3,3′-Oxybis(dimethoxytrityl chloride) (O-DMTCl): synthesis and applications of a novel bifunctional protecting group

3,3′- xybis( i ethoxy rityl chloride) (O-DMTCl) was synthesized as a novel, acid-labile bifunctional protecting reagent. The reactions of O-DMTCl with base-protected ribonucleosides afforded unexpectedly 2′,5′-cyclic protected ribonucleosides in addition to the expected 3′,5′-cyclic protected ribonucleosides in good yields.