Flavin and NAD (P) H coenzymes, from natural enzymatic redox systems, inspired the use of
flavin organocatalysts and a Hantzsch ester to perform transition-metal-free, aerobic
oxidations. Catechols and electron-rich phenols are achieved with as low as a 0.1 mol%
catalyst loading, 1 equiv of Hantzsch ester, and O2 or air as the stoichiometric oxidant
source.