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Synfacts 2006(8): 0843-0843
DOI: 10.1055/s-2006-942025
DOI: 10.1055/s-2006-942025
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart · New York
Chiral Diamine-Salts for Catalytic exo-selective Diels-Alder Reactions
T. Kano, Y. Tanaka, K. Maruoka*
Kyoto University, Japan
Further Information
Publication History
Publication Date:
21 July 2006 (online)
![](https://www.thieme-connect.de/media/synfacts/200608/lookinside/thumbnails/10.1055-s-2006-942025-1.jpg)
Significance
A highly exo-selective and enantioselective organocatalytic Diels-Alder (DA) reaction has been developed. Various α,β-unsaturated aldehydes 2 undergo DA reaction with cyclopentadiene (3) when N-methylaniline derivatives and protonic acids are used as catalysts. N-methylaniline-TsOH itself gave exo-4 (R = Ph) in 75% yield and 2.2:1 selectivity. Exceedingly high exo-selectivities (from 6:1 to >20:1) could be obtained when catalyst 1 together with p-toluenesulfonic acid or related chiral diamine salts at -20 °C with α,α,α-trifluorotoluene as solvent were used. Moderate to high enantioselectivities (27-92%) have been obtained. The use of salts derived from primary amines did not yield any products.