Synthesis 2006(3): 471-479  
DOI: 10.1055/s-2006-926276
PAPER
© Georg Thieme Verlag Stuttgart · New York

Highly Diastereoselective Sequential Michael-Aldol Reactions of Methyl 2-Chloro-2-cyclopropylideneacetate with Grignard Reagents and Aldehydes [1]

Suryakanta Dalaia, Michael Limbacha, Ligang Zhaoa, Markus Tamma, Madhumati Sevvanab, Viktor V. Sokolova, Armin de Meijere*a
a Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
Fax: +49(551)394795; e-Mail: ameijer1@gwdg.de;
b Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
Further Information

Publication History

Received 18 May 2005
Publication Date:
11 January 2006 (online)

Abstract

Grignard reagents, especially isopropylmagnesium chloride, smoothly undergo Michael addition onto methyl 2-bromo- and 2-chloro-2-cyclopropylideneacetate (1-Cl), and the thus formed magnesium enolates are particularly efficiently trapped with aromatic aldehydes. This one-pot reaction provides highly substituted chlorohydrines, mostly in high yields (10 out of 18 examples with 72-92%) and as pure (2S*,3R*)-diastereomers (anti-aldols). These chlorohydrines can be transformed to Darzens-type α,β-epoxyesters in good yields, as demonstrated for one example.

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Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited as supplementary publication no. CCDC-268832 with the Cambridge Crystallographic Data Centre. Copies of the data can be obtained free of charge on application to The Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [Fax: +44 (1223)336033; E-mail: deposit@ccdc.cam.ac.uk].