Preparation of 61,62-, 61,63-, 61,64-, and 61,65-di-O-(α-d-glucopyranosyl) cyclomalto-octaoses

Four positional isomers of 61,6n-di-O-(d-glucopyranosyl)cyclomalto-octaoses (cG8s) (n = 2, 3, 4, and 5) were chemically synthesized by using the authentic compounds, 61,6n-di-O-trityl-cG8s or 61,6n-di-O-(tert-butyldimethylsilyl)-cG8s (n = 2−5) as the key glucosyl intermediates, and the glucosyl donor, 2,3,4,6-tetra-O-benzyl-α-d-glucopyranosyl trichloroacetimidate.