抄録
The stereochemistry of microbial transformation of (-)-α-santonin (1) by Streptomyces cinereocrocatus is described. Fermentation of (-)-α-santonin (1) with S. cinereocrocatus led to the formation of (+)-1, 2-dihydro-α-santonin (2). To elucidate the stereochemistry of the microbial hydrogenation of (-)-α-santonin, (-)-[1, 2-2H]-α-santonin (1a) was synthesized from 1, and subjected to the microbial transformation. Analysis of the 400 MHz proton nuclear magnetic resonance spectrum of the deuterated product clearly revealed that the microbial hydrogenation of 1a proceeds stereo-specifically with trans-addition of hydrogens via si face attacks at the 1 and 2 positions.
