"On-water," microwave-assisted, Pd-catalyzed synthesis of indoles from imines and o-difunctionalized arenes.

Regioselectively substituted indoles are prepared by a Pd-catalyzed C-C/C-N bond-forming sequence from imines and o-dihaloarenes or o-haloarene sulfonates. The heterogeneous reaction as a suspension in water and under microwave heating offers important advantages in comparison with the conventional reaction in an organic solvent, among them, operational simplicity, the employment of KOH solutions instead of alkoxides, and a dramatic reduction of reaction times.