Enantioselective Reactions of Donor/Acceptor Carbenoids Derived from α-Aryl-α-Diazoketones

The reaction of a variety of α-aryl-α-diazo ketones with activated olefins, catalyzed by the adamantyl glycine-derived dirhodium complex Rh2(S-PTAD)4, generates cyclopropyl ketones with high diastereoselectivity (up to >95:5 dr) and enantioselectivity (up to 98% ee). Intermolecular C−H functionalization of 1,4-cyclohexadiene by means of carbenoid-induced C−H insertion was also possible with this type of carbenoid.