One-Pot Synthesis of Pyrrole-2-carboxylates and -carboxamides via an Electrocyclization/Oxidation Sequence

An electrocyclic ring closure is the key step of an efficient one-pot method for the synthesis of pyrrole-2-carboxylates and -carboxamides from chalcones and glycine esters or amides. The 3,4-dihydro-2H-pyrrole intermediates generated in situ are oxidized to the corresponding pyrroles by stoichiometric oxidants or by catalytic copper­(II) and air in moderate to high yields. A wide range of functional groups are tolerated, and further combination with an in situ bromination gives access to polyfunctional pyrrole scaffolds.