(1-1)-linked C-disaccharides - Synthesis of bis(beta-D-galactopyranosyl)methane

Bis[C-(galactal-1-yl)]carbinol derivative 2, which is readily obtained by t ransformation of galactal into a vinyl carbanion and then reaction with a C -1-electrophile, was transformed into the title compound (Ib). The procedur e required first temporary protection of the carbinol hydroxy group and sub sequent transformation of the galactal moiety into the galactopyranosyl moi ety. Then deoxygenation of the carbinol and final deprotection could be car ried out.