Aryl radical cation promoted remote dioxygenation of cyclopropane derivatives

Pan, Chengkai; Xu, Yao; Zhang, Bin; Ge, Liang; Zhang, Chi; Feng, Chao

doi:10.1016/j.xcrp.2022.101233

Cited by 11 publications

(10 citation statements)

References 66 publications

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“…This chiral complex enabled the control of both chemo-and enantioselectivity. This CF 3 -radical-mediated asymmetric alkene oxytrifluoromethylation reaction proceeds to produce CF 3 -substitued isoxazolines (88) with quaternary stereocenters in good yield with excellent enantiomeric excess. In the proposed mechanism, the key steps involve the intermolecular addition of the CF 3 radical to the alkene and the subsequent intramolecular coupling of the generated benzylic radical with the oxime via a Cu(III) intermediate (87-B).…”

Section: O-nucleophile-basedmentioning

confidence: 99%

“…On this basis, they developed a photocatalytic remote radical dioxygenation of aryl cyclopropanes (122) using either an alcohol or water as the O-nucleophile in the presence of a stoichiometric amount of Cu(OTf) 2 as an oxidant (Scheme 8d). 88 This protocol provides access to a range of substituted 1,3-and 1,5dioxygenation products (127) in moderate to good yield. Mechanistically, the photoredox-catalyzed SET oxidation of the aryl cyclopropane 122 weakens the C−C bond in the cyclopropyl ring, making it prone to cleavage in the presence of a nucleophile.…”

Section: Photoinduced Copper-promoted Radical-mediated C−o Bond Forma...mentioning

confidence: 99%

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Emerging Trends in Copper-Promoted Radical-Involved C–O Bond Formations

2023

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The C−O bond is ubiquitous in biologically active molecules, pharmaceutical agents, and functional materials, thereby making it an important functional group. Consequently, the development of C−O bond-forming reactions using catalytic strategies has become an increasingly important research topic in organic synthesis because more conventional methods involving strong base and acid have many limitations. In contrast to the ionic-pathway-based methods, copper-promoted radical-mediated C− O bond formation is experiencing a surge in research interest owing to a renaissance in free-radical chemistry and photoredox catalysis. This Perspective highlights and appraises state-of-the-art techniques in this burgeoning research field. The contents are organized according to the different reaction types and working models.

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Section: O-nucleophile-basedmentioning

confidence: 99%

Section: Photoinduced Copper-promoted Radical-mediated C−o Bond Forma...mentioning

confidence: 99%

Emerging Trends in Copper-Promoted Radical-Involved C–O Bond Formations

2023

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“…In the presence of water and air and a Cu(II) salt, the β-hydroxy ketone 50 was obtained in good yield. 20 When the reaction was carried out in the presence of a disulfide, the cyclopropane underwent ring-opening to give tertiary alcohol 51. 21 In the presence of pyrazole, the reaction outcome could be altered to yield N-alkylated pyrazole 52.…”

Section: T H Imentioning

confidence: 99%

Catalytic Olefin Cyclopropanation with In Situ-Generated Dialkyl Diazomethanes via Co(II)-Based Metalloradical Catalysis

Cai,

Empel,

Jana

et al. 2023

ACS Catal.

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The synthesis of dialkyl-substituted cyclopropanes is an important challenge in synthesis with applications in drug discovery and agrochemistry. Herein, we report on the synthesis of gem-dialkyl cyclopropanes with in situ-generated dialkyl diazo compounds under Bamford−Stevens conditions. A simple cobalt catalyst was identified to be optimal to achieve high yields. Experimental and computational studies suggest the participation of a metalloradical reaction mechanism that facilitates the carbene transfer reactions and provides access to dialkyl-substituted cyclopropanes in a single step.

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“…6 Recently, with a stoichiometric amount of a Cu( ii ) salt as a mild oxidant and also a radical elaboration agent, 1,3/1,5-dietherification of aryl cyclopropane/1-aryl-2-alkenyl cyclopropane with benzylic C–O single bond formation was also successfully achieved. 7…”

Section: Introductionmentioning

confidence: 99%

“…6 Recently, with a stoichiometric amount of a Cu(II) salt as a mild oxidant and also a radical elaboration agent, 1,3/1,5-dietherification of aryl cyclopropane/1-aryl-2-alkenyl cyclopropane with benzylic C-O single bond formation was also successfully achieved. 7 With these preliminary successes and our abiding interest in developing strategically novel synthetic transformations with photoredox catalysis, 8 we surmised that a similar strategy could be applied for benzylic C-C bond construction. In this respect, the Studer group has reported an elegant cooperative NHC/photoredox catalysed ring-opening difunctionalization of aryl cyclopropanes with benzoylation at the benzylic site.…”

Section: Introductionmentioning

confidence: 99%