Chemoselective NIS/ cat. TfOH-mediated glycosylation of ethyl 2,3,4-tr
i-O-benzoyl-1-thio-beta-D-glucopyranoside (4) with ethyl -benzyl-1-thi
o-alpha/beta-D-erythro-apiofuranoside (3) gave dimer 5 in an excellent
yield. BF3Et2O-catalysed condensation of the alpha-trichloroacetimida
te 18, accessible in two steps from 5, with 3,4,5-trimethoxyphenol gav
e beta-linked derivative 19 which could be transformed in five steps i
nto the title compound. (C) 1998 Elsevier Science Ltd. All rights rese
rved.