ChemInform Abstract: HIGH SITE-SELECTIVITY IN THE CHLORINATION OF ELECTRON-RICH AROMATIC COMPOUNDS BY N-CHLORAMMONIUM SALTS

1983 ◽  
Vol 14 (45) ◽  
Author(s):  
J. R. L. SMITH ◽  
L. C. MCKEER
Keyword(s):  
Aromatic Compounds ◽  
Site Selectivity ◽  
High Site

Caged iridium catalyst for hydrosilylation of alkynes with high site selectivity

ChemCatChem ◽  
2022 ◽  
Author(s):  
Qiaosheng Li ◽  
Defa Gu ◽  
Dongdong Yu ◽  
Yuzhou Liu
Keyword(s):  
Iridium Catalyst ◽  
Site Selectivity ◽  
High Site

Free-radical anti-Markovnikov hydroalkylation of unactivated alkenes with simple alkanes

2018 ◽  
Vol 20 (15) ◽  
pp. 3432-3435 ◽  
Author(s):  
Yunfei Tian ◽  
Anbo Ling ◽  
Ren Fang ◽  
Ren Xiang Tan ◽  
Zhong-Quan Liu
Keyword(s):  
Free Radical ◽  
Functional Group ◽  
Bond Cleavage ◽  
Site Selectivity ◽  
High Site

A Cu(ii)-mediated radical anti-Markovnikov hydroalkylation of unactivated alkenes with simple alkanes via selective C(sp3)–H bond cleavage was achieved. This reaction features high site-selectivity, diverse functional group tolerance, and scalability.

Palladium-catalyzed site-selective arylation of aliphatic ketones enabled by a transient ligand

2018 ◽  
Vol 54 (22) ◽  
pp. 2759-2762 ◽  
Author(s):  
Lei Pan ◽  
Ke Yang ◽  
Guigen Li ◽  
Haibo Ge
Keyword(s):  
Functional Group ◽  
Direct Arylation ◽  
Aliphatic Ketones ◽  
Site Selectivity ◽  
Palladium Catalyzed ◽  
High Site ◽  
Site Selective

A direct arylation of C–H bonds of ketones enabled by a cheap and commercially available transient ligand with high site-selectivity and functional group compatibility is reported.

scholarly journals Site-Selective Alkoxylation of Benzylic C–H Bonds via Photoredox Catalysis

2019 ◽  
Author(s):  
Byung Joo Lee ◽  
kimberly deglopper ◽  
Tehshik Yoon
Keyword(s):  
Late Stage ◽  
Functional Group ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Site Selectivity ◽  
Wide Range ◽  
High Site ◽  
Alkoxy Groups ◽  
Site Selective ◽  
Mediated Oxidation

<div> <div> <div> <p>There are relatively few methods that accom- plish the selective alkoxylation of sp3-hybridized C–H bonds, particularly in comparison to the numerous analogous strate- gies for C–N and C–C bond formation. We report a photo- catalytic protocol for the functionalization of benzylic C–H bonds with a wide range of readily available oxygen nucleo- philes. Our strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C–O bonds with high site selectivity, chemoselectivity, and functional group tolerance. This method enables the late- stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential appli- cations in synthesis and medicinal chemistry. </p> </div> </div> </div>

Mild, Efficient, and Regioselective Synthesis of Diiodophenyl­boronic Acid Derivatives via Metal–Iodine Exchange of 5-Substituted 1,2,3-Triiodoarenes

Synthesis ◽  
2017 ◽  
Vol 50 (02) ◽  
pp. 384-390 ◽  
Author(s):  
Raed Al-Zoubi ◽  
Abdellatif Ibdah ◽  
Walid Al-Jammal ◽  
Mazhar Al-Zoubi ◽  
Ahmad Almasalma ◽  
...  
Keyword(s):  
Micrococcus Luteus ◽  
Fungal Strain ◽  
Dilution Method ◽  
Antibacterial And Antifungal Activity ◽  
Site Selectivity ◽  
High Site ◽  
One Step ◽  
Antibacterial And Antifungal ◽  
Diffusion Assay

Unique 2,6-diiodophenylboronic acid and 2,3-diiodophenylboronic acid derivatives have been synthesized via regioselective metal–iodine exchange (MIE) of 5-substituted 1,2,3-triiodoarenes. The regio­selectivity of the reaction per se is remarkably controlled by the nature of the C5 substituent providing the desired diiodophenylboronic acids in moderate to good yields and with high site selectivity. The diiodophenylboronic acids were then examined for in vitro antimicrobial activity against four strains of bacteria Micrococcus luteus (ATCC 9341), Bacillus cereus (ATCC 11778), Escherichia coli (ATCC 25922), and Serratia marcescens (ATCC 27117) and one fungal strain Candida albicans using well diffusion assay and dilution method. It indicated that 5-fluoro-2,3-diiodophenylboronic acid possesses the most potent antibacterial and antifungal activity with MIC of 2.6 mg/mL for M. luteus and C. albicans. This report discloses a one-step protocol to access hitherto unknowns 2,6-diiodophenylboronic acid and 2,3-diiodophenylboronic acid derivatives that is scalable, good in scope, no chromatography is needed, and these compounds are difficult to prepare by other means.

scholarly journals Site-Selective Alkoxylation of Benzylic C–H Bonds via Photoredox Catalysis

