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
原位生成的 (R)- 或 (S)-BINOLAM-AlCl 作为双功能催化剂促进醛的对映选择性氰基烷氧基羰基化。该反应的范围很广,收集到的机械证据表明间接过程的干预涉及 HCN 对映选择性氢氰化,然后是 O-烷氧基羰基化。所得的 O-烷氧基羰基氰醇被证明是合成的重要手性构件。因此,化学选择性水解可用于提供对映体富集的 β-羟基酯或酸,或者产生 O-甲氧基羰基 β-羟基酸、酯或酰胺。此外,对映纯的氰基碳酸酯可以通过氢化铝锂还原转化为 β-氨基醇。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)