The Guaiol Color Reaction

Abstract

The common and biogenetically important sesquiterpene guaiol yields a deep purple color when treated with electrophilic bromine reagents. This interesting color reaction was observed over fifty years ago, but the chemistry of this process has not been investigated. Herein, we present the chemistry of the guaiol color reaction.

Natural sesquiterpenoids

“…325 The chemistry of the deep purple colour formed when guaiol is treated with electrophilic bromine reagents has been investigated. 326 Formal total syntheses of the trinorguaiane sesquiterpenes (Ϫ)-(S,S )-clavukerin A and (ϩ)-(R,S )-isoclavukerin, 327 and of the racemates (±)-clavukerin A and (±)-isoclavukerin 328 have been reported. An efficient synthesis of racemic 7-epi-βbulnesene has been achieved.…”