Cascade Oxidative Coupling/Cyclization: A Gateway to 3-Amino Polysubstituted Five-Membered Heterocycles

Taking advantage of the coordinating activation strategy, we have developed the cascade oxidative coupling/cyclization of alpha-C(sp(3))-H bonds of amines with enamines or beta-keto esters for the synthesis of three types of five-membered heterocycles. alpha-Amino acids as the substrate lead to 3-amino 1,3-dihydro-2H-pyrrol-2-ones and furan-2(3H)-ones by using air or dioxygen as the sole clean oxidant, respectively. alpha-Amino ketones give a range of 3-amino 1H-pyrroles by using di-test-butyl peroxide as the oxidant. A three-component, one-pot reaction from readily available amine, beta-keto ester, and alpha-amino ketone enhances the practicality of the modular construction of 1H-pyrrole scaffolds. This programmed protocol features simple reaction conditions, readily available starting materials, broad substrate scope, and high functional group tolerance.