Copper-catalyzed direct coupling of benzoxazin-2-ones with indoles for the synthesis of diverse 3-indolylbenzoxazin-2-ones: access to natural cephalandole A

Abstract

Diverse and functionalized 3-indolyl benzo[b][1,4]oxazin-2-ones were synthesized via copper-catalyzed direct coupling of benzo[b][1,4]oxazin-2-one and indoles in air.

Visible-light-induced C(sp3)–H activation for a C–C bond forming reaction of 3,4-dihydroquinoxalin-2(1H)-one with nucleophiles using oxygen with a photoredox catalyst or under catalyst-free conditions

“… 9 Alternatively, a copper-catalyzed direct coupling of benzoxazin-2-ones with indoles was reported by Lee and coworkers. 10 Nevertheless, despite these advances, an efficient, green, and convenient protocol for the synthesis of these systems remains a topic of high interest in chemical research. 11 …”

3d Transition Metals for C–H Activation

“…Subsequent studies by other researchers revealed cross-coupling of two heteroarenes or heteroarenes with polyfluoroarenes in related copper-based manifold (Scheme ). − …”

Metal‐Catalyzed Oxidative C−H Bond Functionalization of 1,4‐Benzoxazinones

“…[14] In 2017, Lee and co-workers have developed Cu-catalyzed oxidative CÀ H bond functionalization reaction of 1,4-benzoxazinone. [15] They reported a Cu-catalyzed direct crossdehydrogenative coupling reaction between benzoxazin-2-ones (1 j) and indoles (2 j). Initially, they tried reaction between benzoxazin-2-one and N-methylindole in the presence of 10 mol% CoCl 2 as catalyst in dichloroethane solvent at 60 °C under air for 24 hours, which gave only 32 % yield of the desired product (3 j).…”

“…In 2017, Lee and co‐workers have developed Cu‐catalyzed oxidative C−H bond functionalization reaction of 1,4‐benzoxazinone [15] . They reported a Cu‐catalyzed direct cross‐dehydrogenative coupling reaction between benzoxazin‐2‐ones ( 1 j ) and indoles ( 2 j ).…”