methyl 2-O-benzyl-4,6-O-benzylidene-3-O-[2-O-benzyl-4,6-O-benzylidene-3-O-(2-O-benzyl-4,6-O-benzylidene-3-O-(methylsulfonyl)ethoxymethyl-α-D-mannopyranosyl)-β-D-mannopyranosyl]-α-D-mannopyranoside