Ytterbium(iii) perchlorate as a catalyticpromoter of the glycosylation of l-o-methoxyacetylsugars with alcohols. In preparation {4,10-Bis[2-(2-oxidobenzyl-idene-amino-[kappa]2N,O)benz-yl]-1,7-dioxa-4,10-diaza-cyclo-dodecane-[kappa]4O1,N4,O3,N10}ytterbium(III) perchlorate which is a acetonitrile solvate.