Micellar-Induced Selectivity and Rate Enhancement in the Acid-Catalyzed Cyclization and Rearrangement of Monoterpenes. The Solvolysis of Linalyl and Geranyl Acetates

Article abstract of DOI:10.1021/jo00266a007

The monoterpene linalyl acetate (1) undergoes acid-catalyzed solvolysis/cyclization at pH 3 in HCl/citrate buffer to yield three major acyclic alcohols, geranol (2), linalool (3), and nerol (4), and one cyclic alcohol, α-terpineol (5).The acyclic/cyclic alcohol ratio is 2.7 in no sodium dodecyl sulfate (SDS) controls after ca. 3 half-lives, compared to 8.5 when the reaction is carried out in a SDS micelle.No micellar rate effect was observed.The SDS-induced selectivity is explained in terms of the micelle-favoring acyclic conformers of linalyl acetate.In contrast to linalyl acetate, solvolysis of geranyl acetate (6) in the SDS micelle at pH 2 gives little product selectivity but yields a 7-fold rate effect relative to no SDS controls.This rate effect results in very different product distributions after 90percent completion of the reaction.The observed SDS rate effect for geranyl acetate is compatible with a difference in solvolysis mechanism for linalyl and geranyl acetate.