Direct Alkylation of Quinoxalinones with Boracene-Based Alkylborate under Visible Light Irradiation.

An efficient synthesis of a variety of 3-alkyl quinoxalinones via C-H direct alkylation by photoredox catalysis between quinoxalinones and alkylborates is reported. A range of quinoxalinones was tolerated well. This visible-light photocatalysis reaction allows access to structurally diverse 3-alkyl quinoxalinones in good to excellent yields. The practicality of this protocol was demonstrated by the concise synthesis of a potential bioactive nonpeptide angiotensin II receptor antagonist.