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Synfacts 2009(1): 0091-0091  
DOI: 10.1055/s-0028-1087424
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart ˙ New York

Enantioselective [3+2] Cycloadditions of Azomethine Ylides and Nitroolefins

Contributor(s): Benjamin List, Olga Lifchits
J. Xie, K. Yoshida, K. Takasu, Y. Takemoto*
Kyoto University, Japan
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Publication History

Publication Date:
18 December 2008 (online)

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Significance

Takemoto and colleagues applied their recently developed chiral thiourea catalyst 1 (see Reviews below) to a formal [3+2] cycloaddition of azomethine ylides and nitroolefins. This one-pot reaction proceeds via an enantioselective Michael addition followed by a highly diastereoselective aza-Henry reaction to afford functionalized pyrrolidines in good yields and high er values of up to 96:4. The H-bonding catalysis by thiourea 1 is enhanced in the second step by trifluoroethanol additive.

Reviews: H. Miyabe, Y. Takemoto Bull. Chem. Soc. Jpn. 2008, 81, 785-795; Y. Takemoto Org. ­Biomol. Chem. 2005, 3, 4299-4306.