The O′-pivaloyl diesters of N′-acetyl-azanucleosides were obtained from N-[1, 3-di (pivaloyloxy) prop-2-yl]-N-(pivaloyloxymethyl) acetamide and a silylated nucleobase under Vorbrüggen's conditions. Unexpectedly, de-pivaloylation of the diesters under basic conditions afforded the corresponding nucleobase and N-acetylserinol. Mechanistic investigations showed that these products result from the following cascade of ...