Recent advances in radical chemistry proceeding through pro-aromatic radicals

Bhunia, Anup; Studer, Armido

doi:10.1016/j.chempr.2021.03.023

Cited by 97 publications

(39 citation statements)

References 120 publications

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“…In contrast to the existing methods that rely on the intrinsic properties of amino acids,i ntroducing ap eptidyl radical at the N-terminus can be challenging under photoredox conditions.W er ationale that insertion of as uitable radical precursor,e .g.,1 ,4-substituted dihydropyridine (DHP), [25] onto the peptide N-terminus would promote an orthogonal reaction site in the presence of other labile residues.T he utility of 4-substituted DHPs in peptide functionalization has been sporadically explored. We recently disclosed that the C2 position of histidine can be chemoselectively functionalized with alkylated DHPs via the mediation of visible light, suggesting the high tolerance of radicals derived from DHPs in complex peptide settings.…”

Section: Introductionmentioning

confidence: 99%

Site‐Selective Itaconation of Complex Peptides by Photoredox Catalysis

et al. 2021

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Site-selective peptide functionalization provides astraightforwardand cost-effective access to diversify peptides for biological studies.A mong many existing non-invasive peptide conjugations methodologies,p hotoredoxc atalysis has emerged as one of the powerfula pproaches for site-specific manipulation on native peptides.Herein, we report ahighly Ntermini-specific method to rapidly access itaconated peptides and their derivatives through acombination of transamination and photoredox conditions.T his strategy exploits the facile reactivity of peptidyl-dihydropyridine in the complex peptide settings,c omplementing existing approaches for bioconjugations with excellent selectivity under mild conditions.D istinct from conventional methods,t his method utilizes the highly reactive carbamoyl radical derived from ap eptidyl-dihydropyridine.I na ddition, this itaconated peptide can be further functionalizedasaMichael acceptor to access the corresponding peptide-protein conjugate.

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Section: Introductionmentioning

confidence: 99%

Site‐Selective Itaconation of Complex Peptides by Photoredox Catalysis

et al. 2021

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“…First, this conversion is required to conform to the rule that aromaticity driving force surpasses the energy of breaking double bonds. [9][10][11] Second, endowing a PAH diradical with long air stability needs to elongate the distance between two radicals to lower the interaction, 12 since short-distance radical species tend to be reactive. To meet above requirements is either designing PAHs with large fused π moieties or introducing bulky groups to protect radicals.…”

Section: Introductionmentioning

confidence: 99%

Air Stable Chalcogen-Doped Rubicenes with Diradical Character

Ma¹,

Wang²,

Li³

et al. 2022

CCS Chem

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Air stable diradicaloid polycyclic aromatic hydrocarbons (PAHs) materials possess unique electronic and magnetic properties for various applications. In general, it is required to elongate conjugated distances between two radicals center to improve the air stability, complexing the synthetic procedures. Herein, the chalcogen containing rubicenes (O-, S-, and Se-rubicenes) were systematically investigated to understand the chalcogen effects on their physicochemical properties. Impressively, these rubicenes presented unprecedented diradical characters within one simple benzene ring and excellent air stabilities. Their diradical characters are manifested by single-crystal X-ray studies, variable temperature-nuclear magnetic resonance

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“…2-Substituted benzothiazolines (BTA, 6 ) have been used as alternative hydride sources to Hantzsch esters in transfer hydrogenation reactions. 20 More recently, these compounds have been used as hydrogen atom donors in photocatalytic reactions 21 requiring auxiliary thiyl radical carriers 21b or metal photocatalysts. 21a However, benzothiazolines have never been employed as self-sensitized photoreductants or in reductive decarboxylative reactions, as far as we know.…”

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confidence: 99%

“…The autonomous photoactivation of benzothiazoline 6a was unexpected on the basis of the previously known reactivity of these systems based on HAT followed by proaromatic radical reduction with auxiliary photosensitization or chain carriers. 21 Thus, photochemical studies were performed to investigate the mechanism of the photoreduction. UV–visible spectroscopy revealed that neither 2-phenylbenzothiazoline 6a nor NHPI-ester 3a absorb light effectively in the visible range ( Figure 1 A).…”

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confidence: 99%

Modular Enantioselective Synthesis of cis-Cyclopropanes through Self-Sensitized Stereoselective Photodecarboxylation with Benzothiazolines

Costantini

Mendoza

2021

ACS Catal.

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Chiral cis -cyclopropanes are strained rigid analogues of alkyl chains, whose study and application are limited by their difficult synthesis. A modular approach from olefin materials is enabled by the discovery of the electron donor–acceptor (EDA) interaction between 2-substituted benzothiazolines and N -hydroxyphthalimide esters. These complexes are activated by visible light without photocatalysts, and the benzothiazoline reagent plays a triple role as a photoreductant, a stereoselective hydrogen-atom donor, and a Brønsted acid. Beyond the enantioselective synthesis of cis -cyclopropanes, these results introduce benzothiazolines as accessible and easily tunable self-sensitized photoreductants.

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Recent advances in radical chemistry proceeding through pro-aromatic radicals

Cited by 97 publications

References 120 publications

Site‐Selective Itaconation of Complex Peptides by Photoredox Catalysis

Site‐Selective Itaconation of Complex Peptides by Photoredox Catalysis

Air Stable Chalcogen-Doped Rubicenes with Diradical Character

Modular Enantioselective Synthesis of cis-Cyclopropanes through Self-Sensitized Stereoselective Photodecarboxylation with Benzothiazolines

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