Synthesis of a New Class of C2-Symmetrical Biheteroaryls by Ammonium Cerium(IV) Nitrate Mediated Dimerization of 2-(Furan-3-yl)pyrroles.

Polyfunctionalized 2-(furan-2-yl)pyrroles and 2-(furan-3-yl)-pyrroles derived from 2-azetidinone-tethered allenes by two independent cerium(IV)-mediated single-electron oxidations provided a (4-oxopent-2-enoyl)pyrrole and 3,3'-bis(pyrrol-2-yl)-2,2'-bifurans, respectively. Access to the oxidation precursors was achieved by regiocontrolled cyclization of β-al-lenamine intermediates derived from selective β-lactam nucleus breakage of 2-azetidinone-tethered allenols.