The first asymmetric Kumada reactions of alkyl electrophiles are described, specifically, cross-couplings of racemic α-bromoketones with aryl Grignard reagents. Several features of this investigation are of interest. First, the couplings proceed at remarkably low temperature (− 40 or− 60° C), which enables the asymmetric synthesis of racemization-prone α- arylketones. Second, dialkyl ketones undergo enantioselective coupling in good ee and ...
