1,3-dipolar cycloaddition reactions of benzimidazolium-ylides to an activated symmetric alkyne

Abstract

The cycloaddition reactions represent an important way to obtain cyclic structures and take place between two or more reactants containing double or triple bonds in the molecule. After Huisgen, the addition of 1,3-dipole to a dipolarophile, takes place through a concerted mechanism, when two  bonds are formed. [1,2] The purpose of this research is to study the Huisgen [3+2] dipolar cycloaddition reactions carried out in a conventional way (stirring at room temperature) and non-conventional way (ultrasonic irradiation), between benzimidazolium-ylides and an activated symmetric substituted alkyne - dimethyl acetylenedicarboxylate (DMAD) - as dipolarophile. [3-5] The Huisgen 3+2 dipolar cycloaddition reaction of benzimidazolium ylides to dymethyl acetylenedicarboxilate (DMAD) afford generating of three types of hybrid quinoline-benzimidazole cycloadducts and, according with the source of energy and solvent used the reactions pathway could be conducted selective.