Triarylamine-Substituted Benzimidazoliums as Electron Donor–Acceptor Dyad-Type Photocatalysts for Reductive Organic Transformations

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(18), P. 10236 - 10248

Published: May 2, 2023

Triarylamine-substituted benzimidazoliums (BI+-PhNAr2), new electron donor-acceptor dyad molecules, were synthesized. Their photocatalytic properties for reductive organic transformations explored using absorption and fluorescence spectroscopy, redox potential determinations, density functional theory calculations, transient reduction reactions of selected substrates. The results show that irradiation BI+-PhNAr2 promotes photoinduced intramolecular transfer to form a long-lived (∼300 μs) charge shifted state (BI•-PhN•+Ar2). In the pathway photocatalysis substrates, BI•-PhN•+Ar2 is subsequently transformed neutral benzimidazolyl radical (BI•-PhNAr2) by single-electron from donor 1,3-dimethyl-2-phenylbenzimidazoline (BIH-Ph) serving as cooperative agent. Among explored, bromo-substituted analogue BI+-PhN(C6H4Br-p)2 in conjunction with BIH-Ph demonstrates most consistent catalytic performance.

Language: Английский

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Photochemical halogen-bonding assisted carbothiophosphorylation reactions of alkenyl and 1,3-dienyl bromides

Chemical Science, Journal Year: 2023, Volume and Issue: 14(44), P. 12767 - 12773

Published: Jan. 1, 2023

Herein, we present a synthetic procedure for the facile and general preparation of novel S-alkenyl dienyl phosphoro(di)thioates first time. Extensive mechanistic investigations support that reactions rely on photochemical excitation halogen-bonding complex, formed with phosphorothioate salt an alkenyl or bromide, which light-induced fragmentation leads to formation desired products through radical-based pathway. The substrate scope is broad exhibits wide functional group tolerance in final compounds, including molecules derived from natural products, all unknown potentially interesting biological properties. Eventually, very efficient continuous flow protocol was developed upscale these reactions.

Language: Английский

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Photochemical halogen-bonding assisted generation of vinyl and sulfur-centered radicals: stereoselective catalyst-free C(sp²)–S bond forming reactions

Chemical Science, Journal Year: 2022, Volume and Issue: 14(3), P. 650 - 657

Published: Dec. 7, 2022

The combination of photochemistry and halogen bonding interactions has risen in the last few years as a powerful synthetic tool for creation radical intermediates under mild conditions. In formation carbon-centered radicals, this reactivity been to date restricted employment aryl alkyl halides precursors. We now envisioned that halogen-bonding initiated highly reactive vinyl radicals would be feasible process photochemical cross-coupling between thiols alkenyl basic reaction shows indeed very broad functional group tolerance, is stereoselective, simple scalable. In-depth mechanistic studies point at sulfur-centered DFT calculations support pre-formation complex initiator transformation. Synthetic applications were developed extend utility methodology.

Language: Английский

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Catalyst-free intramolecular radical cyclization cascades initiated by the direct homolysis of C_sp³–Br under visible light

Green Chemistry, Journal Year: 2023, Volume and Issue: 25(10), P. 3989 - 3994

Published: Jan. 1, 2023

A visible light-mediated C sp 3 –Br homolysis-initiated radical cyclization cascade delivering diverse 3-difluorolactam substituted chroman-4-ones with excellent regioselectivity and diastereoselectivity.

Language: Английский

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Perfluoroalkylation Reactions by Electron Donor‐Acceptor Complexes: Recent Advances

ChemPhotoChem, Journal Year: 2024, Volume and Issue: 8(8)

