Regioselective [1N+2C+2C] Assembly of Fully Decorated Pyrroles from Primary Amines, 1,2-Diaza-1,3-dienes, and 2,3-­Allenoates

A mild, sequential multicomponent reaction strategy for the regioselective synthesis of functionalized pentasubstituted pyrroles from readily accessible primary amines, 1,2‐diaza‐1,3‐dienes, and 2,3‐allenoates, has been developed. The process allows a [1N+2C+2C] annulation to be achieved through two sequential hydroamination reactions followed by an enamine‐carbocyclization. Moreover, allenoates, as synthetic equivalents of monoactived alkynes, permit the specific preparation of multifunctionalized pyrroles. A sequential multicomponent reaction with three different substrates reacting in a well‐defined manner to form fully substituted pyrroles has been developed. The process involves a primary amine, which enables two sequential nucleophilic additions and promotes, via enamino carbocyclization, the pyrrole ring formation. Regioselective preparation of the multifunctionalized pyrroles was thus achieved.