Visible‐Light‐Driven Multicomponent Radical Cascade Versatile Alkylation of Quinoxalinones Enabled by Electron Donor Acceptor Complex in Water

A strategy for the synthesis of diverse protected α‐monofluoro‐γ‐amino acid derivatives has been developed. This reaction assembles a simple enamide, quinoxalin‐2(1H)‐one, and diethyl 2‐bromo‐2‐fluoromalonate through a three‐component reaction driven by visible light. The advantages of this protocol include the simplicity of its operation, mild conditions, high functional group tolerance, and applicability to a wide variety of substrates. The synthesis of this fluorine‐containing amino acid derivative has significant value for potential applications in medicinal chemistry and chemical biology.

Section: Resultsmentioning

confidence: 58%

Visible‐Light‐Driven Three‐Component Reaction of Unactivated Alkenes Enables Access to Monofluoro γ‐Amino Acids

Ju,

Huang,

Liu

et al. 2023

“…Regarding the reaction mechanism, a radical process was proposed by authors through a series of control experiments, the combination of CuCl and TBHP promoted the generation of α ‐amino radical, which abstracted a halogen atom from CHCl 3 to produce the CHCl 2 radical, finally, the desired product was obtained after radical addition and 1,2‐H shift (Scheme 18). In 2023, Jin and coworkers [36] described a similar protocol for three‐component alkylation of quinoxalin‐2(1 H )‐ones with diethyl α‐bromomalonate and unactivated alkenes under photoredox catalysts‐ and additive‐ free conditions (Scheme 19). The electron donor‐acceptor (EDA) complexes formed by quinoxalin‐2(1 H )‐ones and diethyl α‐bromomalonate promoted the formation of C‐centered alkyl radical species via a SET process.…”

Section: Carbon‐centered Radical Speciesmentioning

confidence: 99%

Three‐Component Reactions of Quinoxalin‐2(1H)‐ones: Recent Advances

Wang,

Ji,

et al. 2023

The multicomponent reactions of quinoxalin‐2(1H)‐ones has attracted considerable interest due to their significant biological and chemical activities. The very recent advances (from 2021 to the beginning of 2023) on the radical three‐component cascade reaction of quinoxalin‐2(1H)‐one derivatives at the C3 position were summarized in this mini‐review. According to the kind of radical types involved, some representative examples and detailed reaction mechanism have been categorized and discussed.The red front was covered by Figure 1.

“…[49] In 2023, the group of Can Jin also reported a multicomponent cascade mediated by visible light for the alkylation of quinoxalinones 73 in water (Scheme 28 bottom). [50] Previously, visible light photoredox catalysis was exploited for the functionalization of quinoxalin-2(1H)-one derivatives, but always in the presence of a catalyst or an additive, except for the example reported by Studer et al (Scheme 28 top). [51] In this case, perfluoroalkylated quinoxalinones 76 were obtained in mild conditions by a three-component radical cascade under blue light-irradiation and in the presence of DBU as a base able to deprotonate the key acidic aminyl radical intermediate.…”

Section: Miscellaneous Synthesis Of N-containing Heterocyclesmentioning

confidence: 99%

“…In 2023, the group of Can Jin also reported a multicomponent cascade mediated by visible light for the alkylation of quinoxalinones 73 in water (Scheme 28 bottom) [50] . Previously, visible light photoredox catalysis was exploited for the functionalization of quinoxalin‐2(1 H )‐one derivatives, but always in the presence of a catalyst or an additive, except for the example reported by Studer et al.…”

Section: Nitrogen Heterocyclesmentioning

confidence: 99%

Light‐Induced Domino and Multicomponent Reactions: How to Reach Molecular Complexity without a Catalyst

Renzi,

Scarfiello,

Lanfranco

et al. 2023

Achieving high molecular complexity can be not trivial, but the exploitation of domino reactions provides an atom‐ and step‐economical method to reach this target. Over the past decades, a lot of efforts have been put on the development of photocatalytic cascades employing both metal‐based and purely organic catalysts. Despite the effectiveness of these protocols, catalyst‐ and additive‐free light‐induced domino reactions are gaining momentum thank to their efficiency, operational simplicity and sustainability. The increasing number of papers published on this field in the last years is a proof of the appeal of these transformations. In this Review, we discuss domino and multicomponent reactions mediated by light with a focus on photocatalyst‐ and additive‐free processes. The most recent advances in the synthesis of complex nitrogen‐, oxygen‐, sulphur/selenium‐heterocycles together with multicomponent cascades are analysed with an emphasis on both experimental and mechanistic studies.