Ruthenium-catalyzed Heck coupling of 3-arylidene-oxindoles with alkenes: a facile synthesis of 3-allylidene-2(3 H )-oxindoles.

A simple and efficient Ru(II)-catalyzed olefination of 3-(arylbenzylidene)indolin-2-ones with alkenes is described. This is an atom and step-economical strategy with a wide substrate scope, good functional group tolerance, and suitability for gram scale synthesis. A plausible mechanism is also proposed for this synthetic transformation involving the formation of a 5-membered ruthenacycle and insertion of the alkene followed by β-hydride elimination to deliver the desired product.