A novel and convenient method for the preparation of 5-(diphenylmethylene)-1H-pyrrol-2(5H)-ones; synthesis and mechanistic study

Abstract An efficient, regioselective synthesis has been developed for the preparation of 5-(diphenylmethylene)-1 H -pyrrol-2(5 H )-ones from readily available 1 H -pyrroles by sequential dibromination and selective organometallic bromine/lithium exchange followed by reaction with benzophenone. Comparison of various N -substituents was shown to demonstrate the high tolerance of the transformation to functional groups. The structures of the new products were determined by spectroscopic methods and confirmed by single-crystal X-ray diffraction measurement. In addition, theoretical study of the reaction mechanism and selective functionalization of the endocyclic double bond were also presented.