Hydrogen-Bond-Catalyzed Arylation of 3-(Aminoalkyl)indoles via C–N Bond Cleavage with Thiourea under Microwave Irradiation: An Approach to 3-(α,α-Diarylmethyl)indoles
of 3-(aminoalkyl)indoles with aryl alcohols and other aromatic nucleophiles through C–N bond cleavage under microwave irradiation to synthesize 3-(α,α-diarylmethyl)indoles. The method uses thiourea as catalyst, which is environmentally benign, water-tolerant and easy to handle. Notably, acid-sensitive substrates are tolerated under the reaction conditions. Thiourea activates the tertiary amine through
Jnsymmetrical arylbis(3-indolyl)methanes have been synthesized via a Bronsted acid catalyzed Friedel-Crafts alkylation of α-(3-indolyl)benzylamines with N-methylindole. With 5 mol% of the catalyst, the reaction proceeds smoothly under mild conditions, affording the unsymmetrical triarylmethanes in excellent yields (up to 98%).