A Study on the Lipase-catalysed Acylation of 6,7-Dihydroxy-linalool

We here describe a study of the enzyme-mediated acylation reaction of 6,7-dihydroxy-linalool stereoisomers, which are natural triols occurring in different vegetal species. We found that only few lipases are able to catalyze the acylation of the secondary hydroxy group present in these isomers and only lipase from Candida rugosa and novozyme 435 provide either (3R,6R)-6-acetoxy-7-hydroxylinalool or (3R,65)-6-acetoxy-7-hydroxylinalool in moderate and very good isomeric purity, respectively. Even for these favorable cases the reaction proceeds very sluggishly. Our finding can give a sensible interpretation to the fact that 6-acyl-7-hydroxy-linalool derivatives do not occur in nature, whereas the corresponding glycosides, whose formation is catalyzed by glycosidase, are very common.