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Synfacts 2007(12): 1283-1283  
DOI: 10.1055/s-2007-991368
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Enantioselective Carbonyl-Ene Reaction with a Modified Salen Catalyst

Contributor(s): Mark Lautens, Frédéric Ménard
G. E. Hutson, A. H. Dave, V. H. Rawal*
University of Chicago, USA
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Publication History

Publication Date:
22 November 2007 (online)

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Significance

The authors found that modifying a salen ligand with two bulky silyl groups (TIBS) imparts a significant twist to the nearly planar structure of common salen ligands. Although the asymmetric carbonyl-ene reaction has been studied with many metal catalysts (Ti, Cu, Sc, Cr), the alkene was generally activated as an enol ether or as an enamine. With the modified salen-Co complex 1, even unactivated alkenes react with high levels of selectivity to afford allylated alcohol products. With pyridine-2-carbaldehyde, the first example of a monocarbonyl reacting with an unactivated alkene was demonstrated to give excellent ee (>99%).