Substrate-Induced Cooperative Ionic Catalysis: Difunctionalization of Indole Derivatives Employing Dimethyl Carbonate

Abstract

The global urge to adopt sustainable chemistry has resulted in the development of more environmentally benign strategies (EBS) that use CO₂ and CO₂-derived chemicals in a step-economic manner. In this context, we investigated a dual C–H methylation and (C═O)-methoxylation of indole derivatives using dimethyl carbonate (DMC) in the presence of catalytic amounts of Cs₂CO₃. Mechanistic insights include DMF-assisted, DMC-induced cooperative ionic catalysis, which allows DMC to act as both a nucleophilic and an electrophilic precursor, resulting in (C═O)-methoxylation and C–H methylation of N-benzylindolyl ketones.