Direct C–H Cyanoalkylation of Quinoxalin-2(1H)-ones via Radical C–C Bond Cleavage

Abstract

An efficient synthesis of cyanoalkylated heteroarenes via iron-catalyzed direct C-H cyanoalkylation of heteroarenes has been developed. Structurally diverse cyanoalkyl motifs generated through C-C bond cleavage of cyclobutanone oxime esters have been introduced into quinoxalin-2(1H)-ones, flavone, benzothiazoles, and caffeine in good to excellent yields. Remarkably, less-strained cyclopentanone and unstrained cyclohexanone oxime esters were also amenable substrates in this cyanoalkylation reaction.

Photoredox Catalyst Free, Visible Light‐Promoted C3−H Acylation of Quinoxalin‐2(1H)‐ones in Water

“…[4] In the past several years, the direct C3À H functionalization of quinoxalin-2(1H)-ones provided a very efficient and straightforward route to access 3substituted quinoxalin-2-one derivatives. [5] Successful examples including alkylation, [6] arylation, [7] alkoxylation, [8] amination [9] phosphonation [10] and others [11] were sequentially conducted to prove the approach attractive and valuable. Comparing with those well-developed processes, C3À H acylation of quinoxalin-2(1H)-ones are relatively less investigated.…”

Transition‐Metal‐Free Radical C−H Methylation of Quinoxalinones with TBHP

“…In particular, more attention was paid to the synthesis of C3‐functionalized quinoxalin‐2(1H)‐one analogues, such as alkylation, arylation, acylation, amination, and phosphonation . Especially, the direct hydroxyalkylation, benzylation, oxyalkylation and cyanoalkylation of quinoxalin‐2(1H)‐ones synthesis of 3‐alkylquinoxalin‐2(1H)‐ones has been reported (Scheme , a–). However, to the best of our knowledge, the synthesis of quinoxalin‐2(1H)‐ones bearing a methly substituent at the C3 position via direct C–H bond functionalization has not been reported.…”

Photoinduced Nitrile Formation from O‐(Arylcarbonyl) oxime: Usage as a Photoremovable Protecting Group

“…The nitrile group was released from this ACO molecule via a unimolecular sensitization pathway, thereby demonstrating its potential applicability as a PPG for nitrile groups. Recent reports show elegant photochemical formations of the nitrile compounds from cyclobutanone oxime derivatives by means of a ring‐opening reaction . However, in these studies, the applicable substrates are rather limited.…”