RCM Helicene Synthesis

Significance

A new procedure for the synthesis of helicenes by ring-closing metathesis of olefin-functionalized binaphthols is reported. Two different sets of conditions were explored. The first utilizes Grubbs 2^nd generation catalyst (1) with microwave heating for 25-120 min. The second uses catalyst 2 with conventional heating at 40 °C for 24 h. These conditions were tested on a variety of substituted binaphthols with isolated yields ranging from 22-93%. In all instances, with the exception of the parent compound, the microwave conditions provided superior yields.