Mechanism of the inverse-electron demand Diels-Alder reaction of 2-aminopyrroles with 1,3,5-triazines:detection of an intermediate and effect of added base and acid

摘要

In base,a 2-aminopyrrole reacted with a 1,3,5-triazine to give a zwitterion (Meisenheimer complex).Acid promoted its conversion to the pyrrolo[2,3-d]pyrimidine.A cascade mechanism with reversible steps is proposed to explain why both a base and an acid are needed for the cycloaddition to occur.