Nickel catalyzed site selective C–H functionalization of α-aryl-thioamides

2018 ◽  
Vol 16 (35) ◽  
pp. 6405-6409 ◽  
Author(s):  
Debashruti Bandyopadhyay ◽  
Annaram Thirupathi ◽  
Nagsen Munjaji Dhage ◽  
Nirmala Mohanta ◽  
S. Peruncheralathan
Keyword(s):  
Bond Formation ◽  
Bond Functionalization ◽  
Site Selective ◽  
First Time ◽  
Functionalization Reaction

A nickel catalyzed C–H bond functionalization reaction has been used for the first time to study an intramolecular site-selective C–S bond formation of arenes.

Site-selective enzymatic C‒H amidation for synthesis of diverse lactams

Science ◽  
2019 ◽  
Vol 364 (6440) ◽  
pp. 575-578 ◽  
Author(s):  
Inha Cho ◽  
Zhi-Jun Jia ◽  
Frances H. Arnold
Keyword(s):  
Bond Formation ◽  
Enantiomeric Excess ◽  
Cytochrome P450 Enzymes ◽  
Preparative Scale ◽  
Bond Functionalization ◽  
Reactive Iron ◽  
Site Selectivity ◽  
Site Selective ◽  
And Control ◽  
Nitrogen Bond

A major challenge in carbon‒hydrogen (C‒H) bond functionalization is to have the catalyst control precisely where a reaction takes place. In this study, we report engineered cytochrome P450 enzymes that perform unprecedented enantioselective C‒H amidation reactions and control the site selectivity to divergently construct β-, γ-, and δ-lactams, completely overruling the inherent reactivities of the C‒H bonds. The enzymes, expressed in Escherichia coli cells, accomplish this abiological carbon‒nitrogen bond formation via reactive iron-bound carbonyl nitrenes generated from nature-inspired acyl-protected hydroxamate precursors. This transformation is exceptionally efficient (up to 1,020,000 total turnovers) and selective (up to 25:1 regioselectivity and 97%, please refer to compound 2v enantiomeric excess), and can be performed easily on preparative scale.

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

Theoretical and experimental studies of palladium-catalyzed site-selective C(sp3)−H bond functionalization enabled by transient ligands

2017 ◽  
Author(s):  
Haibo Ge ◽  
Lei Pan ◽  
Piaoping Tang ◽  
Ke Yang ◽  
Mian Wang ◽  
...  
Keyword(s):  
Bond Activation ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Bond Functionalization ◽  
Aliphatic Ketones ◽  
Site Selectivity ◽  
Mechanistic Investigation ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Site Selective

Transition metal-catalyzed selective C–H bond functionalization enabled by transient ligands has become an extremely attractive topic due to its economical and greener characteristics. However, catalytic pathways of this reaction process on unactivated sp<sup>3</sup> carbons of reactants have not been well studied yet. Herein, detailed mechanistic investigation on Pd-catalyzed C(sp<sup>3</sup>)–H bond activation with amino acids as transient ligands has been systematically conducted. The theoretical calculations showed that higher angle distortion of C(sp2)-H bond over C(sp3)-H bond and stronger nucleophilicity of benzylic anion over its aromatic counterpart, leading to higher reactivity of corresponding C(sp<sup>3</sup>)–H bonds; the angle strain of the directing rings of key intermediates determines the site-selectivity of aliphatic ketone substrates; replacement of glycine with β-alanine as the transient ligand can decrease the angle tension of the directing rings. Synthetic experiments have confirmed that β-alanine is indeed a more efficient transient ligand for arylation of β-secondary carbons of linear aliphatic ketones than its glycine counterpart.<br><br>

Recent Advances in C–Br Bond Formation

Synlett ◽  
2021 ◽  
Author(s):  
Ying-Yeung Yeung ◽  
Jonathan Wong
Keyword(s):  
Organic Synthesis ◽  
Aromatic Compounds ◽  
Bond Formation ◽  
Cross Coupling ◽  
Catalytic Site ◽  
Atom Transfer ◽  
Bond Forming ◽  
Recent Advances ◽  
Catalytic Asymmetric ◽  
Site Selective

