Enantioselective Intramolecular Copper Catalyzed C-H insertion of α-Diazosulfones

Maguire et al. have reported an enantioselective intramolecular chiral copper bis-oxazoline catalyzed C-H insertion of α-diazosulfones. On treatment of the alpha-diazosulfones with CuCl, the chiral bis-oxazoline ligand and sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBARF) in refluxing dichloromethane, the corresponding cis-thiopyranes were isolated in high enantioselectivities.