Simple synthetic procedure for 2'- and 3'-tetrahydropyranyl ribonucleoside derivatives involving regioselective acylation with acyl chlorides, and synthesis of ribonucleotide oligomers.

Acylation of ribonucleosides through acyl chlorides in pyridine was induced with high regioselectivity under a controlled condition to give the corresponding 2',5'-diacylates in excellent yields and 2'-acylates, depending on the amount of the acyl chlorides used. On the other hand, a treatment of these resulting acylates on a silica gel (Wakogel C-300, Wako Pure Chemical Co. Ltd.) conducted their transformation into the corresponding 3',5'-diacylates or 3'-acylates effectively. These resulting 2',5'- and 3',5'-diacylates were further derived, by the known method, into the 3'- and 2'-O-tetrahydropyran-2-yl ribonucleoside derivatives, respectively, with which some ribonucleotide oligomer syntheses have been performed.