Regioselective C-3-alkylation of quinoxalin-2(1)-ones C-N bond cleavage of amine derived Katritzky salts enabled by continuous-flow photoredox catalysis.

An efficient, transition metal-free visible-light-driven continuous-flow C-3-alkylation of quinoxalin-2(1)-ones has been demonstrated by employing Katritzky salts as alkylating agents in the presence of eosin-y as a photoredox catalyst and DIPEA as a base at room temperature. The present protocol was accomplished by utilizing abundant and inexpensive alkyl amine (both primary and secondary alkyl) and as well as this a few amino acid feedstocks were converted into their corresponding redox-active pyridinium salts and subsequently into alkyl radicals. A wide variety of C-3-alkylated quinoxalin-2(1)-ones were synthesized in moderate to high yields.