Organocatalysis Meets Hydrocarbon Oxyfunctionalization: the Role of <i>N</i>‐Hydroxyimides

Andrade, Marta A.; Martins, Luísa M. D. R. S.

doi:10.1002/ejoc.202100479

Cited by 25 publications

(14 citation statements)

References 72 publications

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“…When reused with fresh substrate, the catalysts furnished a slightly lower yield with no loss in selectivity. Other solid supports, such as carbon materials and polymers, were later probed as well …”

Section: Achiral N-hydroxy Catalystsmentioning

confidence: 99%

“…Other solid supports, such as carbon materials and polymers, were later probed as well. 15 In summary, several strategies have been applied in the structural modification of NHPI derivatives. Specifically, electron-deficient groups were introduced to increase the BDEs of O−H bonds, which increased the hydrogen abstracting ability.…”

Section: Structure Modification To Promote Effective Collisionmentioning

confidence: 99%

“…Notably, the hydrogen-abstracting ability of N -oxyl is closely related to its electronic property. − Specifically, hydrogen abstraction by electron-rich N -oxyl compounds such as 2,2,6,6-tetramethylpiperidine- N -oxyl (TEMPO) or related dialkyl nitroxides can only be achieved at activated C–H positions; by contrast, an electron-deficient N -oxyl represented by phthalimido- N -oxyl (PINO) was capable of activating comparably unactivated C–H bonds (Figure ). In fact, since its first use as hydrogen abstractor in 1977, PINO has been widely explored − and has stimulated the exploration of N -hydroxy hydrogen abstractors. The high activity of PINO was ascribed to the high bond dissociation energy (BDE) − of the O–H bond in parent N -hydroxyphthalimide (NHPI), which is induced by the two adjacent electron-withdrawing carbonyl groups.…”

Section: Introductionmentioning

confidence: 99%

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Development of N-Hydroxy Catalysts for C–H Functionalization via Hydrogen Atom Transfer: Challenges and Opportunities

Luan

2022

ACS Catal.

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C–H functionalization via hydrogen atom transfer is an attractive method of decorating inert C–H bonds, yet it remains challenging so far. In such a reaction, the hydrogen abstractor generally plays a crucial role in determining the reactivity and selectivity. Among the various hydrogen abstractors developed, N-hydroxyphthalimide (NHPI) bearing an N-hydroxy group and two adjacent carbonyl groups has features including easy preparation, convenient modification, and a superior catalytic ability in many reactions. A large variety of electron-deficient N-hydroxy catalysts based on NHPI, including NHPI derivatives and analogues, have been successively developed and applied in a broad range of C–H functionalization reactions. This review comprehensively summarizes the development of N-hydroxy catalysts, with a special focus on the relationship between structure and performance.

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Section: Achiral N-hydroxy Catalystsmentioning

confidence: 99%

Section: Structure Modification To Promote Effective Collisionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Development of N-Hydroxy Catalysts for C–H Functionalization via Hydrogen Atom Transfer: Challenges and Opportunities

Luan

2022

ACS Catal.

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“…Various promoters such as Co(OAc) 2 and NO 2 by Ishii, , OsO 4 by Mayer, anthraquinones by Xu, , TBU by Kang, porphyrin-biscopper hexaphyrin by Ji, and so forth were reported to be able to promote the generation of the PINO radical and to improve the catalytic activity greatly. Second, supplying more reactive PINO or PINO-like radicals through the design of a novel precursor of organic N -hydroxyl compounds is another strategy to improve the catalytic activity. − TCNHPI, NHQI, and NDHPI in our previous work − and F-NHPI, C 2 -symmetric NHPI analogues, or TJU-68-NHPI could all show higher catalytic activity than NHPI especially in the oxidation of inert hydrocarbons. However, PINO is over-reactive and short-lived, which has caused a limited operational utility for methodology development due to the decomposition of PINO or side reactions. , Developing methods to improve catalysis through extending the lifetime of PINO emerged as the third approach, which has started to attract people’s attention quite recently.…”

Section: Introductionmentioning

confidence: 96%

Photo- and Solvent-Mediated Production of the Highly Reactive N-Oxyl Radical and Its Efficient Catalytic Oxidation of Hydrocarbons at Ambient Temperature

Zhu

Zhang

Xie

et al. 2022

ACS Sustainable Chem. Eng.

