66-39-7Relevant articles and documents
Ceramic boron carbonitrides for unlocking organic halides with visible light
Yuan, Tao,Zheng, Meifang,Antonietti, Markus,Wang, Xinchen
, p. 6323 - 6332 (2021/05/19)
Photochemistry provides a sustainable pathway for organic transformations by inducing radical intermediates from substrates through electron transfer process. However, progress is limited by heterogeneous photocatalysts that are required to be efficient, stable, and inexpensive for long-term operation with easy recyclability and product separation. Here, we report that boron carbonitride (BCN) ceramics are such a system and can reduce organic halides, including (het)aryl and alkyl halides, with visible light irradiation. Cross-coupling of halides to afford new C-H, C-C, and C-S bonds can proceed at ambient reaction conditions. Hydrogen, (het)aryl, and sulfonyl groups were introduced into the arenes and heteroarenes at the designed positions by means of mesolytic C-X (carbon-halogen) bond cleavage in the absence of any metal-based catalysts or ligands. BCN can be used not only for half reactions, like reduction reactions with a sacrificial agent, but also redox reactions through oxidative and reductive interfacial electron transfer. The BCN photocatalyst shows tolerance to different substituents and conserved activity after five recycles. The apparent metal-free system opens new opportunities for a wide range of organic catalysts using light energy and sustainable materials, which are metal-free, inexpensive and stable. This journal is
Hantzsch Ester as a Visible-Light Photoredox Catalyst for Transition-Metal-Free Coupling of Arylhalides and Arylsulfinates
Zhu, Da-Liang,Wu, Qi,Li, Hai-Yan,Li, Hong-Xi,Lang, Jian-Ping
supporting information, p. 3484 - 3488 (2020/03/05)
Diethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (HEH) has been utilized as a visible-light photoredox catalyst for the cross coupling of arylhalides and arylsulfinates without transition metal, sacrificial agent, and mediator. This method is compatible with various functional groups and provides diaryl sulfones in good to high yields. Mechanistic studies indicate that this reaction undergoes the stepwise light irradiation of HE?, single electron transfer (SET) in donor–acceptor complex (DAC) from *HE? to arylhalide, trapping of aryl radical with sulfinate, and SET oxidation of sulfone radical anion by HE. to sulfone by the DAC method.
Engaging sulfinate salts via Ni/photoredox dual catalysis enables facile Csp2-SO2R coupling
Cabrera-Afonso, María Jesús,Lu, Zhi-Peng,Kelly, Christopher B.,Lang, Simon B.,Dykstra, Ryan,Gutierrez, Osvaldo,Molander, Gary A.
, p. 3186 - 3191 (2018/03/30)
This report details the development and implementation of a strategy to construct aryl- and heteroaryl sulfones via Ni/photoredox dual catalysis. Using aryl sulfinate salts, the C-S bond can be forged at room temperature under base-free conditions. An array of aryl- and heteroaryl halides are compatible with this approach. The broad tolerance and mild nature of the described reaction could potentially be employed to prepare sulfones with biological relevance (e.g., in bioconjugation, drug substance synthesis, etc.) as demonstrated in the synthesis of drug-like compounds or their precursors. When paired with existing Ni/photoredox chemistry for Csp3-Csp2 cross-coupling, an array of diverse sulfone scaffolds can be readily assembled from bifunctional electrophiles. A mechanistic manifold consistent with experimental and computational data is presented.
