The title compd. as its Me glycoside was efficiently synthesized using a block synthesis approach. Halide-assisted glycosylation between 6-O-acetyl-2,3,4-tri-O-benzyl-a-D-glucopyranosyl iodide and Et 2-O-acetyl-4,6-di-O-benzyl-1-thio-a-D-mannopyranoside using triphenylphosphine oxide as promoter yielded, with complete a-selectivity, a disaccharide building block in high yield. The per-benzylated deriv. of this proved to be an excellent donor affording 88% of the protected target tetrasaccharide in an NIS/AgOTf-promoted coupling to a known Me dimannoside acceptor. Deprotection through catalytic hydrogenolysis then gave the target compd. in 47% overall yield. [on SciFinder (R)]