Organocatalytic anti-Mannich and syn-Aldol Reactions of α-Hydroxy Ketones

Significance

Here the authors report enantio­selective anti-Mannich and syn-aldol reactions of α-hydroxy ketones catalyzed by primary amine-containing amino acids. While catalysts 1 and 3 have been found to be effective for the anti-Mannich reaction, catalysts 2 and 3 have been found to be efficient for syn-aldol reaction. With 20 mol% of catalyst 1 or 3, high diastereoselectivities (2:1 to >19:1) and enantioselectivities (er = 77:23 to 99:1) are obtained for three-component anti-Mannich reaction of different aromatic aldehydes. Similar diastereoselectivities (dr = 3:1 to 18:1) and enantio­selectivities (er = 90:10 to 99:1) are obtained for syn-aldol reaction of different aromatic aldehydes with catalyst 2 or 3.