Synthesis of N-protected deoxynucleosides via 3',5'-cyclic silyl derivatives

Treatment of deoxynucleosides with dichlorosilanes in pyridine gives 3',5'-cyclic silyl derivatives. Dimethylsilanediyl derivatives and tetramethyldisiloxanediyl derivatives are not stable solvolytically and cleavage of these silyl ethers to the parent deoxynucleosides occurs readily on addition of water. These solvolytically labile bifunctional silyl groups serve as simultaneous transient protecting 3'- and 5'-hydroxyl functions. Acylation and successive hydrolysis of 3',5'-cyclic silyl derivatives gives the corresponding N-protected deoxynucleosides. Some N-acylated deoxy-adenosines and N-anisoyldeoxycytidine were synthesized easily by this N-protection method.