Rhodium-Catalyzed Additive-Free C-H Ethoxycarbonylation of (Hetero)Arenes with Diethyl Dicarbonate as a CO Surrogate

A rhodium-catalyzed C(sp(2))-H ethoxycarbonylation of indoles and arylpyridines using diethyl dicarbonate was developed. The catalytic process features an additive-free ethoxycarbonylation reaction, in which only ethanol and CO2 are produced as byproducts, providing a CO-free and operationally simple protocol. The introduced ethoxycarbonyl group is easily transformed into other ester and amide functionalities in a single step. Moreover, the reaction can be successfully applied on gram scale, and allows for the efficient synthesis of indole-2-carboxylic acid esters and isophthalates.

Automated summary

The rhodium-catalyzed C(sp(2))-H ethoxycarbonylation reaction of indoles and arylpyridines using diethyl dicarbonate was developed. This catalytic process features an additive-free reaction with only ethanol and CO2 produced as byproducts, providing a CO-free and operationally simple protocol. The introduced ethoxycarbonyl group can be easily transformed into other ester and amide functionalities in a single step.