Process for the preparation of compounds useful as inhibitors of sglt2

A process for the preparation of compounds of formula (I)

• wherein Ring A and Ring B are one of the following:
• (1) Ring A is an optionally substituted unsaturated monocyclic heterocyclic ring, and Ring B is an optionally substituted unsaturated monocyclic heterocyclic ring, an optionally substituted unsaturated fused heterobicyclic ring, or an optionally substituted benzene ring;
• or
• (2) Ring A is an optionally substituted benzene ring, and Ring B is an optionally substituted unsaturated monocyclic heterocyclic ring, or an optionally substituted unsaturated fused heterobicyclic ring wherein Y is linked to the heterocyclic ring of the fused heterobicyclic ring;
• or
• (3) Ring A is an optionally substituted unsaturated fused heterobicyclic ring, wherein the sugar moiety X-(sugar) and the moiety —Y-(Ring B) are both on the same heterocyclic ring of the fused heterobicyclic ring, and Ring B is an optionally substituted unsaturated monocyclic heterocyclic ring, an optionally substituted unsaturated fused heterobicyclic ring, or an optionally substituted benzene ring;
• X is a carbon atom;
• Y is —(CH2)n—;
• wherein n is 1 or 2;
• provided that in Ring A, X is part of an unsaturated bond;
• or a pharmaceutically acceptable salt or solvate thereof;
• comprising
• reacting a compound of formula (V) wherein LG1 is a leaving group, with a mixture of a zinc salt and an organo-lithium reagent;
• in a first hydrocarbon solvent;
• at a temperature in the range of from about −78° C. to about room temperature;
• to yield a mixture of the corresponding compound of formula (VI), wherein M1 is lithium, and the zinc salt;
• admixing to the mixture of the compound of formula (VI) and the zinc salt a first ether solvent;
• to yield the corresponding compound of formula (VII), wherein M2 is a reactive zinc species;
• reacting the compound of formula (VII), with a compound of formula (VIII), wherein each Z is an independently selected oxygen protecting group and wherein LG2 is a leaving group;
• to yield the corresponding compound of formula (IX);
• de-protecting the compound of formula (IX);
• to yield the corresponding compound of formula (I).