STEREOCHEMICAL FEATURES OF BAKERS-YEAST MEDIATED TRANSFORMATION OF RACEMIC AND ENANTIOMERICALLY PURE 2-DEUTERO-3-CHLOROPROPIOPHENONE

Baker's yeast transforms (2R) and (2S) stereospecifically deuterated 3 -chloropropiophenone 11 and 12 into carbinols 14 and 15, and into prop iophenone samples retaining, at position 2, 71% and 84% deuterium, res pectively. Analogous experiments with randomly labelled ketone 10 gave rise to a mixture of the carbinols 15 and 14 and to propiopheilone, t hat retained 76% deuterium. The deuterium retention values in propioph enone generated from randomly and stereospecifically labelled substrat es 10, 11 and 12 indicate a non stereospecific elimination, accompanie d, however, by a minor pathway in which H(R) is preferentially removed .