抗的-选择性曼尼希反应ñ - p -甲氧基苯基(PMP)与未改性的醛或酮-保护的α-iminoglyoxylate得到有效利用4-氨基硫脲脯氨醇催化叔-butyldiphenylsilyl醚。反应导致高收率(高达94%),出色的非对映异构和对映选择性(高达98%de和> 99%ee)的手性β-氨基羰基化合物。该研究首次证明,仲胺-硫脲手性有机催化剂可促进未修饰醛或酮与α-亚氨基乙醛酸酯的直接曼尼希型反应。
4-Trifluoromethanesulfonamidyl prolinol tert-butyldiphenylsilyl ether as a highly efficient bifunctional organocatalyst for Michael addition of ketones and aldehydes to nitroolefins
作者:Chao Wang、Chun Yu、Changlu Liu、Yungui Peng
DOI:10.1016/j.tetlet.2009.02.211
日期:2009.5
4-Trifluoromethanesulfonamidyl prolinol tert-butyldiphenylsilyl ether bifunctionalorganocatalyst 3a is a highly efficient catalyst for the asymmetric Michaeladdition reactions of ketones and aldehydes to nitrostyrenes, leading to syn-selective adducts with excellent yields (>99%), high diastereoselectivities (up to 99:1 dr) and excellent enantioselectivities (up to 99% ee). Control experiments suggested that the
Anti-selective Mannich reactions of N-Boc and N-Cbz protected imines with unmodified aldehydes proceeded smoothly under the catalysis of a secondary amine–thiourea catalyst, which led to high yields (70%–95%) and excellent enantioselectivity (up to 96 ∶ 4 dr and >99% ee) under conventional organic synthetic operations.