Patent ID: 8193339

Claim:
A process of preparing a protected β-nucleoside compound formula (I): wherein R 1 is alkyl, aralkyl, trityl, alkyldiarylsilyl, trialkylsilyl, triarylsilyl, alkylcarbonyl, or arylcarbonyl; R 2 is RC(O)—, RR′NC(O)—, ROC(O)—, RC(S)—, RR′NC(S)—, or ROC(S)—; each of R and R′, independently, being H, alkyl, aryl, cycloalkyl, heterocycloalkyl, or heteroaryl; each of R 3 and R 4 is fluoro; and B is in which R 5 is H, alkyl, or aryl; R 6 is H, alkyl, alkenyl, halo, or aryl; X is N or C—R″, R″ being H, alkyl, alkenyl, halo, or aryl; and Y is an amino protecting group; the process comprising reacting, in the presence of a transition metal salt, a tetrahydrofuran compound of formula (II): wherein R 1 , R 2 , R 3 , and R 4 are as defined above and L is fluoro, chloro, bromo, or iodo, with a nucleobase derivative of the following formula: wherein R 5 , R 6 , and Y are as defined above and Z is a hydroxyl protecting group; and wherein the transition metal salt is a silver salt.