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Synfacts 2008(2): 0176-0176  
DOI: 10.1055/s-2007-992485
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Enantioselective [2+2] Cycloaddition with Oxazaborolidine Catalysts

Contributor(s): Mark Lautens, Praew Thansandote
E. Canales, E. J. Corey*
Harvard University, Cambridge, USA
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Publication History

Publication Date:
23 January 2008 (online)

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Significance

The authors have reported the utility of an aluminum oxazaborolidine catalyst developed in their laboratory for the catalytic enantio­selective [2+2] cycloaddition of enol ethers with trifluoroethyl acrylate. Two types of enol ethers were tested, with the TIPS-protected enol ethers having the greater endo selectivity compared to the TBS-protected analogues. The products are previously unknown chiral cyclobutanes and can be transformed into enones in four steps.