Hexafluoroisopropanol‐Promoted or Brønsted Acid‐Mediated Photochemical [2+2] Cycloadditions of Alkynes with Maleimides

ChemSusChem, Год журнала: 2022, Номер 15(4)

Опубликована: Янв. 3, 2022

Although the use of light stimulating organic transformations has been known for more than a century, there is an increasing research interest on expanding established knowledge. While [2+2] cycloadditions are promoted photochemically, literature precedent reaction between alkynes and maleimides limited only handful examples exist, focusing mainly N-aliphatic maleimides. Herein, differences in reactivity N-alkyl N-aryl were identified, hexafluoroisopropanol (HFIP) or trifluoroacetic acid (TFA) as viable solutions was proposed order to achieve high yields. In case maleimides, both HFIP-mediated TFA-promoted reactions using LED 370 nm irradiation, without external photocatalyst. thioxanthone (THX) employed energy transfer photocatalyst along with 427 irradiation HFIP. Mechanistic studies performed, supporting pivotal role HFIP TFA, acquiring good yields classes

Язык: Английский

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Dioxygen-promoted cobalt-catalyzed oxidative hydroamination using unactivated alkenes and free amines

Chem Catalysis, Год журнала: 2022, Номер 2(2), С. 345 - 357

Опубликована: Янв. 25, 2022

Язык: Английский

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Alternating Current Electrolysis as Efficient Tool for the Direct Electrochemical Oxidation of Hydroxamic Acids for Acyl Nitroso Diels–Alder Reactions

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(37), С. 20313 - 20317

Опубликована: Июль 7, 2021

The acyl nitroso Diels-Alder reaction of 1,3-dienes with electrochemically oxidised hydroxamic acids is described. By using alternating current electrolysis, their typical electro-induced decomposition could be suppressed in favour the 1,2-oxazine cycloaddition products. was optimised Design Experiments (DoE) and a sensitivity test conducted. A mixture triethylamine/hexafluoroisopropanol served as supporting electrolyte dichloromethane, thus giving products high purity after evaporation volatiles without further purification. conditions were applied to various acids, up 96 % isolated yield.

Язык: Английский

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Electrochemical Generation and Use in Organic Synthesis of C‐, O‐, and N‐Centered Radicals

The Chemical Record, Год журнала: 2021, Номер 21(9), С. 2538 - 2573

Опубликована: Май 28, 2021

Abstract During the last decade several research groups have been developing electrochemical procedures to access highly functionalized organic molecules. Among most exciting advances, possibility of using free radical chemistry has attracted attention important synthetic groups. Nowadays, strategies based on these species with a purpose are published continuously in scientific journals, increasing alternatives for laboratories. Free radicals can be obtained reactions; thus, this review reassembles decade's (2010–2020) efforts electrosynthetic community generate and take advantage C ‐, O N ‐centered radicals’ reactivity. The reactions that occur, as well proposed mechanism, discussed, trying give clear information about used conditions reactivity reactive intermediate species.

Язык: Английский

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Dehydrogenative Azolation of Arenes in a Microflow Electrochemical Reactor

The Journal of Organic Chemistry, Год журнала: 2021, Номер 86(22), С. 16195 - 16203

Опубликована: Авг. 30, 2021

The electrochemical synthesis of aryl azoles was performed for the first time in a microflow reactor. reaction relies on anodic oxidation arene partners making these substrates susceptible C–H functionalization with azoles, thus requiring no homogeneous transition-metal-based catalysts. synthetic protocol benefits from implementation setup, leading to shorter residence times (10 min), compared previously reported batch systems. Various azolated compounds (22 examples) are obtained good excellent yields.

Язык: Английский

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Enzyme immobilization: polymer–solvent–enzyme compatibility

Molecular Systems Design & Engineering, Год журнала: 2022, Номер 7(11), С. 1385 - 1414

Опубликована: Янв. 1, 2022

Immobilization improves enzyme stability, allows easy separation from reaction mixtures, and enables repeatable use over prolonged periods, especially in systems requiring continuous chemical reactions.

Язык: Английский

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An approach for the synthesis of 2-aryl-3-sulfonyl substituted quinolines through an electrochemical cascade annulation pathway

Green Chemistry, Год журнала: 2022, Номер 24(11), С. 4425 - 4431

Опубликована: Янв. 1, 2022

An electrochemical protocol for the synthesis of 2,3-disubstituted quinolines by reacting benzoxazinones with arylsulfonyl hydrazides was established under simple and mild conditions (room temperature an undivided cell).

Язык: Английский

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Electrochemically-promoted synthesis of benzo[b]thiophene-1,1-dioxides via strained quaternary spirocyclization

Chemical Science, Год журнала: 2022, Номер 13(34), С. 9940 - 9946

Опубликована: Янв. 1, 2022

We report an approach for the synthesis of benzothiophene motifs under electrochemical conditions by reaction sulfonhydrazides with internal alkynes. Upon formation a quaternary spirocyclization intermediate selective ipso-addition instead ortho-attack, S-migration process was rationalized to lead products. Computational studies revealed selectivity and compatibility drug molecules showcased potential application protocols.

Язык: Английский

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Regiodivergent C–N Coupling of Quinazolinones Controlled by the Dipole Moments of Tautomers

Organic Letters, Год журнала: 2022, Номер 24(17), С. 3144 - 3148

Опубликована: Апрель 21, 2022

Herein, we report that the dipole moments of tautomers can be controlling factor for regiodivergent synthesis either 14H-quinazolino[3,2-f]phenanthridin-14-ones or 6H-quinazolino[1,2-f]phenanthridin-6-ones, selectively, from unmasked 2-([1,1′-biphenyl]-2-yl)quinazolin-4(3H)-one. An intramolecular C(sp2)–NH coupling reaction mediated by PhI(OCOOCF3)2 could lead to two different regioisomers selectively at temperatures when dielectric constants solvents like hexafluoroisopropanol and trifluoroacetic acid matched with tautomer's moments.

Язык: Английский

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Electrochemical Dearomative Spirocyclization of N-Acyl Thiophene-2-sulfonamides

Organic Letters, Год журнала: 2022, Номер 24(34), С. 6321 - 6325

Опубликована: Авг. 22, 2022

The Friedel–Crafts type alkylation of C2-tethered thiophenes has been reported to be nonregioselective. Taking advantage the highly regioselective 5-exo-trig spirocyclization an electrochemically generated amidyl radical, we have unraveled electrochemical dearomative N-acyl thiophene-2-sulfonamides. Various nucleophilic agents, including carboxylates, alcohols, and fluoride, are readily incorporated afford remotely functionalized spirocyclic dihydrothiophenes, their novel scaffolds shown exhibit promising antitumor activities.

Язык: Английский

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