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Synthesis 2001(13): 2035-2039
DOI: 10.1055/s-2001-17713
PAPER
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Total Synthesis of a Beer-Aroma Constituent Based on Enantioconvergent Biocatalytic Hydrolysis of Trisubstituted Epoxides

Andreas Steinreiber, Sandra F. Mayer, Kurt Faber*
Department of Chemistry, Organic and Bio-organic Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
Fax: +43(316)3809840; e-Mail: Kurt.Faber@KFUNIGRAZ.AC.AT;
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Publication History

Received 11 June 2001
Publication Date:
10 August 2004 (online)

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Abstract

A short asymmetric total synthesis of the plant constituent myrcenediol [(R)-1], and (S)-7,7-dimethyl-6,8-dioxabicyclo[3.2.1]octane (2), which is a volatile constituent of the aroma of beer was accomplished via a chemoenzymatic protocol. The key step consisted of a biocatalytic hydrolysis of trisubstituted epoxides bearing olefinic side chains which proceeded in an enantioconvergent fashion, i.e., a single enantiomeric vic-diol was obtained from the racemate in up to 91% ee and 92% isolated yield.

Key words

epoxide hydrolase - enantioconvergent hydrolysis - trisubstituted epoxide - beer-aroma

15

Since the biocatalytic hydrolysis of trisubstituted epoxides could proceed in an enantioconvergent fashion (not via kinetic resolution), the general use of E-values for the description of enantioselectivities is inapplicable.

20

In contrast, mesylation proceeded very slowly.