Simple synthesis of sandalwood odorant rac‐Osyrol^® and its ethoxy homologue

Abstract

rac-Osyrol® (3,7-dimethyl-7-methoxyoctane-2-ol), a commercially important sandalwood odorant has been prepared from dihydromyrcene in three steps. The key steps in the synthesis are the epoxidation of terminal double bond using urea hydrogen peroxide (UHP) and regioselective reduction of epoxide using Vitride®. The same strategy has been applied to the synthesis of its ethoxy homologue.

Selective palladium nanoparticles-catalyzed hydrogenolysis of industrially targeted epoxides in water

“…Promisingly, the EDMO was hydrogenated in the industrially targeted Florsantol® with a complete selectivity and the catalyst could be recycled after reaction under optimized conditions. A preliminary scale-up up to 40 g of substrate was successfully carried out, showing the potential of the process reported herein as a sustainable alternative to the Vitride process [24] for this sought-after fragrance. A mechanism for the hydrogenolysis of epoxides was proposed, corroborated by deuterium labelling experiments.…”

“…2-Phenylethanol, obtained from styrene oxide, is a key ingredient of perfumes or soaps owing to its faint but lasting odor of rose petals, as well as in antiseptic creams and deodorants due to its bacteriostatic and antifungicidal properties [23]. The production of the industrially targeted Florsantol®, a soughtafter sandalwood odorant also known as Osyrol [24], was investigated via this biphasic substratewater process on a multigram scale in collaboration with the "Dérivés Résiniques et Terpéniques" (DRT) company (Castets, France). were obtained from Aldrich and were used without further purification.…”

From Pine to Perfume

“…[27] Alkali hydrides described in literature are potassium borohydride [22,23] or Vitride  (Scheme 11). [21]…”

“…Due to the susceptibility of the diene motif, myrcene (15) storage must be of short duration (≤6 months). (20), Florsantol ® (21), Iso E Super ® (22), Helvetolide ® (23) and Romandolide ® (24) 2.4.1 Dihydromyrcenol (20) Dihydromyrcenol is obtained from 3,7-dimethyl-1,6-octadiene (2) either by addition of formic acid and subsequent saponification of dihydromyrcenyl formate [17] or by direct hydration with concentrated aqueous sulphuric acid at low temperature (Scheme 10). [18] This ingredient is one of the biggest fragrance volume drivers.…”

“…Epoxidation of the residual double bond is carried out either with peracetic acid alone, [20] peracetic acid generated in situ from the urea/hydrogen peroxide + acetic anhydride complex [21] or with hydrogen peroxide in presence of phosphotungstic acid and a phase transfer catalyst. [22,23] Reduction of the epoxide ( 26) is performed either by hydrogenation or with alkali hydrides.…”