Synthesis and Mechanistic DFT Studies of Arylhimachalene via Bromination of Himachalenes

Abstract

Background: Arylhimachalene is a sought-after natural sesquiterpene, found in small quantities in the essential oil of Atlas cedar (Cedrus atlantica). Herein, we present a simple and efficient method for synthesizing this molecule, involving the bromination of a mixture of himachalene (the principal constituent of the same oil) and a mechanistic study based on density functional theory (DFT) calculations. Methods: The synthesis of arylhimachalene was carried out by bromination using Br2/CH2Cl2. The resulting product was isolated by silica gel column chromatography and characterized by NMR spectroscopy. Results: The treatment of the himachalene mixture with bromine led to the formation of arylhimachalene, as well as other rearrangement products catalyzed by in situ-formed bromic acid. Conclusion: This study highlights the development of a simple method for synthesizing a natural molecule of interest, serving as a basis for numerous scientific studies, and also includes a mechanistic study of this synthesis.