Asymmetric aldol condensation in an ionic liquid-water system catalyzed by (S)-prolinamide derivatives.
作者:A. S. Kucherenko、D. E. Syutkin、S. G. Zlotin
DOI:10.1007/s11172-008-0092-x
日期:2008.3
Asymmetric aldol reaction of unmodified aldehydes with ketones catalyzed by 1(R),2(R)-bis((S)-prolinamido)cyclohexane (1) or (Rax)-2,2′-bis((S)-prolinamido)-1,1′-binaphtyl (2) proceeds with high yield (68–99%) and diastereoselectivity (dr ≥ 75/25) in the system (1-butyl-3-methylimida-zolium) tetrafluoroborate ([bmim][BF4])-water. The dependence of ee of the dominating anti-diastereomer of aldol on the percentage of water has a maximum at 50 vol.%. Catalyst 1 can be recycled 5 times without losses in the aldol yield, dr and ee.
在 1(R),2(R)-双((S)-脯氨酰胺基)环己烷 (1) 或 (Rax)-2,2′- 双((S)-脯氨酰胺基)-1、1′-联萘(2)在(1-丁基-3-甲基咪唑)四氟硼酸盐([bmim][BF4])-水体系中以高产率(68-99%)和非对映选择性(dr ≥ 75/25)进行。醛醇的主要反非对映异构体的ee值与水的百分比的关系在 50 vol.%时最大。催化剂 1 可以循环使用 5 次,而不会损失醛醇产率、dr 和 ee。