Chiral Brønsted Acid-Catalyzed Formal α-Vinylation of Cyclopentanones for the Enantioselective Construction of Quaternary Carbon Centers

An enantioselective formal α-vinylation of ketones for the construction of an all-carbon quaternary center was established using the vinylogous Wagner–Meerwein shift through the activation of the leaving group by a chiral phosphoramide as the chiral Brønsted acid catalyst. The present reaction afforded enantioenriched all-carbon quaternary α-vinyl ketones in high yields with high enantioselectivities in most cases. Experimental elucidation of...