A Designer Axially Chiral Amino Sulfonamide as an Efficient Organocatalyst for Direct Asymmetric Mannich Reactions of N-Boc-Protected Imines
作者:Taichi Kano、Yukako Yamaguchi、Keiji Maruoka
DOI:10.1002/anie.200805628
日期:2009.2.23
The moderate nucleophilicity of the axially chiral amino sulfonamide (S)‐1 suppresses the problematic side reactions, including aldol reactions, in the asymmetric Mannich reaction of N‐Boc‐protected imines with aldehydes. The corresponding adducts are obtained in good yield and excellent stereoselectivity (see scheme; Boc=tert‐butoxycarbonyl, Tf=trifluoromethanesulfonyl).
轴向手性氨基磺酰胺(S)-1的中等亲核性抑制了N-Boc保护的亚胺与醛的不对称曼尼希反应中有问题的副反应,包括醛醇缩合反应。得到的相应加合物收率高,立体选择性好(参见方案; Boc =叔丁氧羰基,Tf =三氟甲磺酰基)。