Synthesis of Highly Substituted 2-Arylindoles via Copper-Catalyzed Coupling of Isocyanides and Arylboronic Acids

Organic Letters 20(11), 3263-3267, DOI: 10.1021/acs.orglett.8b01132

Highly functionalized 2-arylindoles were synthesized from 2-alkenylarylisocyanides and arylboronic acids using a simple, inexpensive copper catalyst. The reaction exhibits excellent functional group tolerance for both the arylisocyanide and boronic acid coupling partners. To avoid the direct handling of the pungent arylisocyanide starting materials, continuous flow chemistry is further demonstrated to provide safe and effective access to 2-arylindoles through in situ dehydration and cyclization of easy-to-handle 2-alkenyl-N-formylanilines.