Reactivity of Alkynes with M-C Bonds generated through C-H Activation DOI Creative Commons
Shyam Kumar Banjare, Pranav Shridhar Mahulkar, Tanmayee Nanda

et al.

Published: March 10, 2022

Transition metal-catalyzed C-H activation and functionalization with various coupling partners is a well-explored area of research. Among the used, alkynes occupy prominent position on account their varied reactivity. Due to low steric demand high degree unsaturation they effectively overlap metal d-orbitals form multiple bond-forming events giving rise complex skeletons that are otherwise challenging synthesize. This makes alkyne one most successful in terms number useful transformations. Remarkably, by changing reaction conditions transition-metals from 5d 3d, behaviors also change. Despite enormous explorations alkynes, there still lot more possible ways which can be made react M-C bonds generated through activation. Especially development new valent first-row catalysts, plenty scope for this chemistry evolve as explored areas research coming years. Therefore, review topic both timely synthetic chemists who working area. In review, we have highlighted diverse reactivity transition metals applications along some our thoughts future prospects.

Language: Английский

Weak‐Chelation Assisted Regioselective Indole C(4)‐Alkynylation via Six‐Membered Cobaltacycle Intermediate DOI

Sofaya Joshi,

Riya Dutta, Shyam Kumar Banjare

et al.

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(6), P. 1341 - 1347

Published: Jan. 13, 2024

Abstract Herein a regioselective indole C4‐alkynylation has been uncovered utilizing an earth‐abundant cobalt(III)‐catalyst. For this process, (bromoethynyl)benzene was used as alkynylating agent. Also, after screening various amide‐protected chelating groups we found dimethyl‐amide is optimal for the in‐situ generation of cobaltacycle intermediate. The six‐membered intermediate detected through high‐resolution mass spectrometry HRMS, which key conversion. Further, mechanistic studies were performed such KIE experiments, and reactions with radical scavengers, based on results plausible mechanism proposed. Moreover, to show application methodology, product oxidized diketone, monoketone, alkene, alkane further derivatized tricycle derivative, core structure many natural products.

Language: Английский

Citations

5
Diverse reactivity of alkynes in C–H activation reactions DOI
Shyam Kumar Banjare, Pranav Shridhar Mahulkar, Tanmayee Nanda

et al.

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(74), P. 10262 - 10289

Published: Jan. 1, 2022

The metal–carbon bond generated through C–H activation is a key organometallic intermediate, which could be further functionalized with various reacting partners. Among the coupling partners used in metal-catalysed activation, alkynes occupy prominent position on account of their varied reactivity.

Language: Английский

Citations

18
Intermolecular C–H Aminocyanation of Indoles via Copper–iodine Cocatalyzed Tandem C–N/C–C Bond Formation DOI
Wenhua Yu, Xiaoxiang Zhang, Chenrui Liu

et al.

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 87(18), P. 12424 - 12433

Published: Sept. 1, 2022

An efficient copper–iodine cocatalyzed intermolecular C–H aminocyanation of indoles with a broad substrate scope has been developed for the first time. This method enables highly step-economic access to 2-amino-3-cyanoindoles in moderate good yields and provides complementary strategy regioselective difunctionalization carbon═carbon double bonds interest organic synthesis related areas. Mechanistic studies suggest that these transformations are initiated by iodine-mediated C2–H amination azoles, followed copper-catalyzed C3–H cyanation ethyl cyanoformate.

Language: Английский

Citations

17
Expanding the Scope of Alkynes in C–H Activation: Weak Chelation-Assisted Cobalt-Catalyzed Synthesis of Indole C(4)-Acrylophenone via C–O Bond Cleavage of Propargylic Ethers DOI
Pranav Shridhar Mahulkar,

Sofaya Joshi,

Shyam Kumar Banjare

et al.

Organic Letters, Journal Year: 2024, Volume and Issue: 26(10), P. 2091 - 2096

Published: March 5, 2024

Herein, we report the facile synthesis of indole C(4)-acrylophenone using a C–H bond activation strategy. For this conversion, an unsymmetrical alkyne (phenylethynyl ether) in presence cobalt(III)-catalyst works efficiently. In process, gets oxidized situ generated water, which is key step for method, trifluoroethanol water source. The pivaloyl directing group chelates effectively to generate cobaltacycle intermediate, was detected through high-resolution mass spectrometry (HRMS). Also, formation bis(2,2,2-trifluoroethyl) ether has been confirmed and quantified 19F NMR. addition, applicability obtained product demonstrated by performing Nazarov cyclization conjugate addition α,β-unsaturated ketone moiety.

