STEREOCHEMISTRY OF THE METHYNE-METHYLENE CONVERSION IN THE BIOGENERATION OF (S)-DELTA-DECANOLIDE AND (S)-GAMMA-DODECANOLIDE FROM (13RS)-13-HYDROXYOCTADECA-9Z,11E-DIENOIC AND (10RS)-10-HYDROXYOCTADEC-8E-ENOIC ACID

In Cladosporium suaveolens the bioconversion of (13RS)-13-hydroxy-[9,10,11,12-H-2(4)]octadeca-9Z,11E-dienoic acid into axially, 2,3,4-trideuteriated (S)-delta-decanolide indicate that protonation of the dienic system occurring at some stage of the degradative sequence takes place on the same face of the molecule. The protonation at position 9 of (10RS)-10-hydroxy-[9,10-H-2(2)]octadeca-8E-enoic acid occurring in Yarrowia lipolytica during the biogeneration of (S)-gamma-dodecanolide shows the same steric course.