On the Route to the Photogeneration of Heteroaryl Cations. The Case of Halothiophenes

Raviola, Carlotta; Chiesa, Francesco; Protti, Stefano; Albini, Angelo; Fagnoni, Maurizio

doi:10.1021/acs.joc.6b00978

Cited by 4 publications

(1 citation statement)

References 65 publications

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“…Another functional previously employed for aryl cations, namely, M06‐2X, resulted in a shortening of the C‐Cl bond for both states. [ 55 ] The partial charges at the triplet stage differed from (U)B3LYP/6‐311+G(2d,p), with a charge underestimation at Cl and a negative sign at the ipso carbon. Next, the r 2 SCAN‐3c geometries were similar to the (U)B3LYP/6‐311+G(2d,p) references in terms of the C‐Cl bonds, atomic charges, and spins, while the triplet ring puckering was more pronounced.…”

Section: Resultsmentioning

confidence: 99%

Computational study on the reduction and solvolysis of triplet chlorobenzenes

Nitu

Crespi

2022

J of Physical Organic Chem

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In this work we explored the excited state reactivity of triplet chlorobenzenes with density functional theory and a cluster‐continuum approach. We modeled two competing reactions: a direct abstraction of hydrogen from a solvent molecule and solvolysis via photo‐SN2Ar. Electron donating (–OMe, –CH2SiMe3, –SiMe3) and withdrawing (–CN) substituents not only have distinct effects on the triplet geometries, inducing structural distortions due to the relief of excited state antiaromaticity, but also affect the reactivity of the system. Therefore, electron‐rich chlorobenzenes favor the radical reduction, while electron deficiency opens the possibility for solvolysis. Both reactions are energetically comparable to or more favorable then the dissociation of the C‐Cl bond to form triplet or singlet aryl cations, the intermediates considered responsible for these reactivities. Our findings can be correlated with experimental results on similar systems available from the literature, deeming the proposed pathways as viable alternatives to established mechanisms involving aryl cations.

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Section: Resultsmentioning

confidence: 99%

Computational study on the reduction and solvolysis of triplet chlorobenzenes

Nitu

Crespi

2022

J of Physical Organic Chem

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Photoinduced Cross-Coupling of Aryl Iodides with Alkenes

Liu

Chiba

2021

Org. Lett.

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A protocol for photoinduced cross-coupling of aryl iodides having polar π-functional groups or elongated π-conjugation with alkenes has been developed. The radical cascade mechanism involving generation of aryl radicals via C–I bond homolysis of photoexcited aryl iodides and their subsequent addition to alkenes is proposed. The method enables iodide-selective cross-coupling over other halogen leaving groups with functional group compatibility on both arene and alkene motifs.

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Search for a photoinduced (site-selective) cleavage of the Ar–Cl bond in dichloroanisoles

Raviola

Fagnoni

2018

Photochem Photobiol Sci

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The site-selective cleavage of an Ar-X bond in polyhalogenated aromatics is an important tool in synthetic planning especially when more than one identical halogen atom is present. An alternative to the usual metal-catalyzed cleavage is represented by photochemistry although only a few examples have been reported. We then investigated the feasibility of the site-selective photodechlorination of some dichloroanisoles through a combined experimental and computational study. In the case of 2,4-dichloroanisole, selective detachment of the chlorine atom at the ortho position with respect to the OMe group was observed upon photohomolysis (in cyclohexane) or photoheterolysis (in MeOH) of the Ar-Cl bond. In the latter case, 5-chloro-2-methoxy-1,1'-biphenyl was exclusively formed upon reaction of the resulting phenyl cation with benzene. The substitution of an OH group for a OMe group was detrimental since a lower photoreactivity resulted with no improvement in the selectivity.

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On the Route to the Photogeneration of Heteroaryl Cations. The Case of Halothiophenes

Cited by 4 publications

References 65 publications

Computational study on the reduction and solvolysis of triplet chlorobenzenes

Computational study on the reduction and solvolysis of triplet chlorobenzenes

Photoinduced Cross-Coupling of Aryl Iodides with Alkenes

Search for a photoinduced (site-selective) cleavage of the Ar–Cl bond in dichloroanisoles

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