Abstract
A simple, convenient, and efficient oxidative cross-coupling reaction of oxindoles with ketones toward a variety of 3-(2-oxoalkyl)-3-hydroxyoxindoles in moderate to excellent yields has been developed. This transformation proceeds via a tandem oxidative cross-coupling by using 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) in air as an environmentally benign oxidant. This methodology provides an alternative approach for the direct generation of all-carbon quaternary centers at the C3 position of oxindoles.