ipso-Bromination of tert-butylcalix[4]arenes

Abstract

The ipso-bromination of calix[4]arenes using bromine has been investigated and provides a direct method to tetra-bromocalix[4]arene in a single step in excellent yield (>90%). The method is also applicable to directly forming tribromocalix[4]arene in appreciable amounts (>60%). It was found during this study that a number of important reaction variables were very important for success, namely exclusion of light, temperature control, purity of starting material, solvent used and rate of bromine addition.