Oxidative rearrangement of indoles mediated by 2-bromoethanol and hydrogen peroxide to access spirooxindoles

Abstract

Oxidative rearrangement of indoles into a series of spirooxindoles has been accomplished by using an exclusive reagent system containing 2-bromoethanol and hydrogen peroxide. This alternative metal-free approach features utilization of HOBr, generated in situ from the reaction of 2-bromoethanol and hydrogen peroxide via a radical pathway, as an electrophilic species to enable the spirolization to occur.