Catalyst-Free Organic Transformations under Visible-Light

ACS Sustainable Chemistry & Engineering, Journal Year: 2021, Volume and Issue: 9(12), P. 4296 - 4323

Published: March 16, 2021

Pollutants from industry and chemical laboratories have harmful effects on human health the environment. Concerns about this problem led to development of more versatile sustainable protocols based principles green chemistry. One these innovative approaches is carry out reactions under visible-light sources without photocatalysts. This benign, simple, cost-effective method, inspired by nature, could be a suitable alternative some classical methods, change harsh reaction conditions into milder ones. In Perspective, we outlined results catalyst-free organic further encourage researchers in promising field. The proposed mechanisms generation an electron donor–acceptor complex (EDA) single-electron transfer (SET) pathway were discussed.

Language: Английский

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Blue Light‐Promoted N−H Insertion of Carbazoles, Pyrazoles and 1,2,3‐Triazoles into Aryldiazoacetates

Advanced Synthesis & Catalysis, Journal Year: 2019, Volume and Issue: 362(5), P. 1106 - 1111

Published: Dec. 23, 2019

Abstract Blue light irradiation of aryldiazoacetates leads to the formation free carbenes, which can react with carbazoles, pyrazoles and 1,2,3‐triazoles afford corresponding N−H inserted products. These reactions are performed under air at room temperature, allowing mild preparation a variety motifs found in biologically relevant targets. magnified image

Language: Английский

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Stoichiometric Photochemical Carbene Transfer by Bamford–Stevens Reaction

Chemistry - A European Journal, Journal Year: 2019, Volume and Issue: 26(12), P. 2586 - 2591

Published: Dec. 11, 2019

The photolysis of diazoalkanes is a timely strategy to conduct carbene-transfer reactions under mild and metal-free reaction conditions, has developed as an important alternative conventional metal-catalyzed reactions. One the major limitations lies within rapidly occurring side carbene intermediate with remaining diazoalkane molecules that result in use excess partner thus impacts on efficiency. Herein, we describe protocol takes advantage situ generation donor-acceptor by Bamford-Stevens reaction. Following this strategy, concentration can be minimized reduce unwanted now photochemical transfer stoichiometric conditions. We have explored approach C-H N-H functionalization cyclopropanation N-heterocycles could demonstrate applicability method 51 examples.

Language: Английский

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Divergent Synthesis of Aziridine and Imidazolidine Frameworks under Blue LED Irradiation

Organic Letters, Journal Year: 2021, Volume and Issue: 23(11), P. 4109 - 4114

Published: May 14, 2021

We develop a visible light-promoted divergent cycloaddition of α-diazo esters with hexahydro-1,3,5-triazines, leading to series aziridine and imidazolidine frameworks in average good yield, by simply changing the reaction media used. It is noteworthy that occurs under sole light irradiation without need for exogenous photoredox catalysts. More significantly, reasonable mechanism was proposed on basis control experiments density functional theory calculation results.

Language: Английский

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Visible Light-Promoted Transformation of Diazo Compounds via the Formation of Free Carbene as Key Intermediate

Chinese Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 41(12), P. 4565 - 4565

Published: Jan. 1, 2021

Carbene is one of the most important synthetic intermediates in organic synthesis.In past few decades, transition-metal catalyzed carbene transfer reactions have made remarkable development.Recently, visible light-promoted transformation diazo compounds through formation free as key intermediate begun to rise.The reaction only need light sole energy source which meets concept green chemistry.Since pioneering works developed by groups Diaves and Zhou, photo-promoted has attracted more attentions.On basis previous work, latest progress this field further improved, mainly focuses on recent new under irradiation contributions reported from Chinese research group.The future development direction, well challenges prospected.

Language: Английский

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Oxime Ether Synthesis through O–H Functionalization of Oximes with Diazo Esters under Blue LED Irradiation

Organic Letters, Journal Year: 2021, Volume and Issue: 23(17), P. 6951 - 6955

Published: Aug. 12, 2021

A green and sustainable oxime ether formation method via the visible-light-promoted O–H functionalization of oximes with diazo esters is described. The reaction occurs under very mild conditions (catalyst- additive-free) a high yield functional group tolerance. When was performed cyclic as solvent (e.g., THF, 1,4-dioxane, tetrahydropyran, ect.), an interesting photochemical three-component product obtained in good yields.

Language: Английский

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Photocatalytic gem‐Difluoroolefination Reactions by a Formal C−C Coupling/Defluorination Reaction with Diazoacetates

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(4)

Published: Oct. 30, 2021

The photolysis of diazoalkanes to conduct singlet carbene transfer reactions colored has recently attracted significant interest in organic synthesis. Herein, we describe a photocatalytic approach that allows the access triplet intermediates via energy highly efficient gem-difluoroolefination with α-trifluoromethyl styrenes. use tertiary amines proved pivotal unlock this unusual reaction pathway and prevent undesired cyclopropanation pathways. amine further facilitates ultimate abstraction fluoride yield gem-difluoroolefins (43 examples, up 88 % yield), which is supported by experimental theoretical mechanistic studies. We explored synthesis method broad substrate scope, ranging from simple olefins heterocyclic towards decoration pharmaceutically relevant building blocks.

Language: Английский

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Visible-Light-Mediated Formal Carbene Insertion Reaction: Enantioselective Synthesis of 1,4-Dicarbonyl Compounds Containing All-Carbon Quaternary Stereocenter

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(9), P. 5510 - 5516

Published: April 25, 2022

We developed an efficient visible-light-mediated formal carbene insertion reaction of 1,3-diketones with diazoesters for the construction enantioenriched 1,4-dicarbonyl compounds a quaternary carbon center. Combining visible light and Brønsted acid catalyst, chiral were achieved in good yields high enantioselectivities by photochemical transfer protocol.

Language: Английский

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A Spiro Phosphamide Catalyzed Enantioselective Proton Transfer of Ylides in a Free Carbene Insertion into N−H Bonds

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(15)

Published: Feb. 14, 2023

Free carbene readily causes multiple side reactions due to its high energy, thus asymmetric transformation is very difficult. We present here our findings of high-pKa Brønsted acid catalysts that enable free insertion into N-H bonds amines prepare chiral α-amino derivatives with enantioselectivity. Under irradiation visible light, diazo compounds produce high-energy carbenes are captured by form ylide intermediates, and then the newly designed acids, spiro phosphamides, promote proton transfer ylides afford products. Computational kinetic studies uncover principle for rational design proton-transfer explain how accelerate this provide stereocontrol.

Language: Английский

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Visible photons as ideal reagents for the activation of coloured organic compounds

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(10), P. 4926 - 4975

Published: Jan. 1, 2024

In search for the perfect wave(length). This review is dedicated to recent efforts in development of visible light driven photochemical strategies occurring coloured organic compounds.

Language: Английский

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