Ligand‐Controlled Stereoselective Synthesis of 2‐Deoxy‐β‐C‐glycosides by Cobalt Catalysis

2‐Deoxy‐β‐C‐glycosides represent an important class of carbohydrates that are present in many bioactive molecules. However, owing to the lack of substituents at the C2 position, the stereoselective synthesis of 2‐deoxy‐β‐C‐glycosides is highly challenging. Herein, we report a ligand‐controlled stereoselective C‐alkyl glycosylation reaction to access 2‐deoxy‐β‐C‐alkyl glycosides from readily available glycals and alkyl halides. This method exhibits broad substrate scope and excellent diastereoselectivity under very mild conditions. In addition, unprecedented stereodivergent synthesis of 2‐deoxy‐C‐ribofuranosides is achieved using different chiral bisoxazoline ligands. Mechanistic studies suggest that hydrometallation of the glycal with the bisoxazoline‐ligated Co−H species may be the turnover‐limiting and stereodetermining step of this transformation. A ligand‐controlled cobalt‐catalyzed hydroalkylation of glycals was developed to access 2‐deoxy‐β‐C‐alkyl glycosides. This method exhibits broad substrate scope and excellent diastereoselectivity under very mild conditions. In addition, unprecedented stereodivergent synthesis of 2‐deoxy‐C‐ribofuranosides was achieved using different chiral bisoxazoline ligands.