Enantioselective Synthesis ofO-Methoxycarbonyl Cyanohydrins: Chiral Building Blocks Generated by Bifunctional Catalysis with BINOLAM-AlCl
作者:Alejandro Baeza、Jesús Casas、Carmen Nájera、José M. Sansano、José M. Saá
DOI:10.1002/ejoc.200500939
日期:2006.4
catalysts in promoting the enantioselective cyanoalkoxycarbonylation of aldehydes. The reaction is wide in scope and the mechanistic evidence gathered suggests the intervention of an indirect process involving enantioselective hydrocyanation by HCN, followed by O-alkoxycarbonylation. The resultant O-alkoxycarbonyl cyanohydrins are shown to be important chiral building blocks for synthesis. Chemoselective hydrolysis
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 ammoniumsalts as an organocatalyst in this transformation was also explored.