C(sp)–C(sp3) Bond Formation through Ligand- and Additive-Free CuO-Mediated Decarboxylative Direct Cross-Coupling of Coumarin-/Chromone-3-carboxylic Acids and Terminal Alkynes DOI
Anindita Bhowmick, Goutam Brahmachari

Organic Letters, Journal Year: 2023, Volume and Issue: 25(39), P. 7095 - 7099

Published: Sept. 22, 2023

A practical and efficient method for the synthesis of functionalized 4-(aryl-/heteroaryl-ethynyl)chroman-2-ones 2-(aryl-/heteroaryl-ethynyl)chroman-4-ones through copper-catalyzed decarboxylative direct cross-coupling coumarin-/chromone-3-carboxylic acids with terminal alkynes, leading to formation C(sp)–C(sp3) bonds, has been unearthed. Advantages this protocol include avoidance any ligands bases, a broad substrate scope, tolerance diverse functional groups, good excellent yields.

Language: Английский

Electrochemical Regioselective C(sp2)–H Selenylation and Sulfenylation of Substituted 2-Amino-1,4-naphthoquinones DOI
Pintu Karmakar, Indrajit Karmakar, D. R. PAL

et al.

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(2), P. 1049 - 1060

Published: Jan. 4, 2023

A straightforward and efficient electrochemical method for regioselective C(sp2)-H selenylation sulfenylation of substituted 2-amino-1,4-naphthoquinones has been unearthed. This oxidative cross-coupling reaction avoids using transition metal catalysts, oxidants, high temperatures. The other notable advantages this protocol are the tolerance diverse functional groups, mild conditions at ambient temperature, energy efficiency, good to excellent yields, short times (in minutes), gram-scale applicability, eco-friendliness.

Language: Английский

Citations

22
Visible-Light-Induced Regioselective C–H Sulfenylation of Pyrazolo[1,5-a]pyrimidines via Cross-Dehydrogenative Coupling DOI

Suvam Paul,

Sourav Das,

Tathagata Choudhuri

et al.

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(7), P. 4187 - 4198

Published: March 14, 2023

A visible-light-induced cross-dehydrogenative methodology has been developed for the regioselective sulfenylation of pyrazolo[1,5-a]pyrimidine derivatives. Rose bengal, blue LEDs, KI, K2S2O8, and DMSO are all essential this photocatalytic transformation. The protocol is applicable synthesis a library 3-(aryl/heteroaryl thio)pyrazolo[1,5-a]pyrimidine derivatives with broad functionalities. selectivity scalability have also demonstrated. Moreover, efficiency strategy pyrazoles, indole, imidazoheterocycles, 4-hydroxy coumarin proven. mechanistic investigation revealed radical-based mechanism formation diaryl disulfide as key intermediate coupling reaction.

Language: Английский

Citations

20
Rose‐Bengal‐Photocatalyzed Cross‐Dehydrogenative Coupling Reactions under Visible Light DOI

Divyani P. Patel,

Satish K. Singh

European Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 27(8)

Published: Jan. 19, 2024

Abstract Over the past few years, organic chemistry has used dye rose bengal‘s ability to absorb visible light. In present‐day research, innovation of environmentally friendly processes for carbon‐carbon/carbon‐heteroatoms (Nitrogen, Oxygen, Sulphur, and Phosphorus) bond formation great importance. The photocatalyzed cross‐dehydrogenative coupling (CDC) reactions using bengal (RB) is a promising technique creating carbon‐carbon/carbon‐heteroatom bonds directly from readily available compounds. Our review focuses on current advancement in that uses bond‐making synthesize various important molecules via CDC reactions.

Language: Английский

Citations

6
CH‐Functionalization of Heterocycles with the Formation of C−O, C−N, C−S/Se, and C−P Bonds by Intermolecular Addition of Heteroatom‐Centered Radicals DOI
Alexander S. Budnikov, Igor B. Krylov, Olga M. Mulina

et al.

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 365(11), P. 1714 - 1755

Published: April 12, 2023

Abstract In the last decade, free radicals have found a wide application in functionalization of unsaturated compounds, such as alkenes, alkynes, and arenes, via free‐radical addition to carbon‐carbon π‐bonds. these processes, intermolecular attack on aromatic substrates represents challenge due relatively high resistance π‐system reactions comparison alkene C=C bonds. The heterocycles is especially interesting diversity their structures chemical properties well importance for medicinal chemistry, agrochemistry, materials science. Addition C‐centered widely known Minisci‐type well‐reviewed. this paper, we summarized main achievements less explored group processes: by heteroatom‐centered (O‐, N‐, S‐/Se‐, P‐radicals) with emphasis papers published after 2010. Literature analysis revealed strong trend towards usage electrochemistry photoredox‐catalysis generation recent years. remaining fundamental problem field lack experimental support proposed mechanisms frequent existence several plausible reaction pathways. progress mechanistic studies can significantly improve prediction optimal conditions depending structure.

