The biotransformation of manoyl oxide derivatives by Gibberella fujikuroi:: The fungal epimerization of an alcohol group

The microbiological transformations of jhanol (18-hydroxymanoyl oxide) and jhanidiol (1 beta,18-dihydroxymanoyl oxide) with the fungus Gibberella fujikuroi have been studied. In the biotransformation of the first compound there exists a preference for hydroxylation at C-1(a) and in lower yield at C-11(alpha or beta), while in that of the second, which possesses a 1 beta-hydroxylation, the main reaction observed is the oxidation of this 1 beta-hydroxyl to an oxo group. This product is then mainly reduced to the 1 alpha-alcohol or, in minor yield, hydroxylated at C-11(beta), C-6(beta) and C-2(alpha). The fungal epimerization of a hydroxyl group, as occurs in the biotransformation of the 1 beta-alcohol of jhanidiol to the la-alcohol, is a very rare process. (C) 1998 published by Elsevier Science Ltd. All rights reserved.