Synthesis and elucidation of absolute stereochemistry of salaprinol, another thiosugar sulfonium sulfate from the ayurvedic traditional medicine Salacia prinoides

Abstract Synthesis and elucidation of absolute stereochemistry of salaprinol ( 3 ) isolated from the root and stems of Salacia prinoides , which has been used for the treatment of diabetes in India, Sri Lanka, and Southeast Asia countries, is described. Compound 3 and its 2′-epimer, epi -salaprinol ( epi -3 ) were synthesized via the coupling reaction of a cyclic sulfate, 2- O -benzylglycerol 1,3-cyclic sulfate ( 5 ), with a thiosugar, 1,4-dideoxy-1,4-epithio- d -arabinitol ( 6 ), as the key reaction, and S configuration of the asymmetric center in the side chain of 3 was elucidated by the X-ray crystallographic analysis.