Visible-Light Driven Photocascade Catalysis: Union of <i>N</i>,<i>N</i>-Dimethylanilines and α-Azidochalcones in Flow Microreactors

Borra, Satheesh; Chandrasekhar, D.; Adhikary, Susanta; Rasala, Sandeep; Gokulnath, Sabapathi; Maurya, Ram Awatar

doi:10.1021/acs.joc.6b02932

Cited by 44 publications

(22 citation statements)

References 52 publications

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“…Again, a large variety of aromatic substituents on the vinyl azide substrate as well as halogen and alkyl substituents on the aniline starting materials furnished the 1,3‐diazabicyclo[3.1.0]hexanes 69 in moderate to good yield. The authors were again able to increase the yield by 19 % absolute through application of photoflow conditions [31b] …”

Section: Three‐membered Ring Systemsmentioning

confidence: 92%

Strain Release Chemistry of Photogenerated Small‐Ring Intermediates

Luque

Paternoga

Opatz

2021

Chemistry A European J

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Photochemical processes, such as isomerizations and cycloadditions, have proven to be very useful in the construction of highly strained molecular frameworks. Photoinduced ring strain enables subsequent exergonic reactions which do not require the input of additional chemical energy and provides a variety of attractive synthetic options leading to complex structures. This review covers the progress achieved in the application of sequences combining excitation by ultraviolet light to form strained intermediates, which are further transformed to lower energy products in strain‐release reactions. As ring strain is considerable in small ring systems, photogenerated three‐ and four‐membered rings will be covered, mainly focusing on examples from 2000 to May 2020.

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Section: Three‐membered Ring Systemsmentioning

confidence: 92%

Strain Release Chemistry of Photogenerated Small‐Ring Intermediates

Luque

Paternoga

Opatz

2021

Chemistry A European J

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“…Besides the general sustainability improvements mentioned above (no chromatography for product isolation; solvent-free and mild reaction conditions), some interesting and specific physical chemistry-based approaches in the synthesis of 3-arylated aziridine products have been reported. Thus, α-keto vinyl azides 25 react in the presence of tert -buthyl hydroxy peroxide and photocatalyst tris-(2.2′-bipyridine)ruthenium (II) hexafluorophosphate with 1.2.3.4-tetrahydro-β-carbolines [ 51 ] or dimethylanilines 26 [ 52 ] under white LED light irradiation forming corresponding bicyclic aziridine products 1a9 [ 52 ] (20 examples) or more complex fused aziridine systems 27 [ 51 ] (18 examples) in good yields ( Scheme 33 ).…”

Section: Perspective Photo- and Electrochemical Methods In The Synthe...mentioning

confidence: 99%

“…Studies of the reaction mechanism were performed [ 52 ]. It was proved in a single example that, in the presence of visible light and ruthenium photocatalyst, α-azidochalcone 25 got converted into 2H-azirine 9d via photosensitized decomposition.…”

Section: Perspective Photo- and Electrochemical Methods In The Synthe...mentioning

confidence: 99%

Non-Aziridination Approaches to 3-Arylaziridine-2-carboxylic Acid Derivatives and 3-Aryl-(aziridin-2-yl)ketones

Strumfs

Velikijs

Uljanovs

et al. 2022

IJMS

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Highly functionalized aziridines, including compounds with aromatic moieties, are attractive substrates both in synthetic and medical areas of chemistry. There is a broad and interesting set of synthetic methods for reaching these compounds. Aziridination represents the most explored tool, but there are several other more specific, less well-known, but highly promising approaches. Therefore, the current review focuses on recently described or updated ways to obtain 3-arylated aziridines via different non-aziridination-based synthetic methods, reported mainly since 2000. The presented methods belong to two main directions of synthesis, namely, cyclization of open-chain substrates and rearrangement of other heterocycles. Cyclization of open-chain substrates includes the classic Gabriel-Cromwell type cyclization of halogenated substrates with amines, base-promoted cyclization of activated aminoalcohols (or its analogues), and the oxidative cyclization of β-dicarbonyls. Rearrangements of other heterocycles are presented as the Baldwin rearrangement of 4-isoxazolines, the cycloaddition of 1.3-dipoles or dienes to 2H-azirines, and the addition of C- and N-nucleophiles to the double bond of azirines.

