Biosynthesis of natural products. Part 1. Incorporations of ent-kaur-16-ene and ent-kaur-16-en-15-one into enmein and oridonin

Abstract

Incorporations of ent-kaur-16-ene (7a) and ent-kaur-16-en-15-one (14a) into enmein (1a) and oridonin (6a) by Isodon japonicus Hara have been demonstrated by tracer experiments with seven labelled ent-kaurene derivatives. Furthermore, evidence has been obtained that functionalisation of ent-kaur-16-ene at the allylic position C–15 proceeds through direct oxygenation.