Development of catalytic asymmetric intramolecular cyclopropanation of α-diazo-β-keto sulfones and applications to natural product synthesis

The catalytic asymmetric intramolecular cyclopropanation (CAIMCP) of α-diazo-β-keto sulfones developed in our laboratory and applications to the total synthesis of natural products are described. CAIMCP features (a) a wide applicability, not only to the preparation of bicyclo[n.1.0]alkanes and tricyclo[4.n.0.0]alkenes, but also to the enantioselective total synthesis of natural products, (b) the formation of highly crystalline products, which facilitate the production of enantiomerically pure synthetic intermediates, and (c) the generation of products with a variety of functionalities, such as cyclopropane, ketone, and sulfone, beneficial to the total synthesis of natural products.