Process for the production of branched nuclesidos 2

Process for the preparation of a compound of 2-C-methyl-D-ribofuranose optionally protected, comprising: (a) reacting D-fructose with CaO in water to obtain a 2-C-methyl-D-ribonic-γ lactone; (B) optionally protecting the 2-C-5 methyl-D-ribonic γ-lactone with a protecting group to form 2,3,5 (protected independently and Optionally) -2-C-methyl- D-ribonic γ-lactone; (C) reacting the 2,3,5 (protected independently and Optionally) -2-C-methyl-D-ribonic-γ- lactone with a reducing agent selected from the group consisting of Red-Al, NaHTe, SmI2, H2 and a Pd catalyst phosphine, and LiAl (OtBu) 3H to reduce the lactone to a hydroxyl group and form a compound of 2,3,5- (protected independently and Optionally) - 2-C-methyl-D-ribofuranose; and (d) optionally protecting the compound of 2,3,5- (protected independently and Optionally) -2-D-ribofuranose Cmetil- with a protecting group to form the 1,2,3,5- (protected independently and Optionally) -2-C-methyl-β-D-ribofuranose.