Asymmetric Nitroallylation of Arylboronic Acids with Nitroallyl Acetates Catalyzed by Chiral Rhodium Complexes and Its Application in a Concise Total Synthesis of Optically Pure (+)-γ-Lycorane

Abstract

[reaction: see text]A new rhodium-catalyzed highly enantioselective nitroallylation of 2-nitrocyclohex-2-enol esters with arylboronic acids is described. A rhodium complex of [RhOH(COD)]2 and optically pure BINAP is the optimal catalyst that provides good yields and high enantioselectivities ranging from 90 to 99% ee for various arylboronic acids at 50 degrees C. A concise total synthesis of optically pure (+)-gamma-lycorane in overall 38% yield was achieved on the basis of this new method.