Ru-Catalyzed Chemoselective Olefin Migration Reaction of Cyclic Allylic Acetals to Enol Acetals.

A Ru-catalyzed olefin migration reaction of chiral cyclic allylic acetal is reported. The reaction generates cyclic enol acetal in a highly chemoselective manner. A variety of O,O- and N,O-acetals participated in the reaction with conservation of the stereochemical integrity of the acetal moiety. The utility of the reaction was demonstrated by the short and protective group-free syntheses of (L)-deoxyribonucleoside and β-amicetose glycoside.