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Selective oxidation of hydrocarbons with molecular oxygen at ambient temperature is full of challenge, and efficient activation of the inert C−H bond under mild conditions is the breakthrough point. Due to the promotion effect of the organic solvent hexafluoroisopropanol (HFIP) and α-Fe 2 O 3 , highly reactive phthalimide-N-oxyl radical (PINO) species were produced under the photoirradiation of blue light (455 nm, 3 W) without additional heating, which were utilized to activate various aromatic hydrocarbons. Combining with the hyperoxide decomposition catalysis, the excellent conversion (98%) and the total selectivity (99%) to the ketone (aldehyde) and alcohol were successfully obtained at the ambient temperature of 30 °C. It was found that the reactivity and lifetime of PINO was closely related with the adsorption attitude of PINO on the surface of α-Fe 2 O 3 , which could be modulated to be most beneficial for the catalytic efficiency by relying on the homogeneous interaction between PINO and HFIP and the heterogeneous interaction between PINO and the surface of α-Fe 2 O 3 .

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“…In comparison with common spherical immobilized materials including silica and polymeric spheres, , biomass-derived NPCSs could be a promising selection for heterogeneous catalysts by virtue of their sustainability, low cost, high chemical resistance, good mechanical strength, and adsorption performance . Previous NHPI-anchored catalysts usually involved environment-unfriendly metallic chemicals, and developing efficient heterogeneous catalytic systems under nonmetallic conditions was highly alluring from the perspective of green catalysis. To the best of our knowledge, NPCS-supported NHPI and their application in nonmetal aerobic oxidation of hydrocarbons were hardly reported.…”

Section: Introductionmentioning

confidence: 99%

Universal Mass Production of Biomass-Derived Nanosized Porous Carbon Spheres as a Superior Nonmetal Catalyst for Aerobic Oxidation of Hydrocarbons

Shao

et al. 2022

ACS Sustainable Chem. Eng.

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The microscopic quantum effect, spherical morphology, and fast mass transfer properties render nanosized porous carbon spheres (NPCSs, <100 nm) of great utilitarian value in numerous applications, including catalysis. However, the preparation of monodisperse NPCSs was typically low output and high cost due to their large surface energy along with nanosized particles. In this study, we designed a high-yield hydrothermal carbonization process of soluble starch with the aid of poly-(diallyldimethylammonium chloride) to fabricate monodisperse carbonaceous spheres with a tunable nanosize of 43−97 nm. This synthesis still functioned well at starch concentrations as high as 520 g/L and in a 10-fold extended experiment with a yield of 49.1 g. The proposed methodology showed good versatility among various biomass-based carbon sources, including glucose, maltose, glucan, potato starch, barley starch, and corn starch. The subsequent static-air calcinations could facilely introduce rich mesoporosity onto nanosized carbonaceous spheres. N-Hydroxyphthalimide (NHPI) covalently anchored on NPCSs were first prepared as heterogeneous catalysts by polyamidamine dendrimer-based quaternization and amidate modification with 4-carboxyl-NHPI. These dendrimeric NPCSs contributed to the high NHPI loading (6.09 mmol/g). The synergistic effects between the loaded NHPI and the quaternized dendrimer afforded 45% conversion and 72% selectivity in the catalytic oxidation of ethylbenzene into acetophenone at 95 °C under 1 atm O 2 for 16 h, which was superior to the performance of unsupported NHPI. This anchored NHPI demonstrated good catalytic oxidation performance for various hydrocarbons and favorable reusability in a nine-run test. Their positively charged surface could prevent nanocatalyst agglomeration during the catalytic process. The nonmetal system, sustainable high-yield nanocarrier material, and high-loading active catalyst with good reusability are the advantages of the designed catalysis.

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Organocatalysis Meets Hydrocarbon Oxyfunctionalization: the Role of N‐Hydroxyimides

Cited by 25 publications

References 72 publications

Development of N-Hydroxy Catalysts for C–H Functionalization via Hydrogen Atom Transfer: Challenges and Opportunities

Development of N-Hydroxy Catalysts for C–H Functionalization via Hydrogen Atom Transfer: Challenges and Opportunities

Photo- and Solvent-Mediated Production of the Highly Reactive N-Oxyl Radical and Its Efficient Catalytic Oxidation of Hydrocarbons at Ambient Temperature

Universal Mass Production of Biomass-Derived Nanosized Porous Carbon Spheres as a Superior Nonmetal Catalyst for Aerobic Oxidation of Hydrocarbons

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