2019 ◽  
Author(s):  
Byung Joo Lee ◽  
kimberly deglopper ◽  
Tehshik Yoon
Keyword(s):  
Late Stage ◽  
Functional Group ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Site Selectivity ◽  
Wide Range ◽  
High Site ◽  
Alkoxy Groups ◽  
Site Selective ◽  
Mediated Oxidation

<div> <div> <div> <p>There are relatively few methods that accom- plish the selective alkoxylation of sp3-hybridized C–H bonds, particularly in comparison to the numerous analogous strate- gies for C–N and C–C bond formation. We report a photo- catalytic protocol for the functionalization of benzylic C–H bonds with a wide range of readily available oxygen nucleo- philes. Our strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C–O bonds with high site selectivity, chemoselectivity, and functional group tolerance. This method enables the late- stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential appli- cations in synthesis and medicinal chemistry. </p> </div> </div> </div>

scholarly journals Site-Selective Alkoxylation of Benzylic C–H Bonds via Photoredox Catalysis

2019 ◽  
Author(s):  
Byung Joo Lee ◽  
kimberly deglopper ◽  
Tehshik Yoon
Keyword(s):  
Late Stage ◽  
Functional Group ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Site Selectivity ◽  
Wide Range ◽  
High Site ◽  
Alkoxy Groups ◽  
Site Selective ◽  
Mediated Oxidation

<div> <div> <div> <p>There are relatively few methods that accom- plish the selective alkoxylation of sp3-hybridized C–H bonds, particularly in comparison to the numerous analogous strate- gies for C–N and C–C bond formation. We report a photo- catalytic protocol for the functionalization of benzylic C–H bonds with a wide range of readily available oxygen nucleo- philes. Our strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C–O bonds with high site selectivity, chemoselectivity, and functional group tolerance. This method enables the late- stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential appli- cations in synthesis and medicinal chemistry. </p> </div> </div> </div>

Synthese und [4+2]-Cycloadditionen von 4a, 8a-Methanophthalazin, das erste Propellan mit einem elektronenreichen und einem elektronenarmen 4π-Diensystem/Synthesis and [4+2] Cycloaddition Reactions of 4a, 8a-Methanophthalazine, the First Propellane with an Electronrich and an Electrondeficient 4π-Diene System

1996 ◽  
Vol 51 (3) ◽  
pp. 348-358 ◽  
Author(s):  
Jörg Laue ◽  
Gunther Seitz ◽  
Hans Waßmuth
Keyword(s):  
Diels Alder ◽  
Azo Compounds ◽  
High Yield ◽  
The Novel ◽  
Inverse Electron Demand ◽  
Site Selectivity ◽  
Diene System ◽  
High Site ◽  
The One ◽  
Electron Demand

Abstract Cyclopropabenzene 3 reacts with 3,6-bis(trifluoro)-1,2,4,5-tetrazine 4 to afford in high yield the 4a,8a-methanophthalazine 6, the first propellane, containing an electron rich cyclohexadiene system on the one hand and an electron deficient diazadiene system on the other hand. According to the principle of Diels-Alder reactions with inverse electron demand, electron rich dienophiles like ketene acetals, enamines or dimethyl hydrazones react predominantly with the diazadiene system to yield the azo-bridged cycoadducts of type 19 and/or the tricyclic tetrahydropyridazines like 20. In the same fashion several more or less angle strained cycloalkenes cycloadd to the diazadiene of the propellane 6 to give the novel polycyclic azo compounds 34, 36, 38,40, 42 and 44 with exo-configuration of the annulated cycloalkanes. Attack apparently occurs from less hindered face anti to the methano bridge of 6 with high stereo-and site-selectivity. As anticipated the electron deficient dienophiles 1,2,4-triazoline-3,5-dione 45 and the benzoquinone 46 add with different site selectiviy to 6 furnishing the polycyclic pyridazines 47 and 48 resp. again by exclusive anti attack. Treatment of 6 with both an electron rich and an electron deficient dienophile like 49 and 45 resp. affords the heptacyclic anti-anti-bis adduct 51 with analogously high site-and stereoselectivity.

scholarly journals Biomimetic caged platinum catalyst for hydrosilylation reaction with high site selectivity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ganghuo Pan ◽  
Chunhua Hu ◽  
Song Hong ◽  
Huaping Li ◽  
Dongdong Yu ◽  
...  
Keyword(s):  
Active Site ◽  
Active Sites ◽  
Platinum Catalyst ◽  
Highly Active ◽  
Biomimetic Catalyst ◽  
Formidable Challenge ◽  
Confining Effect ◽  
Site Selectivity ◽  
Catalytic Active Site ◽  
High Site

AbstractNatural enzymes exhibit unparalleled selectivity due to the microenvironment around the active sites, but how to design artificial catalysts to achieve similar performance is a formidable challenge for the catalysis community. Herein, we report that a less selective platinum catalyst becomes highly active and selective for industrially relevant hydrosilylation of a broad range of substrates when a porous cage ligand is used for confinement around the catalytic active site. The catalyst is more than ten times more active than Karstedt’s catalyst while being recyclable. Properties such as size-selective catalysis and Michaelis-Menten kinetics support the proposed enzyme-like model. This biomimetic catalyst exhibits remarkable site-selectivity through the cage’s confining effect, which amplifies small steric differences into dramatic reactivity changes for similar functional groups within a molecule.

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