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Synfacts 2007(6): 0648-0648  
DOI: 10.1055/s-2007-968563
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart · New York

Brønsted Acid Catalyzed anti-Selective Direct Mannich Reaction

Contributor(s): Benjamin List, Subhas Chandra Pan
Q.-X. Guo, H. Liu, C. Guo, S.-W. Luo, Y. Gu, L.-Z. Gong
University of Science and Technology of China, Hefei; Chengdu Institute of Organic Chemistry; Graduate School of Chinese Academy of Sciences, Beijing, P. R. of China
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Publication History

Publication Date:
22 May 2007 (online)

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Significance

Chiral phosphoric acid catalyzed anti-selective direct Mannich reactions of cyclic ketones with aromatic amines have been developed. Catalysts 1 or 2 have been identified as the best catalysts for these reactions. With 0.5-2 mol% of catalyst 1 or 2 good to high diastereoselectivities (dr = 77:23 to 98:2) and high enantioselectivities (er = 88:12 to 99:1) are obtained for different cyclic ketones. In addition, the authors have also reported direct asymmetric Mannich reactions of acyclic ketones. With 5 mol% of catalyst 3 or 4 moderate to good yields (42-76%) and good enantioselectivities (er = 85:15 to 93:7) are obtained for different acyclic ketones.