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Synthesis 2002(4): 0515-0522
DOI: 10.1055/s-2002-20967
PAPER
© Georg Thieme Verlag Stuttgart · New York

A General Approach to the Asymmetric Synthesis of Lignans: (-)-Methyl Piperitol, (-)-Sesamin, (-)-Aschantin, (+)-Yatein, (+)-Dihydroclusin, (+)-Burseran, and (-)-Isostegane

Dieter Enders*, Vivien Lausberg, Giuseppe Del Signore, Otto Mathias Berner
Institut für Organische Chemie, Rheinisch-Westfälische Technische Hochschule, Professor-Pirlet-Str. 1, 52074 Aachen, Germany
Fax: +49(241)8092127; e-Mail: enders@rwth-aachen.de;
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Publication History

Received 22 January 2002
Publication Date:
28 July 2004 (online)

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Abstract

A highly efficient, diastereo- and enantioselective route was developed to access a great variety of lignans. The asymmetric synthesis of the 2,3-disubstituted γ-butyrolactones 9a-c could be improved in the case of aldol reactions by employing 2.2 equivalents of LiCl as an additive to provide, after purification, highly diastereo- and enantioenriched starting materials for the synthesis of the furofuran lignans (-)-methyl piperitol, (-)-sesamin, and (-)-aschantin. Furthermore, the γ-butyrolactone 15 was converted into dibenzylbutyrolactone lignan (+)-yatein, the dibenzylbutandiol type (+)-dihydroclusin, the tetrahydrofuran type (+)-burseran, and the dibenzocyclooctadiene type (-)-isostegane.

Key words

α-amino nitriles - asymmetric synthesis - chiral auxiliary - lignans - aldol reaction