Language: Английский

Citations

3
Recent Advances in the High‐Valent Cobalt‐Catalyzed C−H Functionalization of N‐Heterocycles DOI
Devesh Chandra,

XXXXXXX Manisha,

Upendra Sharma

et al.

The Chemical Record, Journal Year: 2021, Volume and Issue: 22(3)

Published: Dec. 21, 2021

Abstract Direct functionalization of heterocycles using C−H activation widely relies on the precious metal complexes. In past decade, use earth abundant and inexpensive transition to functionalize has become an attractive alternate strategy. This concept is also interesting due unique reactivity pattern these metals. this context we other research groups have utilized high‐valent cobalt complexes as readily available catalyst for heterocycles. review, intend brief recent progress made in area catalyzed N ‐containing

Language: Английский

Citations

21
Directed C–H Functionalization of C3-Aldehyde, Ketone, and Acid/Ester-Substituted Free (NH) Indoles with Iodoarenes via a Palladium Catalyst System DOI Creative Commons
Yunus Taskesenligil, Murat Aslan,

Tuba Cogurcu

et al.

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 88(3), P. 1299 - 1318

Published: May 24, 2022

Pd(II)-catalyzed C-H arylations of free (NH) indoles including different carbonyl directing groups on C3-position with aryl iodides are demonstrated. Importantly, the reactions carried out using same catalyst system without any additional transient group (TDG). In this study, formyl as a gave C4-arylated versus C2-arylation. Using system, functionalization 3-acetylindoles provided domino C4-arylation/3,2-carbonyl migration products. This transformation involves unusual acetyl to C2-position following C4-arylation in one pot. Meanwhile, could be simply controlled and N-protected afforded products group. Functionalization indole-3-carboxylic acid (or methyl ester) present Pd(II)-catalyst resulted decarboxylation followed by formation C2-arylated indoles. Based control experiments literature, plausible mechanisms proposed. The synthetic utilities these acetylindole derivatives have also been Remarkably, acetylindoles allowed construction functionalized pityiacitrin (a natural product).

Language: Английский

Citations

16
Rhodium(iii)-catalyzed regioselective C(sp2)–H activation of indoles at the C4-position with iodonium ylides DOI
Fuhai Wu,

Lin Xiao,

Hui Xie

et al.

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 20(25), P. 5055 - 5059

Published: Jan. 1, 2022

Herein, we report a Rh( iii )-catalyzed C4-selective activation of indoles by using iodonium ylides as carbene precursors.

Language: Английский

Citations

13
Directing Group Guided Site-Selective Diversification of Indoles by Aziridine: Synthesis of β-Indolylethylamines DOI
Gulraız Ahmad,

Himangsu Sekhar Dutta,

Mohit Kumar

et al.

Organic Letters, Journal Year: 2022, Volume and Issue: 24(15), P. 2783 - 2787

Published: April 8, 2022

A palladium catalyzed directing group assisted cross-coupling of aliphatic aziridines with indole, indoline, tetrahydroquinoline, and aniline has been developed to furnish the corresponding β-arylethylamine derivatives. The substrate scope was very general, protocol also tolerated in presence various external additives. Control experiments suggested that C–H cleavage step is rate-determining step.

Language: Английский

Citations

9
Five-membered ring systems: pyrroles and benzo analogs DOI
Justin M. Lopchuk

Progress in heterocyclic chemistry, Journal Year: 2023, Volume and Issue: unknown, P. 155 - 207

Published: Jan. 1, 2023

Language: Английский

Citations

5
Uncovering the Reactivity of Cobalt‐Catalyst Towards Regioselective Hydroarylation of 1,6‐Diyne via Weak‐Chelation Assisted C−H Bond Activation DOI
Shyam Kumar Banjare,

Saista Afreen,

Pranav Shridhar Mahulkar

et al.

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 365(12), P. 1977 - 1982

Published: June 2, 2023

Abstract Herein, we report the reactivity of cobalt(III)‐catalyst towards hydroarylative functionalization 1,6‐diyne, which has never been explored before. The N ‐aryl lactam is prime substrate that undergoes sp 2 C−H bond activation. C−Co(III) formation occurs through weakly coordinating group. reaction mechanism reveals in‐situ a six‐membered cobaltacycle further with 1,6‐diyne. Also, radical quenching experiments suggest involvement ionic pathway for this conversion. In addition, hydrogen scrambling and kinetic isotope support proposed mechanism. A wide range electronically biased substrates reacting partners work well method in highly atom‐economical fashion.

Language: Английский

Citations

5