Substrate and Catalyst Effects in the Enantioselective Copper-Catalysed C–H Insertion Reactions of α-Diazo-β-oxo Sulfones

Excellent enantioselectivities of up to 98 % ee are achieved by employing the copper-bis(oxazoline)-NaBARF catalyst system in the C–H insertion reactions of α-diazo-β-oxo sulfones. The influence of variation of the bis(oxazoline) ligand, copper salt, additive and substrate on both the efficiency and the enantioselectivities of these intramolecular C–H insertion reactions has been explored. Optimum enantioselectivities are achieved with phenyl and diphenyl ligands across the substrate series.