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Synfacts 2011(10): 1126-1126  
DOI: 10.1055/s-0030-1261118
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart ˙ New York

Asymmetric Mannich Reaction of a HWE Reagent to Afford MBH-Type Products

Contributor(s): Benjamin List, Ji-Woong Lee
D. Zhao, D. Yang, Y. Wang, Y. Wang, L. Wang, L. Mao, R. Wang*
Lanzhou University, P. R. of China and , The Hong Kong Polytechnic University, Hong Kong
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Publication History

Publication Date:
20 September 2011 (online)

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Significance

The authors developed an enantio­selective Mannich reaction of Horner-Wadsworth-Emmons reagent 1. By employing N-acyl pyrrole phosphonate 1, the reaction could be realized in the presence of Takemoto-type organic base 3 as a chiral, bifunctional catalyst. Good to excellent enantioselectivities were observed with in situ generated aromatic imines (er up to 98:2); aliphatic imines, however, gave only moderate enantioselectivity. The corresponding Mannich adducts can be easily transformed into aza-Morita-Baylis-Hillman-type products 4 by treatment with paraformaldehyde. Also, stereo­selective olefination can be achieved by using an appropriate base.