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

The reaction of a variety of a-aryl-a-diazo ketones with activated olefins, catalyzed by the adamantyl glycine-derived dirhodium complex Rh-2(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.