Enantioselective cyanoformylation of aldehydes using a recyclable dimeric cinchonidine ammonium salt as an organocatalyst
作者:Rafael Chinchilla、Carmen Nájera、Francisco J. Ortega
DOI:10.1016/j.tetasy.2008.01.011
日期:2008.2
ammonium salt is used as a chiral organocatalyst in the enantioselective addition of alkyl cyanoformates to aldehydes in the presence of substoichiometric amounts of triethylamine. Quantitative yields and enantioselectivities up to 88% ee for the corresponding (R)-O-methoxycarbonyl cyanohydrins are obtained using only 1 mol % organocatalyst loading and working at 10 °C. The organocatalyst can be almost
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.