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“…Another photocatalytic flow process was used to synthesize bicyclic aziridines from N , N ‐dimethylanilines and α‐azidochalcones, using the same catalyst and photosensitizer described. The resulting 1,3‐diazabicyclo[3.1.0]hexane derivatives were prepared in good yields (Scheme ) …”

Section: Heterocyclic Synthesismentioning

confidence: 99%

Flow Chemistry: Towards A More Sustainable Heterocyclic Synthesis

2019

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Flow Chemistry is a revolutionary field in Organic Chemistry. By changing the conventional methods and apparatus applied in the chemical synthesis, flow chemistry emerges as a game changer for organic synthesis laboratories, in both academia and industries. Considered as a sustainable practice, flow processes play an important role in the development of fine chemical products and in drug discovery development pro- [a] The main advantages of flow chemistry are that it allows the reaction to be carried out safely with high selectivity, high reproducibility and reduced energy consumption/carbon footprint. These features make this emerging technology for organic synthesis desirable for green and sustainable chemical synthesis, giving the chemist time for work planning and design, instead of using it in repetitive tasks, [5b,12] as expressed by the CHEM21 project by awarding a green flag for continuousflow reactions, in opposition to an amber flag for those performed under batch conditions. [13] Pedro Brandão received his MSc in Pharmaceutical Sciences from the Faculty of Pharmacy -University of Porto, in 2011. Pursuing his passion on studies in the field of Drug Discovery and Development, he is currently undergoing his PhD studies in Chemistry, in the field of Catalysis and Sustainability. His main focus of work is the discovery of new drug candidates through sustainable techniques. Marta Pineiro received her Ph.D. in Organic Chemistry in 2003 in the University of Coimbra, Portugal, and since 2002 has been enrolled at the University of Coimbra, being at present Auxiliary Professor. Her research interests are in the area of sustainable organic synthesis, microwave-assisted organic synthesis and synthesis and biological applications of tetrapyrrolic macrocycles. Teresa M. V. D. Pinho e Melo studied Chemistry at the University of Coimbra, where she graduated in 1985, got her M. 7191CPBA) as the oxidizing agent, avoiding the handling of this expensive and explosive reagent. [25] Recently, Morodo et al. explored the synthesis of two very important oxiranes (epichlorohydrin and glycidol) from biobased glycerol, under flow conditions. As depicted in Scheme 1, and using pimelic acid as the catalyst (10 mol-%), a sequential hydrochlorination/dichlorination process allows high conversion of glycerol (> 99 %) into 1,3-dichloro-2-propanol, followed by the quantitative conversion into a separable mixture of glycidol and epichlorohydrin (2:3). The separation of these two products is performed by an in-line membrane separation system, which allows the first product to be collected in the aqueous phase, while the second is collected in MTBE. This heterocycle can be further used as a synthetic precursor to relevant APIs bearing -amino alcohol moieties (e.g., propranolol, alprenolol and naftopidil). [26] Scheme 1. Sequential flow setup for the preparation of glycidol and epichlorohydrin, important APIs synthetic intermediates.Scheme 3. Synthesis and inline purification of a bicyclic aziridine (SGMR = silicon-glass microfluidic react...

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Visible-Light Driven Photocascade Catalysis: Union of N,N-Dimethylanilines and α-Azidochalcones in Flow Microreactors

Cited by 44 publications

References 52 publications

Strain Release Chemistry of Photogenerated Small‐Ring Intermediates

Strain Release Chemistry of Photogenerated Small‐Ring Intermediates

Non-Aziridination Approaches to 3-Arylaziridine-2-carboxylic Acid Derivatives and 3-Aryl-(aziridin-2-yl)ketones

Flow Chemistry: Towards A More Sustainable Heterocyclic Synthesis

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