Feedback Inhibition in Chemical Catalysis Leads the Dynamic Kinetic to Kinetic Resolution in C3-Indolylation of Spiro-epoxyoxindoles.

The first feedback inhibition, similar to enzyme catalysis, in the Co(III)salen-catalyzed asymmetric ring-opening reaction of N-free spiro-epoxyoxyindole has been discovered, which leads dynamic kinetic to kinetic resolution. This is the first report of the enantioselective construction of all carbon quaternary center from any epoxide employing metal-salen catalyst until date. This protocol provides an easy access of 3-(3- indolyl)oxindole methanols, a privileged building block for the synthesis of a large variety of 3,3'-bisindole alkaloids.