Chemoselective Reactions of Citral: Green Syntheses of Natural Perfumes for the Undergraduate Organic Laboratory

Abstract

Chemoselectivity is a central concept in organic synthesis and may be readily appreciated in the context of the fragrant, polyfunctional natural product citral. We describe three single-step reactions students may perform on citral to synthesize other natural perfumes: citronellal, geraniol, nerol, or epoxycitral. Each of the reactions uses a simple catalyst and results in a crude product that may be analyzed directly. Hazards and waste are kept to a minimum. Product characterization may include thin-layer chromatography, NMR and IR spectroscopy, GC−MS, and smell. These reactions are chemoselective, biomimetic, and illustrate several principles of green chemistry.