Published: May 3, 2024

Abstract This Perspective analyses the perfluoroalkylation reactions by electron donor‐acceptor (EDA) complexes since 2018, while summarizes, in Tables , vast majority of representative various classes organic compounds EDA and halogen‐bonding interactions. Numerous intriguing reaction methodologies valuable synthetic instances have emerged. We aim to delve into these new examples comprehensively, also contemplating future directions field. Subsequent sections will elaborate on (hetero)aromatic compounds, carbon‐carbon multiple bonds, carbonyl isocyanides, covering their scope mechanistic insights. Perfluoroalkylation complexes. Entry Substrate Complex Reaction conditions Product Ref. 1 [13] 2 [46] 3 R F I (3 equiv.) KOH (1.5 Blue LEDs H O, Ar, 20 h [47] 4 TEEDA CFL (25 W) THF, r.t. F− [48] 5 ICF CO Et (1.3 Na DMSO mL) rt. 427 nm LED, 16 [49] 6 TMG (2.5 23 W CFL, MeCN/Hex f (5 : 1) [42,50] 7 MeCN [51] 8 Umemoto's reagent (2 N ‐methylmorpholine DMF, [52] 9 Cs white light O r.t., [53] 10 4.5 450 laser CaCl MeNO 0 °C [3] 11 t ‐BuONa DMF Green [54] 12 or complex I−R (2.1 TMEDA DBU 24 [55,56] 13 TFE/water (1 (0.2 M) CF SO [84] bonds constrained cyclic Bu NCl, Hg lamp (6 (1.2 CH OH, 1.5 r.t, Ar [39] [57] DIPEA …….. −I Base THF 25 with DIPEA, TEEDA; [48,58,59] Bn NH [60] Base, [61] O/toluene=9 LEDs, 65 °C, [41] K PO CuCl (10 mol%) TMSNCS CN Violet (24 [37] Diphenylacetaldehyde Pyrrolidine (40 DCE mL); (0.8 eq.); White W); [44,62] DIPEA,DMA (trace air) 36–72 [63] n ‐C air, RT [64] DABCO υ (400 Watt) 50 C 2n+1 (1.8 [65–67] DCE, [27] 14 2,4,6‐trimethylpyridine MeCN, 60 Togni's [68] 15 PMDETA [69] [70,71] 17 less than % water mmol) isocyanides hydrazones. [72,73] cis ‐catalyst M (20 2,6‐lutidine (0.7 ‐10 [74] [75] phase transfer catalyst Cl/8F 18 1), [32] ambient NaOH (4.1 R.T. [76] 36 30 [77] I−C [78] [79] Imidazole [80]

Language: Английский

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α‐Halocarbonyls as a Valuable Functionalized Tertiary Alkyl Source

ChemistryOpen, Journal Year: 2024, Volume and Issue: unknown

Published: July 11, 2024

Abstract This review introduces the synthetic organic chemical value of α‐bromocarbonyl compounds with tertiary carbons. compound a carbon has been used primarily only as radical initiator in atom transfer polymerization (ATRP) reactions. However, recent development photo‐radical reactions (around 2010), research on use alkyl precursors became popular 2012). As more examples were reported, studied not radicals but also for their applications organometallic and ionic That is, act nucleophiles well electrophiles. The carbonyl group is attractive because it allows skeleton to be converted after reaction, being applied total synthesis. In our survey until 2022, can perform full range necessary synthesis, including multi‐component reactions, cross‐coupling, substitution, cyclization, rearrangement, stereospecific asymmetric α‐Bromocarbonyl have created new trend alkylation, which then had limited reaction patterns focuses how chemistry.

Language: Английский

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Visible Light‐ATRP Driven by Tris(2‐Pyridylmethyl)Amine (TPMA) Impurities in the Open Air

Macromolecular Rapid Communications, Journal Year: 2022, Volume and Issue: 44(16)

Published: Dec. 6, 2022

Atom transfer radical polymerization (ATRP) of oligo(ethylene oxide) monomethyl ether methacrylate (OEOMA500 ) in water is enabled using CuBr2 with tris(2-pyridylmethyl)amine (TPMA) as a ligand under blue or green-light irradiation without requiring any additional reagent, such photo-reductant, the need for prior deoxygenation. Polymers low dispersity (Đ = 1.18-1.25) are synthesized at high conversion (>95%) TPMA from three different suppliers, while no occurred and purified laboratory. Based on spectroscopic studies, it proposed that impurities (i.e., imine nitrone dipyridine), which absorb green light, can act photosensitive co-catalyst(s) light region where neither pure nor [(TPMA)CuBr]+ absorbs light.

Language: Английский

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Dual anion and cation catalysis enabled by an ion-pairing photocatalyst

Organic Chemistry Frontiers, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

A dual catalysis involving both anionic and cationic species of an ion-pairing photocatalyst is achieved. By adopting this mode action, photocatalytic hydrogen transfer cross-coupling reactions can be enabled using a single photocatalyst.

Language: Английский

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Benzophenothiazine/Boronic Acid Cooperative Photocatalysis Enables the Synthesis of γ-Lactones via the [3 + 2] Cycloaddition of α,β-Unsaturated Carboxylic Acids with Olefins

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 4975 - 4983

Published: March 10, 2025

Language: Английский

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Bulky Alkyl Substituents Enhance the Photocatalytic Activity of Pyridine-Based Donor–Acceptor Molecules in the Direct Reductive Cleavage of the C–Br Bond of Aliphatic Bromides

Organic Letters, Journal Year: 2024, Volume and Issue: 26(28), P. 5883 - 5887

Published: July 5, 2024

We report new pyridine-based donor-acceptor (D-A) molecules that enable the direct reductive transformation of a variety secondary and tertiary aliphatic bromides. A series experimental theoretical results suggested D-A promote C-Br bond cleavage triggered by excitation complex between catalyst bromide alkyl groups significantly contribute to stabilization complex, which improves efficiency its excitation.

Language: Английский

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