Abstract
Silicna gel-supported ceric ammonium nitrate (CAN-SiO <sub>2</sub> ) was found effective for rapid and selective cleavage of trityl (Tr), monomethoxytrityl (MMTr), and dimethoxytrityl (DMTr) groups from protected nucleosides and nucleotides under mild conditions. Efficiency of deprotections depended upon the stability of th resultant carbocationic species: DMTr <sup>+</sup> > MMTr <sup>+</sup> > Tr <sup>+</sup> . Use of a catalytic amount of this solid-supported reagent can also efficiently and selectively remove the tert butyldimethylsilyl or the triisopropylsilyl group from a primary hydroxyl functionality in di- or trisilyl ethers of ribonucleosides. A comparative stud of deprotection reactions by utilization of CAN alone or CAN-SiO <sub>2</sub> indicates a remarkable increase in the rate of the reactions involving a solid support. The mechanism of electron-transfer processes is proposed for the use of CAN-SiO <sub>2</sub> in the removal of these protective groups from organic molecules.