A study of the microbiological reduction of α,β-unsaturated carbonyl ent-kaurenes by Gibberella fujikuroi

The incubation of 18-hydroxy-15-oxo-ent-kaur-16-ene with the fungus Gibberella fujikuroi gave 16α,17-dihydro-15-oxo derivatives, whilst the feeding of 3-oxo-15α,16α-epoxy-ent-kaur-1-ene afforded a series of products, which conserve the 1,2-double bond. These results indicated that the hydrogenation of α,β-unsaturated carbonyl compounds with an ent-kaurene skeleton by this fungus is a stereospecific and regiospecific reduction, that does not depend on the biosynthetic route of gibberellins and kaurenolides.