Formaldehyde‐Extruding Homolytic Aromatic Substitution via C→O Transposition: Selective ‘Traceless‐Linker’ access to Congested Biaryl Bonds

Poonpatana, Pabhon; Gomes, Gabriel; Hurrle, Thomas; Chardon, Kimhoa; Bräse, Stefan; Masters, Kye-Simeon; Alabugin, Igor V.

doi:10.1002/chem.201700085

Cited by 11 publications

(7 citation statements)

References 57 publications

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“…We believe that the aromatization back to the tropolone structure by C−O bond breaking can be the driving force in this process to obtain only product 7 . Similar outcomes were reported in the literature to support this type of bond scission [21–24] …”

Section: Resultssupporting

confidence: 84%

Regioselectivity Patterns in Radical Cyclization of Diosphenol Derivatives with Different Ring Size: A Combined Experimental and DFT Study

et al. 2021

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Radical cyclization reactions are still a challenging field in synthetic organic chemistry. Herein, the radical reactions of 6‐ and 7‐membered diosphenol derivatives (tropolone) with a significant difference in reactivity, ring size, aromaticity and stability were investigated. While the former produces a mixture of products including oxabicycloalkanones, the experimental work performed herein resulted with a single 2‐(3‐hydroxypropyl)cyclohepta‐2,4,6‐trienone product, regioselectively. DFT calculations (UM05/6‐311++G(d,p)) were performed following the experimental studies in order to describe the outcomes correctly. Therefore, all possible reaction pathways were investigated for both diosphenol and tropolone. The reaction barriers and intrinsic barriers from the Marcus theory were calculated to investigate the thermodynamic and intrinsic electronic effects to the experimental product distribution. Both experiment and theory show that the aforementioned systems have different selectivity routes governed by several factors. As a result of this comparative study, the charge distribution at the reactive atoms, entropy factors for cyclization vs termination and aromatization of the ring effects were found to be the driving factors for the observed regioselectivity.

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Section: Resultssupporting

confidence: 84%

Regioselectivity Patterns in Radical Cyclization of Diosphenol Derivatives with Different Ring Size: A Combined Experimental and DFT Study

et al. 2021

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“…Further applications of the phenanthroline/KOtBu system have recently been reported. 36,37 More generally, the formation of electron donors by dimerization of compounds, following deprotonation by a base, has also been extended to some solvents, e.g., DMF (26) 53 (see Scheme 13) when KOtBu is the base and, when KH is the base, to benzene. 38 In a similar manner, Murphy et al investigated the reactions of KOtBu with a range of other additives, 15,28 establishing evidence for the in situ formation of organic electron donors (Scheme 13).…”

Section: Short Review Syn Thesismentioning

confidence: 99%

Ground State Cross-Coupling of Haloarenes with Arenes Initiated by Organic Electron Donors, Formed in situ: An Overview

Nocera¹,

Murphy²

2019

Synthesis

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Many reactions have been discovered that lead to coupling of haloarenes to arenes using potassium tert-butoxide as the base, and one of a variety of organic compounds as an additive. The organic additive reacts with the base to form a strong organic electron donor in situ that initiates a base-induced homolytic aromatic substitution (BHAS) coupling reaction, by converting the haloarene into an aryl radical. This brief report presents an overview of the wide range of organic additives that can be used, and the organic electron donors that they form.

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“…When deprotonation with a subsequent upconversion is difficult, the mechanistic scenarios can become more complicated. For example, as a consequence of the ipso ‐selectivity of the radical attack shown in Scheme , there is no proton at the respective position in the delocalized π‐radical intermediate . Hence, the cascade continues through a radical fragmentation step that completes the O,C transposition route to the hindered biphenyl.…”

Section: Reductant Upconversion Can Fuel Catalytic Cyclesmentioning

confidence: 84%

Upconversion of Reductants

et al. 2019

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Electrons and photons are essential chemical "currencies" commonly traded in chemical transformations. The many applications of photon upconversion, i.e., conversion of low energy photons into high energy photons, raises the question about the possibility of "electron upconversion". In this review, we illustrate how reduction potential can be increased by using the free energy of exergonic chemical reactions. The electron (reductant) upconversion can produce up to ~20-25 kcal/mol of additional redox potential, creating powerful reductants under mild conditions. We will present the two common types of electron-upconverting systems - dissociative (based on unimolecular fragmentations) and associative (based on bimolecular formation of three-electron bonds). The possible utility of reductant upconversion encompasses redox chain reactions in electrocatalytic processes, photoredox cascades, design of peroxide-based medicines, firefly luminescence, and reductive repair of DNA photodamage.

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Formaldehyde‐Extruding Homolytic Aromatic Substitution via C→O Transposition: Selective ‘Traceless‐Linker’ access to Congested Biaryl Bonds

Cited by 11 publications

References 57 publications

Regioselectivity Patterns in Radical Cyclization of Diosphenol Derivatives with Different Ring Size: A Combined Experimental and DFT Study

Regioselectivity Patterns in Radical Cyclization of Diosphenol Derivatives with Different Ring Size: A Combined Experimental and DFT Study

Ground State Cross-Coupling of Haloarenes with Arenes Initiated by Organic Electron Donors, Formed in situ: An Overview

Upconversion of Reductants

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