Recent progress in selective additions of organometal reagents to carbonyl compounds

Carbon-carbon bond forming reactions are simple and direct methods for synthesizing the various skeletons and the diverse structures of organic compounds. Even 100 years after the discovery of the Grignard reaction, organomagnesium, organolithium, and organoaluminum remain popular for carbon-carbon bond formation reactions in modern organic chemistry. Moreover, asymmetric alkyl- or aryl-additions to carbonyl compounds with organometal reagents is attractive due to the enantioselective synthesis of chiral secondary alcohols, which sharply contrasts the enantioselective reduction of carbonyl compounds. Herein, we review recent progress in the selective addition to carbonyl compounds with organometal reagents, particularly Li, Mg, and Zn from both a classic viewpoint using metal ate complexes and from a catalytic enantioselective viewpoint using new chiral ligands.