Synthesis of 3,4,5-trimethoxyphenyl 5-O-caffeoyl-β-D-erythro- apiofuranosyl-(1→6)-β D-glucopyranoside: Kelampayoside B

Article abstract of DOI:10.1016/S0040-4039(98)00673-X

Chemoselective NIS/cat. TfOH-mediated glycosylation of ethyl 2,3,4-tri- O-benzoyl-1-thio-β-D-glucopyranoside (4) with ethyl 2,3-di-O-acetyl-5-O- benzyl-1-thio-β-D-erythro-apiofuranoside (3) gave dimer 5 in an excellent yield. BF₃Et₂O-catalysed condensation of the α-trichloroacetimidate 18, accessible in two steps from 5, with 3,4,5-trimethoxyphenol gave β-linked derivative 19 which could be transformed in five steps into the title compound.