Abstract

The straightforward synthesis of calix[4]crown derivatives in excellent yields under non-diluted reaction conditions is described. The reactions proceed smoothly at ordinary temperature and substrate concentrations of up to 1 M. Theoretical calculations on the reaction intermediates indicate that preorganization originating from the coordination of oxygen atoms to sodium ions plays an important role in the reaction

Keywords: calix[4]crown, calix[4]arene, cyclization, conformation, reaction mechanism