“…Thus, as for cinnamaldehyde (E)-14, the addition to C  -re face of a D − from the cofactor (which has exchanged the hydrogen to be delivered in the reduction with deuterated water [19]) and of a D + to C ␣ -re face from the solvent gave the deuterated saturated aldehyde shown in Scheme 5a, which was then reduced by one of the alcohol dehydrogenases active in fermenting BY to afford compound 21. The absolute configuration of the stereogenic centres C 2 and C 3 in compound 21 was thus assigned to be (2S,3S), while that of C 1 was established to be R on the basis of the known mode of BY reduction of the carbonyl group of cinnamaldehyde [20,21]. The sample contained also 23% of the diastereoisomer (1R,2R,3S)-21, due to the lower stereoselectivity of the bioreduction when the substrate was added in ethanol solution.…”