Photoinduced α-Amino Alkylation of Heterocyclic Compounds via Catalytic Electron Donor–Acceptor Complexes

Visible light activation enables unprecedented synthetic transformations but typically requires precious metal complexes or elaborate organic dyes to absorb visible light and initiate reactivity. Herein, we report a more general, efficient, and economical catalytic platform for decarboxylative α-amino alkylation of heterocyclic compounds by a catalytic photoactive electron donor-acceptor (EDA) complex through n-π stacking and H-bonding, using readily available 1,4-diazabicyclo[2.2.2]octane (DABCO). Mechanistic studies and DFT calculations indicated that DABCO acts as a highly efficient dual-function catalyst, promoting both EDA complex formation and the intermolecular HAT process. This operationally simple, visible light-mediated platform is efficiently applied in the decarboxylative functionalization of primary, secondary, and tertiary α-amino acid esters with heterocyclic compounds, such as azauracil, coumarin, chromone, and quinoxalin-2(1<i>H</i>)-one, in good to excellent yields.