Language: Английский

Citations

14
Visible-light-induced organophotocatalytic and singlet oxygen-initiated domino construction of 1,4-dihydropyridines, C-3 functionalized spiro[indoline-3,4′-pyridines] and C-11 functionalized spiro[indeno-[1,2-b]quinoxaline-11,4′-pyridines] DOI
Biplob Borah, Mihir Patat, Vipin Singh

et al.

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(7), P. 1518 - 1530

Published: Jan. 1, 2023

A highly efficient pot, atom, and step economical method for the construction of pharmacologically potent structurally functionalized 1,4-dihydropyridines, quaternary centered C-3 spiro[indoline-3,4'-pyridines], C-11 spiro[indeno[1,2-b]quinoxaline-11,4'-pyridines] via rose bengal photoredox catalysis under blue LED irradiation in an aqueous medium at room temperature has been developed. The products were isolated excellent yields within a short reaction time variety functional groups transition metal- ligand-free energy-efficient conditions green solvent system with high mass efficiency process intensity, which are key advantages current work.

Language: Английский

Citations

13
Electrochemical and mechanochemical synthesis of dihydrofuro[3,2-c]chromenonesviaintramolecular Csp3–Hcross-dehydrogenative oxygenation within warfarin frameworks: an efficient and straightforward dual approach DOI
Indrajit Karmakar, Goutam Brahmachari

Green Chemistry, Journal Year: 2022, Volume and Issue: 24(7), P. 2825 - 2838

Published: Jan. 1, 2022

Electrochemical and mechanochemical synthesis of a new series functionalized dihydrofuro[3,2- c ]chromenones, involving intramolecular direct C sp3 –H cross -dehydrogenative oxygenation within the warfarin framework, has been accomplished.

Language: Английский

Citations

22
Visible-Light-Promoted Intramolecular C–O Bond Formation via Csp3–H Functionalization: A Straightforward Synthetic Route to Biorelevant Dihydrofuro[3,2-c]chromenone Derivatives DOI
Mullicka Mandal, Goutam Brahmachari

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 87(7), P. 4777 - 4787

Published: March 18, 2022

A photochemical method for the synthesis of functionalized dihydrofuro[3,2-c]chromenones via intramolecular Csp3-H cross-dehydrogenative oxygenation within a warfarin framework has been unearthed. Advantages this protocol include abundant sunlight or low-energy visible light as energy source, mild reaction conditions, and avoidance metal catalysts.

Language: Английский

Citations

21
Photochemical and electrochemical regioselective cross-dehydrogenative C(sp2)–H sulfenylation and selenylation of substituted benzo[a]phenazin-5-ols DOI

Nayana Nayek,

Pintu Karmakar, Mullicka Mandal

et al.

New Journal of Chemistry, Journal Year: 2022, Volume and Issue: 46(28), P. 13483 - 13497

Published: Jan. 1, 2022

The essence of photo- and electrochemistry: sulfenylation selenylation substituted benzo[ a ]phenazin-5-ols through cross-dehydrogenative C(sp 2 )–H functionalization.

Language: Английский

Citations

19
Visible‐Light‐Driven and Singlet Oxygen‐Mediated Synthesis of Biologically Relevant 2‐Hydroxyphenylated‐α‐Ketoamides Through Decarboxylative Amidation of 4‐Hydroxycoumarins DOI
Goutam Brahmachari, Indrajit Karmakar

Asian Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 11(3)

Published: Jan. 21, 2022

Abstract A new synthetic strategy for accessing a diverse series of 2‐hydroxyphenylated α‐ketoamides has been achieved based on visible light (white LED/direct sunlight)‐driven photocatalytic decarboxylative amidation 4‐hydroxycoumarins. Advantages this protocol include mild and energy‐efficient reaction conditions, the use dioxygen as reactant, avoidance metal catalysts. In addition, method offers pathway to install biologically potent hydroxy group at C‐2 position phenyl ring α‐ketoamide skeleton.

Language: Английский

Citations

17
Visible-light-induced C–H sulfenylation of quinoxalin-2(1H)-ones with disulfides by sustainable cerium catalysis DOI Creative Commons
Zhang Li-xi, Jingwen He, Pengfei Zhang

et al.

Green Synthesis and Catalysis, Journal Year: 2022, Volume and Issue: 4(3), P. 226 - 230

Published: April 12, 2022

Using visible light as energy to form free radicals has important synthetic value. A novel and efficient visible-light-mediated strategy been developed for the generation of thiobenzene through cerium-catalyzed activation disulfides. Through this photochemical reaction, various 3-sulfenylated quinoxalin-2(1H)-ones can be conveniently obtained in good yields with functional group tolerance. Our transformation provides an alternative that allows rapid access C3 sulfenylated a sustainable practical manner.

Language: Английский

Citations

17