Bicyclic Piperidines <i>via</i> [2 + 2] Photocycloaddition

Shcherbakova, Valeriya; Dibchak, Dmitry; Snisarenko, Mariya; Skalenko, Yevhen; Denisenko, Aleksandr V.; Kuznetsova, Anastasiia S.; Mykhailiuk, Pavel K.

doi:10.1021/acs.joc.0c02355

Cited by 10 publications

(3 citation statements)

References 64 publications

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“…Hence, these protocols are usually inherently limited to dienes containing appropriate functional groups. For example, enones which require UV light (λ = 300–350 nm) have been extensively explored, while the use of conjugated dienes which require higher-energy UV-C light (λ = 240–265 nm) has emerged more recently . Despite significant progress in this area, protocols suitable for simple unconjugated or unactivated olefins remain unpractical for most photocatalytic protocols due to the short-wave optical transitions (λ < 200 nm).…”

Section: Introductionmentioning

confidence: 99%

“…Herein, we report an efficient iron-catalyzed method for the synthesis of a diverse range of conformationally restricted cyclobutane-fused N-heterocycles. This method not only improves upon the previously reported turnover frequency (TOF) but also allows the use of unactivated precursors to gain access to cyclobutane-fused piperidines and previously unattainable azepanes, which are not generally accessible through conventional thermal or photochemical methods …”

Section: Introductionmentioning

confidence: 99%

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Iron-Catalyzed Synthesis of Conformationally Restricted Bicyclic N-Heterocycles via [2+2]-Cycloaddition: Exploring Ring Expansion─Mechanistic Insights and Challenges

et al. 2023

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We present an efficient iron-catalyzed method for synthesizing conformationally restricted cyclobutane-fused Nheterocycles from unactivated precursors. This method is orthogonal to the established photocatalytic methods, extends the range of substrates, and provides a single-step route to previously unattainable cyclobutane-fused piperidines and azepanes. Ring stereochemistry depends on size, with five-and sixmembered rings adopting a cis configuration and seven-membered rings preferring a trans configuration. A key aspect of this method is the use of a catalyst design based on an electron-deficient, redoxactive, pyrimidinediimine scaffold. Mechanistic investigations suggest that the π-acidic core significantly enhances catalyst stability against deleterious intramolecular C−H activation pathways, while the electron-rich flanking groups accelerate the reaction rate. Mechanistic insights were obtained by extracting kinetic profiles and establishing catalyst−activity relationships. Computational studies established that the oxidative cyclization step proceeds with the highest energy barrier, which is further confirmed by experimental Hammett analysis.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Iron-Catalyzed Synthesis of Conformationally Restricted Bicyclic N-Heterocycles via [2+2]-Cycloaddition: Exploring Ring Expansion─Mechanistic Insights and Challenges

et al. 2023

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“… 14 However, the need to use (a) the broad wavelength mercury lamp and (b) Pyrex glassware somewhat complicated the practical aspects of the procedure. Out of curiosity, 23 we tried other standard wavelengths—420 and 365 nm—that are compatible with standard chemical glassware and do not require Pyrex vessels. Under irradiation with 420 nm (blue LED), the reaction did not proceed.…”

Section: Resultsmentioning

confidence: 99%

Large-Scale Synthesis and Modifications of Bicyclo[1.1.1]pentane-1,3-dicarboxylic Acid (BCP)

et al. 2021

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In flow photochemical addition of propellane to diacetyl allowed construction of the bicyclo[1.1.1]pentane (BCP) core in a 1 kg scale within 1 day. Haloform reaction of the formed diketone in batch afforded bicyclo[1.1.1]pentane-1,3-dicarboxylic acid in a multigram amount. Representative gram scale transformations of the diacid were also performed to obtain various BCP-containing building blocks—alcohols, acids, amines, trifluoroborates, amino acids, etc .—for medicinal chemistry.

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Organophotocatalytic [2+2] Cycloaddition of Electron‐Deficient Styrenes**

Golfmann

Glagow

Giakoumidakis

et al. 2022

Chemistry A European J

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A visible‐light organophotocatalytic [2+2] cycloaddition of electron‐deficient styrenes is described. Photocatalytic [2+2] cycloadditions are typically performed with electron‐rich styrene derivatives or α,β‐unsaturated carbonyl compounds, and with transition‐metal‐based catalysts. We have discovered that an organic cyanoarene photocatalyst is able to deliver high‐value cyclobutane products bearing electron‐deficient aryl substituents in good yields. A range of electron‐deficient substituents are tolerated, and both homodimerisations and intramolecular [2+2] cycloadditions to fused bicyclic systems are available by using this methodology.

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Bicyclic Piperidines via [2 + 2] Photocycloaddition

Cited by 10 publications

References 64 publications

Iron-Catalyzed Synthesis of Conformationally Restricted Bicyclic N-Heterocycles via [2+2]-Cycloaddition: Exploring Ring Expansion─Mechanistic Insights and Challenges

Iron-Catalyzed Synthesis of Conformationally Restricted Bicyclic N-Heterocycles via [2+2]-Cycloaddition: Exploring Ring Expansion─Mechanistic Insights and Challenges

Large-Scale Synthesis and Modifications of Bicyclo[1.1.1]pentane-1,3-dicarboxylic Acid (BCP)

Organophotocatalytic [2+2] Cycloaddition of Electron‐Deficient Styrenes**

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