Determination of the absolute configuration of (-)-(3R)-O-beta-D-glucopyranosyloxy-5-phenylpentanoic acid from Polygonum salicifolium

The absolute configuration of the title compound has been determined after its enzymatic hydrolysis to 3-hydroxy-5-phenylpentanoic acid, esterification, and identification of the enantiomerically pure methyl (3R)-hydroxy-5-phenylpentanoate by HPLC on Chiralcel(R)OD-H. For reasons of inconsistent literature data, enantioselective reductions of methyl 3-oxo-5-phenylpentanoate have been reinspected and the stereochemical outcome unequivocally confirmed by both chiroptical and HPLC retention data.