Efficient synthesis of kinsenoside and goodyeroside a by a chemo-enzymatic approach.

Kinsenoside (1) and goodyeroside A (2), two naturally occurring stereoisomers with diverse biological activities, have been synthesized efficiently by a chemo-enzymatic approach with a total yield of 12.7%. The aglycones, (R)- and (S)-3-hydroxy-γ-butyrolactone, were prepared from D- and L-malic acid by a four-step chemical approach with a yield of 75%, respectively. These butyrolactones were then successfully glycosidated using β-D-glucosidase as a catalyst in a homogeneous organic-water system. Under the optimized enzymatic conditions, the yields of kinsenoside and goodyeroside A in the enzymatic steps both reached 16.8%.