Enantioselective synthesis of O-methoxycarbonyl cyanohydrins:: Chiral building blocks generated by bifunctional catalysis with BINOLAM-AlCI

(R)- or (S)-BINOLAM-AlCl, generated in situ, work as bifunctional 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 can thus be directed either to provide enantioenriched beta-hydroxy esters, or acids, or instead to give O-methoxycarbonyl beta-hydroxy acids, esters, or amides. In addition, the enantiopure cyanocarbonates can be converted into beta-amino alcohols by reduction with lithiumaluminium hydride. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).