Patent ID: 8481713

Claim:
A method for the preparation of a 2′-deoxy-2′-fluoro-2′-C-methyl-β-D-ribofuranosyl nucleoside of the following formula: wherein the base is: wherein R 2 and R 4 are independently H, OH, NH 2 , or OR′; R′ is an optionally substituted straight, branched, or cyclic alkyl of C 1 -C 12 ; Y is N or CH; the method comprising the following steps: (a) reacting a nucleoside intermediate of the following formula: wherein the protected base is the base protected by a protecting group, wherein the protecting group is benzoyl; wherein R 3 and R 5 are each independently tetrahydropyranyl, methyl, ethyl, benzyl, p-methoxybenzyl, benzyloxymethyl, phenoxymethyl, methoxymethyl, ethoxymethyl, mesyl, tosyl, trifluoroacetyl, or trichloroacetyl, with diethylaminosulfur trifluoride or bis(2-methoxyethyl)aminosulfur trifluoride to yield a fluorinated intermediate of the following formula: (b) deprotecting the R 3 and R 5 groups of the product of step (a) by treatment with a boron trihalide to yield an intermediate of the following formula: (c) saponifying the product of step (b) to yield the desired nucleoside.