Applied Catalysis A: General, Vol.502, 271-275, 2015
Heteropoly acid catalyzed cyclization of nerolidol and farnesol: Synthesis of alpha-bisabolol
Heteropoly acid H3PW12O40 is an active and environmentally friendly homogeneous catalyst for the synthesis of alpha-bisabolol, a high-priced and highly demanded ingredient for the fragrance, cosmetic and pharmaceutical industries, starting from more abundant biomass-based sesquiterpenic alcohols. The solvent nature remarkably affects the reaction pathways and product selectivity. In acetone solutions, alpha-bisabolol can be obtained in 55-60% GC yields from nerolidol and 60-70% GC yields from famesol at complete substrate conversions, which are probably the best results ever reported for these reactions. alpha-Bisabolol synthesized by this method contains no farnesol, which is a potentially allergenic compound and should be avoided in the commercially used alpha-bisabolol. This advantage is especially important because the distillative separation of alpha-bisabolol and farnesol is a troublesome task. The catalyst shows high turnover numbers and operates under mild nearly ambient conditions. (C) 2015 Elsevier B.V. All rights reserved.