Unnatural configuration nucleotide prodrug compounds

A compound of Formula I, II, III, IV, V or VI, or VII:

• or a stereoisomer or a pharmaceutically acceptable salt thereof,
• wherein:
• Y is H or —OR2;
• R1 and R2 are independently H, an optionally substituted C1-C10 alkyl, an optionally substituted C5-C10 aryl, an optionally substituted C1-C6 alkyl-C(O)—, an optionally substituted five to ten membered heteroaryl, or an optionally substituted —(CH2)x—(C5-C10 aryl);
• or alternatively, R1 and R2 may be taken together with the atoms to which they are attached and intervening atoms to form a four to ten membered heterocycle optionally substituted with between one and four C1-C6 alkyl groups,
• R3a and R3b are independently H or an optionally substituted C1-C10 alkyl;
• or
• alternatively, R3a and R3b may be taken together with the atom to which they are attached form a three to seven membered ring,
• R4 is halo, an optionally substituted C1-C10 alkyl, or an optionally substituted C1-C6 alkyloxy;
• R5a, R5b, R6a, and R6b are independently selected from the group consisting of H, ORA, halo, —CN, and an optionally substituted C1-C10 alkyl;
• RA is selected from the group consisting of H, an optionally substituted C1-C6 acyl, an optionally substituted C1-C6 alkyloxycarbonyl;
• and an optionally substituted C1-C6 carbamoyl;
• R7 is H or an optionally substituted C1-C10 alkyl;
• R8 is selected from the group consisting of an optionally substituted C1-C15 alkyl, an optionally substituted aryl, an optionally substituted benzyl, an optionally substituted phenylethyl, and an optionally substituted phenylpropyl.
• n is 0, 1, 2, or 3;
• x is 0, 1, or 2;
• and
• Base is a natural nucleoside base or a derivative or analog thereof.