Metal- and photosensitizer-free cross-dehydrogenative coupling through photoinduced energy transfer

Abstract

We developed a metal- and photosensitizer-free cross-dehydrogenative coupling (CDC) systems to promote the cleavage of strong C(sp3)-H bonds through a distinct non-photoredox engaged hydrogen atom transfer (HAT) process. Mechanistic experiments...

Merging Quinoxalin-2(1H)-ones Excitation with Cobaloxime Catalysis: C3 Alkylation of Quinoxalin-2(1H)-ones with Unactivated Alkyl Iodides and Carboxylic Acids under Light

“…For example, in 2021, the Li group found that various N -heterocycles could be successfully excited under >280 nm light irradiation and achieved the C­(sp 3 )–H bond heteroarylation by a hydrogen-atom transfer (HAT) process via a chlorine radical formed in situ . Recently, aliphatic C–H bonds also could be transferred into an alkyl radical intermediate in the presence of O 2 or TBHP . Herein, we propose excited quinoxalin-2­(1 H )-ones and combined cobaloxime catalysis to construct 3-alkylated products using carboxylic acids or alkyl iodides as alkylation regents without external strong acids, photocatalyst, or equivalent oxidants (Scheme C).…”