AbstractOrganobromine compounds are extremely useful in organic synthesis. In this perspective, a focused discussion on some recent advancements in C–Br bond-forming reactions is presented.1 Introduction2 Selected Recent Advances2.1 Catalytic Asymmetric Bromopolycyclization of Olefinic Substrates2.2 Catalytic Asymmetric Intermolecular Bromination2.3 Some New Catalysts and Reagents for Bromination2.4 Catalytic Site-Selective Bromination of Aromatic Compounds2.5 sp3 C–H Bromination via Atom Transfer/Cross-Coupling3 Outlook

A Site‐Selective C−N Bond Formation of 2,4‐Dichloro‐5 H ‐pyrano[2,3‐ d ]pyrimidines and Amide

2021 ◽  
Vol 6 (43) ◽  
pp. 12032-12035
Author(s):  
Jinjing Qin ◽  
Zhenhua Li ◽  
Yingyan Cao ◽  
Yuanyuan Xie ◽  
Weike Su
Keyword(s):  
Bond Formation ◽  
A Site ◽  
Site Selective

Direct, Site‐Selective and Redox‐Neutral α‐C–H Bond Functionalization of Tetrahydrofurans via Quantum Dots Photocatalysis

2021 ◽  
Author(s):  
Li-Zhu Wu ◽  
Jia Qiao ◽  
Zi-Qi Song ◽  
Cheng Huang ◽  
Rui-Nan Ci ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Bond Functionalization ◽  
Site Selective

Highly Site-Selective Direct C−H Bond Functionalization of Unactivated Arenes with Propargyl α‑Aryl-α-diazoacetates via Scandium Catalysis

2021 ◽  
Author(s):  
Balu S. Navale ◽  
Debasish Laha ◽  
Subhrashis Banerjee ◽  
Kumar Vanka ◽  
Prof. Dr. Ramakrishna G. Bhat
Keyword(s):  
The Novel ◽  
Bond Functionalization ◽  
Site Selective

<p>Highly chemo- and regio-selective C–H bond functionalization of unactivated arenes with propargyl <i>α</i>-aryl-<i>α</i>-diazoacetates is developed using scandium catalysis. Variety of unactivated, mildly deactivated and electronically activated arenes are functionalized using this protocol. We have explored the novel combination of scandium triflate and propargyl <i>α</i>-aryl-<i>α</i>-diazoacetate as catalyst-reagent system for the effective C–H bond functionalization. The protocol avoids the use of expensive catalysts and practicality of the protocol has been demonstrated by the gram scale synthesis of very useful <i>α</i>-diarylacetates including antispasmodic drug-adephenine.</p>

Photoredox B–H Functionalization to Selective B–N(sp3) Coupling of nido-Carborane with Primary and Secondary Amines

2021 ◽  
Author(s):  
Hong Yan ◽  
Changsheng Lu ◽  
Ronghui Huang ◽  
Weijia Zhao ◽  
Shengwen Xu ◽  
...  
Keyword(s):  
Secondary Amines ◽  
Primary And Secondary Amines ◽  
Site Selective ◽  
First Time

Access to nido-carborane site-selective B–N(sp3) coupling by photoredox catalyzed B–H activation has been achieved for the first time, which leads to the synthesis of a series of nitrogen-containing nido-carboranes in...

Palladium-promoted sulfur atom migration on carboranes: facile B(4)−S bond formation from mononuclear Pd-B(4) complexes

2018 ◽  
Vol 90 (4) ◽  
pp. 607-616
Author(s):  
Yin-Ping Wang ◽  
Yue-Jian Lin ◽  
Guo-Xin Jin
Keyword(s):  
Sulfur Atom ◽  
Bond Formation ◽  
Reaction Process ◽  
One Pot ◽  
Leaving Group ◽  
Atom Migration ◽  
First Time

AbstractFor the first time, carborane complexes containing a B(4)–S bond were obtained directly by heating mononuclear Pd-B(4)-bound carborane complexes. A possible mechanism involved in sulfur atom migration is presented in which the leaving group, pyridine, benzyl isocyanide or PPh3, is demonstrated to be the trigger of the reaction process. In this work, efficient routes are developed through one-pot reactions to prepare B(4)-S carborane derivatives.

ChemInform Abstract: Metal-Free Oxidative C-C Bond Formation Through C-H Bond Functionalization

ChemInform ◽  
2015 ◽  
Vol 46 (50) ◽  
pp. no-no
Author(s):  
Rishikesh Narayan ◽  
Kiran Matcha ◽  
Andrey P. Antonchick
Keyword(s):  
Bond Formation ◽  
Bond Functionalization ◽  
Metal Free
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