Chemistry An Asian Journal 2013-05-01

Synthesis of optically enriched spirocyclic benzofuran-2-ones by bifunctional thiourea-base catalyzed double-Michael addition of benzofuran-2-ones to dienones.

Xin Li, Chen Yang, Jia-Lu Jin, Xiao-Song Xue, Jin-Pei Cheng

Index: Chem. Asian J. 8(5) , 997-1003, (2013)

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Abstract

A highly enantioselective catalytic double-Michael addition reaction of substituted benzofuran-2-ones with divinyl ketones promoted by readily accessible tertiary amine-thiourea Cinchona alkaloids has been developed. A number of optically enriched spirocyclic benzofuran-2-ones were prepared in very good yields (up to 99 %), diastereoselectivities (up to 19:1 d.r.), and very good enantioselectivities (up to 92 % ee). Density functional theory (DFT) calculations were performed to investigate the origin of stereoselectivity.Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.