Enantioselective cyanoformylation of aldehydes organocatalyzed by recyclable cinchonidine ammonium salts
作者:Rafael Chinchilla、Carmen Nájera、Francisco J. Ortega、Silvia Tarí
DOI:10.1016/j.tetasy.2009.08.007
日期:2009.10
and α,β-unsaturated aldehydes give lower enantioselectivities (up to 60%) in high yields. The observed sense of the enantioselection was always the same, and the organocatalyst was almost quantitatively recovered by ether-promoted precipitation without any loss of activity. The use of resin-supported cinchonidine-derived ammonium salts as an organocatalyst in this transformation was also explored.
在亚化学计量的三乙胺(20 mol%)存在下,通过将氰基甲酸酯对映选择性加成到对映异构体富集的O-甲氧基羰基氰醇中,该醛由二聚蒽基二甲基衍生的辛可尼定铵盐(催化剂负载量为1 mol%)有机催化的醛中。芳族和杂芳族醛通常可提供高对映选择性(最高96%)和相应O的定量收率-甲氧基羰基氰醇,而脂族和α,β-不饱和醛的收率较低(最高60%)。所观察到的对映异构感始终是相同的,并且有机催化剂几乎可以通过醚促进的沉淀定量回收,而不会损失任何活性。还探索了在这种转化中使用树脂负载的可可丁定衍生的铵盐作为有机催化剂。