Iterative C–H Amidation of Thiophenes under High-Valent Cp*Co(III) Catalysis

Iterative C-H functionalization assembles complex scaffolds efficiently, yet one-pot approaches are largely unexplored. Herein, we report iterative C-H amidation of thiophene derivatives using various dioxazolones under base-metal Cp*Co(III) catalysis in a single operation. Driven by cascade chelation assistance from the newly installed amide groups, this protocol proved to be effective in synthesizing complex molecules. Furthermore, detailed computational studies revealed that with an increase in the electron density on the thiophene ring, the C-H activation barrier subsequently decreases, accounting for the regioselectivity.