Predictable Site-Selective Functionalization: Promoter Group Assisted para-Halogenation of N-Substituted (Hetero)Aromatics under Metal-Free Condition

2021 ◽  
Author(s):  
Shiv Shankar Gupta ◽  
Manisha . ◽  
Rakesh Kumar ◽  
Ankit Kumar Dhiman ◽  
Upendra Sharma
Keyword(s):  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Free Condition ◽  
Metal Free ◽  
Type Reaction ◽  
Selective Functionalization ◽  
Substitution Type ◽  
Site Selective

Herein, regioselective para-C-H halogenation of N-pyrimidyl (hetero)aromatics through SEAr (Electrophilic aromatic substitution) type reaction is disclosed. SEAr type reaction has been utilized for the C5-bromination of indolines (para-selective) with N-bromosuccinimide...

scholarly journals Site-selective remote C(sp3)–H heteroarylation of amides via organic photoredox catalysis

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Hui Chen ◽  
Wenjing Fan ◽  
Xiang-Ai Yuan ◽  
Shouyun Yu
Keyword(s):  
Hydrogen Atom ◽  
Room Temperature ◽  
Ph Value ◽  
Metal Free ◽  
Selective Functionalization ◽  
Site Selectivity ◽  
Hydrogen Atom Transfers ◽  
Site Selective ◽  
Neutral Conditions ◽  
Potential Complement

Abstract Radical translocation processes triggered by nitrogen-centered radicals (NCRs), such as 1,5-hydrogen atom transfers (1,5-HAT), demonstrated by the well-established Hofmann-Löffler-Freytag (HLF) reaction, provide an attractive approach for the controllable and selective functionalization of remote inert C(sp3)–H bonds. Here we report an amidyl radical-triggered site-selective remote C(sp3)–H heteroarylation of amides under organic photoredox conditions. This approach provides a mild and highly regioselective reaction affording remote C(sp3)–H heteroarylated amides at room temperature under transition-metal free, weakly basic, and redox-neutral conditions. Non-prefunctionalized heteroarenes, such as purines, thiazolopyridines, benzoxazole, benzothiazoles, benzothiophene, benzofuran, thiazoles and quinoxalines, can be alkylated directly. Sequential and orthogonal C–H functionalization of different heteroarenes by taking advantage pH value or polarity of radicals has also been achieved. DFT calculations explain and can predict the site-selectivity and reactivity of this reaction. This strategy expands the scope of the Minisci reaction and serves as its alternative and potential complement.

Metal-free C–H methylation and acetylation of heteroarenes with PEG-400

2020 ◽  
Vol 22 (11) ◽  
pp. 3506-3511
Author(s):  
Vishal Suresh Kudale ◽  
Jeh-Jeng Wang
Keyword(s):  
Metal Free ◽  
Peg 400 ◽  
Selective Functionalization ◽  
Efficient Route ◽  
Site Selective

Herein described a novel and an efficient route for the site selective functionalization of aza-heteroarenes using combination of PEG-400, O2 and TsOH·H2O.

scholarly journals Site-selective covalent functionalization at interior carbon atoms and on the rim of circumtrindene, a C36H12 open geodesic polyarene

2014 ◽  
Vol 10 ◽  
pp. 956-968 ◽  
Author(s):  
Hee Yeon Cho ◽  
Ronald B M Ansems ◽  
Lawrence T Scott
Keyword(s):  
Aromatic Hydrocarbons ◽  
Electrophilic Aromatic Substitution ◽  
Coupling Reactions ◽  
Computational Results ◽  
Aromatic Substitution ◽  
Covalent Functionalization ◽  
Polycyclic Aromatic ◽  
Site Selective ◽  
Geodesic Polyarenes ◽  
Derivatives Of

