Terpene cyclization catalysis with a functional cavitand: driving selectivity through precise molecular recognition

Abstract

A three-walled self-folding cavitand receptor derived from resorcin[4]arene featuring phenol groups near the confined space catalyzes the cyclization reaction of nerol, using HCl as co-catalyst. In contrast to terpene cyclization reactions mediated by other synthetic hosts, the process reported herein is substrate specific, provides very high selectivity towards cyclization products, and delivers limonene—a thermodynamically disfavored product—as the major compound. The observed acceleration, turnover and unique selectivity are rationalized on the basis of precise molecular recognition phenomena, supported by NMR studies and DFT calculations.