NATURAL ABUNDANCE H-2 NUCLEAR-MAGNETIC-RESONANCE STUDY OF THE ORIGIN OF (R)-DELTA-DECANOLIDE

The site-specific natural abundance deuterium distribution of (R)-delta-decanolide obtained through a variety of synthetic methods has been determined by H-2 NMR spectroscopy. This technique provided a means of distinguishing between ''natural'' delta-decanolide biogenerated from delta-2-decenolide isolated from Cryptocaria massoia (Massoi lactone) with bakers' yeast and other delta-decanolides obtained in different ''non-natural'' ways. A mechanistic interpretation has been proposed to explain the difference of site-specific deuterium content between the delta-decanolides obtained by reduction of Massoi lactone with bakers' yeast or by catalytic hydrogenation.