Visible-Light-Induced Synthesis of Esters via a Self-Propagating Radical Reaction

The Journal of Organic Chemistry, Год журнала: 2025, Номер 90(4), С. 1616 - 1627

Опубликована: Янв. 16, 2025

We herein disclose a visible-light-induced synthesis of O-aryl esters through the cross-dehydrogenative coupling aldehydes with phenols using BrCCl3, in which phenolate functions as both substrate and photosensitizer. This transition-metal- photocatalyst-free esterification is suitable for wide range substrates gives moderate to excellent yields (up 95%). Mechanistic studies provided evidence self-propagating radical reaction involving homolytic cleavage aldehydic C–H bond formation acyl bromides. BrCCl3 serves an oxidant hydrogen atom transfer (HAT) agent.

Язык: Английский

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Identification of a Self-Photosensitizing Hydrogen Atom Transfer Organocatalyst System

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(14), С. 6566 - 6574

Опубликована: Март 31, 2022

We developed organocatalyst systems to promote the cleavage of stable C–H bonds, such as formyl, α-hydroxy, and benzylic through a hydrogen atom transfer (HAT) process without use exogenous photosensitizers. An electronically tuned thiophosphoric acid, 7,7'-OMe-TPA, was assembled with substrate or co-catalyst N-heteroaromatics bonding π–π interactions form electron donor–acceptor (EDA) complexes. Photoirradiation EDA complex induced stepwise, sequential single-electron (SET) processes generate HAT-active thiyl radical. The first SET from electron-rich naphthyl group 7,7'-OMe-TPA protonated second proton-coupled (PCET) acid moiety resulting radical cation. Spectroscopic studies theoretical calculations characterized stepwise mediated by short-lived intermediates. This organocatalytic HAT system applied four different carbon–hydrogen (C–H) functionalization reactions, hydroxyalkylation alkylation N-heteroaromatics, acceptorless dehydrogenation alcohols, benzylation imines, high functional tolerance.

Язык: Английский

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Visible light-mediated metal-free alkyl Suzuki–Miyaura coupling of alkyl halides and alkenylboronic acids/esters: a green method for the synthesis of allyl difluoride derivatives

Green Chemistry, Год журнала: 2023, Номер 25(9), С. 3453 - 3461

Опубликована: Янв. 1, 2023

Halogen bonding-assisted C sp 3 –Br homolysis and bromine radical-mediated oxidative deboronation make visible-light-driven photocatalyst-free alkyl Suzuki–Miyaura coupling of alkenylboronic acids/esters with α-bromodifluoroacylarenes accessible.

Язык: Английский

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Visible Light‐Induced Metal‐Free Fluoroalkylations

The Chemical Record, Год журнала: 2023, Номер 23(9)

Опубликована: Март 21, 2023

Abstract Fluoroalkylation is a crucial synthetic process that enables the modification of molecules with fluoroalkyl groups, which can enhance properties compounds and have potential applications in medicine materials science. The utilization visible light‐induced, metal‐free methods particular importance as it provides an environmentally friendly alternative to traditional eliminates risks associated metal‐catalyst toxicity. This Account describes our studies on fluoroalkylation processes, include use organic photocatalysts or EDA complexes. We utilized organophotocatalysts such Nile red, tri(9‐anthryl)borane, indole‐based tetracyclic complex, well catalyst‐free chemistry through photoactive halogen bond formation unconventional transient ternary complex nucleophilic source. A variety π‐systems including arenes/heteroarenes, alkenes, alkynes been successfully fluoroalkylated under developed reaction conditions.

Язык: Английский

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Harnessing photocatalytic and electrochemical approaches for C–H bond trifluoromethylation and fluoroalkylation

Organic Chemistry Frontiers, Год журнала: 2023, Номер 11(3), С. 954 - 1014

Опубликована: Дек. 14, 2023

The review summarises various photo- and electrochemical strategies for trifluoromethylation fluoroalkylation of different C(sp 3 )–H, 2 C(sp)–H bonds in several classes organic molecules.

Язык: Английский

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From photons to reactions: key concepts in photoredox catalysis

Chem Catalysis, Год журнала: 2024, Номер unknown, С. 101110 - 101110

Опубликована: Сен. 1, 2024

Язык: Английский

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Perfluoroalkylation Reactions by Electron Donor‐Acceptor Complexes: Recent Advances

ChemPhotoChem, Год журнала: 2024, Номер 8(8)

Опубликована: Май 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]

Язык: Английский

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Electron donor–acceptor complex-catalyzed photoredox reactions mediated by DIPEA and inorganic carbonates

Organic Chemistry Frontiers, Год журнала: 2022, Номер 9(19), С. 5264 - 5271

Опубликована: Янв. 1, 2022

A DIPEA–NHPI ester–inorganic carbonate catalytic EDA complex is reported as an efficient and sustainable radical generation platform for developing photocatalytic reactions.

Язык: Английский

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Visible-Light Photoredox Catalysis for the Synthesis of Fluorinated Aromatic Compounds

Catalysts, Год журнала: 2023, Номер 13(1), С. 94 - 94

Опубликована: Янв. 2, 2023

Fluorine-containing functional groups are important motifs influencing physical and biological properties of organic compounds. Visible-light photoredox catalysis as a powerful strategy for the activation small molecules contributed significantly to rapid progress new synthetic procedures allowing introduction fluorine atoms into substrates. In this review, we highlight distinct strategies transition metal- organic-photocatalytic fluorination arenes heteroarenes by broad range fluorinating The presented divided two groups. first group involves reactions enabling direct attachment CF3-, CnFm-, F-, CF3O-, CF3S-, SO2F- substituents various aromatic second presents tandem where formation system occurs after installation fluorine-containing on non-aromatic fragment molecule.

Язык: Английский

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Frustrated-radical-pair-initiated atom transfer radical addition of perfluoroalkyl halides to alkenes

Organic Chemistry Frontiers, Год журнала: 2023, Номер 10(15), С. 3861 - 3869

Опубликована: Янв. 1, 2023

We employed a frustrated radical pair to catalyze the atom-transfer addition of perfluoroalkyl halides alkenes, which furnished series fluoroalkylated compounds in high regioselectivity and high-to-excellent product yields.

Язык: Английский

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