Aminals, which are used as protecting groups in syntheses and are part of many biologically active compounds, are normally prepared from aldehydes and diamines under conditions that remove water in order to shift the equilibrium to the side of the aminal. Here we report for the first time that aminals can be prepared and isolated in pure water without a catalyst in high yield and purity. (C) 2004 Elsevier Ltd. All rights reserved.
Imidazolinium salts as catalysts for the aza-Diels–Alder reaction
作者:Václav Jurčík、René Wilhelm
DOI:10.1039/b415023f
日期:——
Various easily accessible imidazolinium salts have been found to be capable of catalysing an aza-DielsâAlder reaction with a range of imines and Danishefsky's diene, giving the desired products in good to excellent yields. The influence of the counter-anions on the reactivity has been explored. These salts could contribute to the field of metal-free catalysis/organocatalysis.