Circumtrindene (6, C36H12), one of the largest open geodesic polyarenes ever reported, exhibits fullerene-like reactivity at its interior carbon atoms, whereas its edge carbons react like those of planar polycyclic aromatic hydrocarbons (PAHs). The Bingel–Hirsch and Prato reactions – two traditional methods for fullerene functionalization – afford derivatives of circumtrindene with one of the interior 6:6 C=C bonds modified. On the other hand, functionalization on the rim of circumtrindene can be achieved by normal electrophilic aromatic substitution, the most common reaction of planar PAHs. This peripheral functionalization has been used to extend the π-system of the polyarene by subsequent coupling reactions and to probe the magnetic environment of the concave/convex space around the hydrocarbon bowl. For both classes of functionalization, computational results are reported to complement the experimental observations.

Electrophilic aromatic substitution over zeolites generates Wheland-type reaction intermediates

2017 ◽  
Vol 1 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Abhishek Dutta Chowdhury ◽  
Klaartje Houben ◽  
Gareth T. Whiting ◽  
Sang-Ho Chung ◽  
Marc Baldus ◽  
...  
Keyword(s):  
Electrophilic Aromatic Substitution ◽  
Reaction Intermediates ◽  
Aromatic Substitution ◽  
Type Reaction

scholarly journals Metal-free tandem Beckmann–electrophilic aromatic substitution cascade affording diaryl imines, ketones, amines, and quinazolines

2015 ◽  
Vol 56 (40) ◽  
pp. 5390-5392 ◽  
Author(s):  
Samuel R.S. Sarsah ◽  
Marlon R. Lutz ◽  
Kailyn Chichi Bobb ◽  
Daniel P. Becker
Keyword(s):  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Metal Free

para-Selective Cyanation of Arenes by H-Bonded Template

2019 ◽  
Author(s):  
Sandeep Pimparkar ◽  
Trisha Bhattacharya ◽  
Arun Maji ◽  
Argha Saha ◽  
Ramasamy Jayarajan ◽  
...  
Keyword(s):  
Selective Functionalization ◽  
Directing Group ◽  
Product Utility ◽  
Site Selective

The significance of site selective functionalization stands upon the superior selectivity, easy synthesis and diverse product utility. In this work we demonstrate the <i>para</i>-selective introduction of versatile nitrile moiety, enabled by detachable and reusable H-bonded auxiliary. The methodology holds its efficiency irrespective of substrate electronic bias. The conspicuous shift in the step energetics was probed by both experimental and computational mechanistic tools heralds the inception of <i>para</i>-deuteration. The synthetic impact of the methodology was highlighted with reusability of directing group and post synthetic modifications

para-Selective Cyanation of Arenes by H-Bonded Template

2019 ◽  
Author(s):  
Sandeep Pimparkar ◽  
Trisha Bhattacharya ◽  
Arun Maji ◽  
Argha Saha ◽  
Ramasamy Jayarajan ◽  
...  
Keyword(s):  
Selective Functionalization ◽  
Directing Group ◽  
Product Utility ◽  
Site Selective

The significance of site selective functionalization stands upon the superior selectivity, easy synthesis and diverse product utility. In this work we demonstrate the <i>para</i>-selective introduction of versatile nitrile moiety, enabled by detachable and reusable H-bonded auxiliary. The methodology holds its efficiency irrespective of substrate electronic bias. The conspicuous shift in the step energetics was probed by both experimental and computational mechanistic tools heralds the inception of <i>para</i>-deuteration. The synthetic impact of the methodology was highlighted with reusability of directing group and post synthetic modifications

Metal-free amino-controlled electrochemical intramolecular C–O and C–N couplings by site-selective activation of aryl C–N and C–O bonds

2021 ◽  
Author(s):  
Mu-Jia Luo ◽  
Gui-Fen Lv ◽  
Yang Li ◽  
Jin-Heng Li
Keyword(s):  
Free Amino ◽  
Selective Activation ◽  
Metal Free ◽  
Site Selective

Metal-free amino-assisted electrochemical intramolecular C–O or C–N couplings of amino-2-(2-aminoaryl)phenols are described.

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