ORGN 282

2'-Deoxy-2'-C-a-methylribonucleosides are potentially important as probes to study RNA structure and function and as therapeutic agents. The route for the synthesis of A, G, C and U 2'-deoxy-2'-C-a-methylribonucleosides from methyl 3,5-di-O-(p-chlorobenzyl)-a-D-ribofuranoside (1) is developed. Compound 1 was transformed into compound 2 via four steps in 48 % yield. 2'-Deoxy-2'-C-a-methyluridine and 2'-deoxy-2'-C-a-methyl-b-cytidine were then prepared from compound 2 in 72% yield (five steps) and 33% yield (eight steps), respectively. Compound 3 was obtained from compound 2 in 89% yield (two steps). 2'-Deoxy-2'-C-a-methyl-b-adenosine and 2'-deoxy-2'-C-a-methyl-b-guanosine were then prepared from compound 3 via four steps in 23% and 17% yield, respectively.