A New Synthesis of Pyrroles from Benzimidazolium N-Cyanomethyl Ylides and Alkyne DipolarophilesM.R.C. thanks the University of Cape Town and the NRF (Pretoria) for financial support.
Received: 28 April 2017
Accepted after revision: 06 June 2017
19 July 2017 (eFirst)
A straightforward synthesis of highly functionalized pyrroles was achieved by a one-pot reaction between 3-(cyanomethyl)benzimidazolium salts and acetylenic dipolarophiles under reflux in 1,2-epoxybutane. The new pyrroles can also be obtained by a one-pot three-component reaction from substituted benzimidazoles, bromoacetonitrile, and activated acetylenes. The structures of the pyrroles were deduced by NMR spectroscopy and confirmed by X-ray crystal analysis.