3-Pyrrolidinecarboxylic Acid for Direct Catalytic Asymmetric anti-Mannich-Type Reactions of Unmodified Ketones
Haile Zhang, Maria Mifsud, Fujie Tanaka,* and Carlos F. Barbas, III*
*The Skaggs Institute for Chemical Biology and the Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, California 92037, Email: ftanakascripps.edu, carlosscripps.edu
H. Zhang, M. Mifsud, F. Tanaka, C. F. Barbas, III, J. Am. Chem. Soc., 2006, 128, 9630-9631.
DOI: 10.1021/ja062950b (free Supporting Information)
Direct catalytic, enantioselective, anti-selective Mannich-type reactions between unmodified ketones and α-imino esters using 5-10 mol % of (R)-3-pyrrolidinecarboxylic acid or (R)-β-proline as catalyst in 2-PrOH at room temperature gave products in good yields with high diastereo- and enantioselectivities.
see article for more examples
A. Cordova, W. Notz, G. Zhong, J. M. Betancort, C. F. Barbas, III, J. Am. Chem. Soc., 2002, 124, 1842-1843.