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

Arene diversification through distal C(sp2)−H functionalization

Science ◽  
2021 ◽  
Vol 372 (6543) ◽  
pp. eabd5992
Author(s):  
Uttam Dutta ◽  
Sudip Maiti ◽  
Trisha Bhattacharya ◽  
Debabrata Maiti
Keyword(s):  
Transition Metal ◽  
Noncovalent Interactions ◽  
Catalyst Design ◽  
Selective Functionalization ◽  
Directing Group ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed ◽  
Site Selective

Transition metal–catalyzed aryl C−H activation is a powerful synthetic tool as it offers step and atom-economical routes to site-selective functionalization. Compared with proximal ortho-C−H activation, distal (meta- and/or para-) C−H activation remains more challenging due to the inaccessibility of these sites in the formation of energetically favorable organometallic pretransition states. Directing the catalyst toward the distal C−H bonds requires judicious template engineering and catalyst design, as well as prudent choice of ligands. This review aims to summarize the recent elegant discoveries exploiting directing group assistance, transient mediators or traceless directors, noncovalent interactions, and catalyst and/or ligand selection to control distal C−H activation.

scholarly journals Unsymmetrical Difunctionalization of Two Different C–H Bonds in One Pot Under Transition-Metal Catalysis

Synthesis ◽  
2018 ◽  
Vol 51 (01) ◽  
pp. 40-54 ◽  
Author(s):  
Masahito Murai ◽  
Kazuhiko Takai
Keyword(s):  
Transition Metal ◽  
Functional Groups ◽  
Aromatic Compounds ◽  
Transition Metal Catalysis ◽  
One Pot ◽  
Metal Catalysis ◽  
Selective Functionalization ◽  
Sequential Addition ◽  
Target Molecules ◽  
Directing Group

Recent advancements in unsymmetrical difunctionalization based on the substitution of two different C–H bonds in one-pot are described. Due to the difficulty of controlling reactivity and selectivity, multi-functionalization via substitution of several C–H bonds to install different functional groups has been limited until recently, in comparison with well-studied functionalization via sequential addition to unsaturated π-bonds. This difunctionalization protocol provides an efficient and rapid approach to a library of structurally complicated target molecules through the formation of multiple C–X bonds with high atom- and step-economy.1 Introduction2 ortho-Selective Functionalization of Two Different C–H Bonds Relative to the Directing Group2.1 Unsymmetrical Difunctionalization with the Introduction of Similar Functional Groups2.2 Unsymmetrical Difunctionalization with the Introduction of Different Functional Groups2.3 ortho-Selective Unsymmetrical Difunctionalization Promoted by Two Different Directing Groups Appearing During the Progress of the Reaction3 ortho/meta-Selective C–H Bond Difunctionalization Relative to the Directing Group4 Sequential Difunctionalization of Fused Aromatic Compounds and Heterocycles5 Summary and Outlook

scholarly journals A lesson for site-selective C–H functionalization on 2-pyridones: radical, organometallic, directing group and steric controls

2018 ◽  
Vol 9 (1) ◽  
pp. 22-32 ◽  
Author(s):  
Koji Hirano ◽  
Masahiro Miura
Keyword(s):  
Pharmaceutical Chemistry ◽  
Recent Advances ◽  
Directing Group ◽  
Site Selective

This minireview focuses on recent advances in site-selective C–H functionalization on 2-pyridone which is an important heterocyclic motif in medicinal and pharmaceutical chemistry.

scholarly journals Total Synthesis of Ellagitannins via Sequential Site-Selective Functionalization of Unprotected D-Glucose

2017 ◽  
Vol 65 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Hironori Takeuchi ◽  
Yoshihiro Ueda ◽  
Takumi Furuta ◽  
Takeo Kawabata
Keyword(s):  
Total Synthesis ◽  
Selective Functionalization ◽  
Site Selective

Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives

2018 ◽  
Vol 118 (23) ◽  
pp. 11457-11517 ◽  
Author(s):  
Victoria Dimakos ◽  
Mark S. Taylor
Keyword(s):  
Hydroxyl Groups ◽  
Selective Functionalization ◽  
Site Selective

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.

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