Biotransformation of the diterpene ribenone by Mucor plumbeus

The microbiological transformation of the diterpene ribenone (3-oxo-ent-13- epi-manoyl oxide) by the fungus Mucor plumbeus has been studied. Epoxidatio n of the vinyl group constitutes the main reaction and there exists a prefe rence for hydroxylation at C-1(alpha), C-6(alpha or beta) and C-12(beta) an d, to a lesser degree, at C-7(alpha) and C-11(beta). Other observed reactio ns were the reduction of the 3-oxo group to a 3 beta -alcohol and the forma tion of metabolites with a 1,2-double bond. In this work the stereochemistr y at C-14 of the diterpenes excoecarins A, B and C has been revised on the basis of X-ray data. (C) 2001 Elsevier Science Ltd. All rights reserved.