Synthesis 2008(14): 2183-2190  
DOI: 10.1055/s-2008-1067151
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Diastereoselective Cyclopropanation of Electron-Deficient Alkenes via Metal Glycal Carbenes

Frank Otto, Karl Heinz Dötz*
Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
Fax: +49(228)735813; e-Mail: doetz@uni-bonn.de;
Further Information

Publication History

Received 18 April 2008
Publication Date:
18 June 2008 (online)

Abstract

Silyl- and isopropylidene-O-protected chromium glucal and galactal carbenes have been synthesized from their glycal precursors according to the Fischer route. NMR studies indicate a preferred 5 H 4 or 4 H 5 conformation, depending on the nature of the protective group and the configuration at C-4. The complexes with glycal carbenes have been applied to the diastereoselective cyclopropanation of methyl crotonate and γ-crotonolactone.