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.

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>

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>

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>

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>

Ru-Catalyzed highly site-selective C–H bond arylation of 9-(pyrimidin-2-yl)-9H-carbazole

RSC Advances ◽  
2016 ◽  
Vol 6 (59) ◽  
pp. 54431-54434 ◽  
Author(s):  
K. Harsha Vardhan Reddy ◽  
R. Uday Kumar ◽  
V. Prakash Reddy ◽  
G. Satish ◽  
Jagadeesh Babu Nanubolu ◽  
...  
Keyword(s):  
Functional Group ◽  
Boronic Acids ◽  
Site Selectivity ◽  
High Site ◽  
Site Selective

We describe an efficient ruthenium-catalyzed C–H bond ortho-arylation of 9-(pyrimidin-2-yl)-9H-carbazole using boronic acids. This methodology exhibits excellent and high site-selectivity, functional group tolerance and gave the desired product in moderate to good yields.

Non-directed highly para-selective C-H functionalization of TIPS-protected phenols promoted by a proton shuttle

2021 ◽  
Author(s):  
Jingyao Geng ◽  
Zhang Fang ◽  
Guangliang Tu ◽  
Yingsheng Zhao
Keyword(s):  
Bioactive Molecules ◽  
Protecting Group ◽  
Mechanism Study ◽  
Phenol Derivatives ◽  
Site Selectivity ◽  
Palladium Catalyzed ◽  
Direct Functionalization ◽  
Poor Site ◽  
Site Selective ◽  
First Time

Abstract Palladium-catalyzed non-directed C-H functionalization provides an efficient approach for direct functionalization of arenes, but it usually suffers from poor site selectivity, limiting its wide application. Herein, it is reported for the first time that the proton shuttle of 3,5-dimethyladamantane-1-carboxylic acid (1-DMAdCO2H) can affect the site selectivity during the C-H activation step in palladium-catalyzed non-directed C-H functionalization, leading to highly para-selective C-H olefination of TIPS-protected phenols. This transformation displayed good generality in realizing various other para-selective C-H functionalization reactions such as hydroxylation, halogenation, and allylation reactions. A wide variety of phenol derivatives including bioactive molecules of triclosan, thymol, and propofol, were compatible substrates, leading to the corresponding para-selective products in moderate to good yields. A preliminary mechanism study revealed that the spatial repulsion factor between proton shuttle and bulky protecting group resulted in the selective C-H activation at the less sterically hindered para-position. This new model non-directed para-selective C-H functionalization can provide a straightforward route for remote site-selective C-H activations.

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 chemo- and site-selective C–H acetoxylation and hydroxylation of oxobenzoxazine derivatives

2019 ◽  
Vol 17 (18) ◽  
pp. 4465-4469 ◽  
Author(s):  
Manickam Bakthadoss ◽  
Polu Vijay Kumar ◽  
Ravan Kumar ◽  
Vishal Agarwal
Keyword(s):  
Palladium Catalyst ◽  
Site Selectivity ◽  
Palladium Catalyzed ◽  
Site Selective

A new protocol for the acetoxylation and hydroxylation of oxobenzoxazine derivatives via an ortho-C–H functionalization strategy using a palladium catalyst has been developed with chemo- and site-selectivity.

scholarly journals Unraveling innate substrate control in site-selective palladium-catalyzed C–H heterocycle functionalization

2016 ◽  
Vol 7 (6) ◽  
pp. 3900-3909 ◽  
Author(s):  
Hwanho Choi ◽  
Minsik Min ◽  
Qian Peng ◽  
Dahye Kang ◽  
Robert S. Paton ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Direct Arylation ◽  
Palladium Catalyzed ◽  
Site Selective ◽  
Coupling Partner

Pd(ii)-catalyzed direct arylation of chromones and enaminones gives divergent site-selectivities. Computational and experimental studies reveal a switch in mechanism, from a C3-selective CMD mechanism to a C2-selective carbopalladation pathway. This model accounts for the opposite selectivities of enaminone and chromone, and also correctly predicts selectivities for the C–H functionalization of heteroaromatic substrates as a function of the coupling partner.

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