?-D-galactosidase-catalysed synthesis of partially protected ?-linked digalactopyranosides

The facile synthesis of partially protected α-linked digalactopyranosides was achieved employing α-D-galactosidase as stereospecific catalyst and partially protected α-galactopyranosides as acceptors. The influence of changing the structure and the number of protecting groups on yield and regioselectivity is described. The preparative synthesis of the structure Galp α1-3 (2-O−Bn) Galp α-OMe, which is useful e.g. for the preparation of blood group determinant B and analogs, was achieved.