Synfacts 2009(2): 0117-0117  
DOI: 10.1055/s-0028-1087603
Synthesis of Natural Products and Potential Drugs
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of Estrone Methyl Ether

Contributor(s): Philip Kocienski
E. Canales, E. J. Corey*
Harvard University, Cambridge, USA
Further Information

Publication History

Publication Date:
22 January 2009 (online)

Significance

Canales and Corey report a ­remarkably short and efficient synthesis of estrone methyl ether which exploits a novel N-methyl­oxazaborolidinium cation as a Lewis acid catalyst for an asymmetric Diels-Alder reaction. The paper cites ten further examples all proceeding with excellent yields and ee values. The reactions typically proceed in dichloromethane at -78 ˚C but in the estrone synthesis depicted, the cycloaddition was performed at room temperature. The ee of the adduct D (82%) was raised to 99% by one recrystallization.