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Communication | Special issue | Vol 46, No. 1, 1997, pp.27-30
Published online, 1st January, 1970
DOI: 10.3987/COM-96-S4
An Enantioselective Synthesis of Natural (-)-Huperzine A via Cinchona Alkaloids-promoted Asymmetric Michael Reaction

Satoru Kaneko, Toshiharu Yoshino, Tadashi Katoh, and Shiro Terashima*

*Sagami Central Research Center, Hayakawa, Ayase, Kanagawa 252-1193, Japan

Abstract

An enantioselective synthesis of natural (-)-huperzine A (1) was achieved by a method featuring the Cinchona alkaloids-promoted asymmetric Michael reaction. Employing (-)-cinchonidine as a chiral catalyst, the asymmetric Michael reaction gave 64% ee of the product. The optically pure (+)-9 (>99% ee) obtained by recrystallization was convened to (-)-1.