Consecutive catalytic hydroformylation-acetalization of unsaturated carbohydrates (glucals) to give the dimethyl acetal of 2-C-formyl-D-alditol derivatives using the catalytic system [Rh(µ-OMe)(cod)]2/P(O-o-ButC6H4)3/PPTS is strongly dependent on the protecting groups on the carbohydrate.
