Methods for the preparation of ribosides

A method of preparing a compound of Formula VIII:

• the method comprising:
• forming a reaction mixture with MgCl2, diisopropylethylamine, a compound of Formula IX:
• and a compound of Formula (X):
• to form the compound of Formula wherein
• each Ra is PG;
• each PG group is a hydroxy protecting group, or both PG groups are combined to form −C(R19)2−;
• Rei and Rei are each independently H, C1-C6 alkyl or benzyl;
• Rf is H, C1-C8 alkyl, benzyl, C3-C6 cycloalkyl, or ‘CH2-C3-C6 cycloalkyl;
• R19 is H, C1-C8 alkyl, phenyl or substituted phenyl;
• and
• LG is 4-nitrophenoxy or pentafluorophenoxy.

A method of preparing a compound of Formula (VIII):

• the method comprising:
• forming a reaction mixture with MgCl2, diisopropylethylamine, a compound of Formula (IX-a:)
• and a coumpound of Foruma (X):
• to form the compound of Formula (VIII),
• wherein
• Ra is a hydroxy protecting group;
• each R35 is independently a hydroxy protecting group, or both R35 groups are combined to form −C(R19)2−;
• Re1 and Re2 are each independently H, Ci-C6 alkyl or benzyl;
• Rf is H, C1-C8 alkyl, benzyl, C3-C6 cycloalkyl, or -CH2-C3-C6 cycloalkyl;
• R19 is H, C1-C8 alkyl, phenyl or substituted phenyl;
• and
• LG is 4-nitrophenoxy or pentafluorophenoxy.