could provide a separable mixture of diastereomers (up to ~10 : 1 dr). Moreover, enantiopure sulfoximines could be recovered with ~99 % purity, making this method practical. DFT studies show valuable insight into the mechanism and origin of asymmetric induction. [ABSTRACT FROM AUTHOR]