An Efficient Method for the Synthesis of β-D-Ribonucleosides Catalyzed by Metal Iodides.

Abstract Several β-d-ribonucleosides were synthesized in high yields under mild conditions by N-glycosylations of methyl 2,3,5-tri-O-benzoyl-β-d-ribofuranosyl carbonate (1) with trimethylsilylated nucleoside bases in acetonitrile using a catalytic amount of metal iodide such as SnI2, SbI3 or TeI4. A deprotection of N6 -benzoyl group of coupling product took place to a considerable extent when N6 -benzoyl-N6 , N9 -bis(trimethylsilyl)adenine was employed as a nucleoside base using SnI2 or SnCI2 as a catalyst while it was minimized when SbI3 or TeI4 was used. Further, the N-glycosylation of 1 with 7-trimethylsilyltheophylline in the presence of a catalytic amount of metal iodide was more effectively achieved in nitrile solvents other than acetonitrile. #This paper is dedicated to Dr. Yoshihisa Mizuno on the occasion of his 75th birthday.