Palladium-Catalyzed Site-Selective [5 + 1] Annulation of Aromatic Amides with Alkenes: Acceleration of β-Hydride Elimination by Maleic Anhydride from Palladacycle

ACS Catalysis ◽  
2022 ◽  
pp. 1595-1600
Author(s):  
Qiyuan He ◽  
Ken Yamazaki ◽  
Yusuke Ano ◽  
Naoto Chatani
Keyword(s):  
Maleic Anhydride ◽  
Palladium Catalyzed ◽  
Hydride Elimination ◽  
Site Selective

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 Palladium-catalyzed alkylation of unactivated olefins

2004 ◽  
Vol 76 (3) ◽  
pp. 671-678 ◽  
Author(s):  
Ross A. Widenhoefer
Keyword(s):  
Good Yield ◽  
Catalytic Amount ◽  
Outer Sphere ◽  
Deuterium Labeling ◽  
Carbon Nucleophiles ◽  
Keto Esters ◽  
Reactive Carbon ◽  
Aryl Ketones ◽  
Palladium Catalyzed ◽  
Hydride Elimination

The reaction of a 3-butenyl β-diketone with a catalytic amount of PdCl2(CH3CN)2 in dioxane at room temperature led to olefin hydroalkylation and formation of the corresponding 2-acylcyclohexanone in good yield as a single regioisomer. Deuterium-labeling experiments for the hydroalkylation of 7-octene-2,4-dione were in accord with a mechanism involving outer-sphere attack of the pendant enol on a palladium-complexed olefin to form a palladium cyclohexyl species, followed by palladium migration via iterative β-hydride elimination/addition and protonolysis from a palladium enolate complex. In comparison to a 3-butenyl β-diketone, reaction of a 4-pentenyl β-diketone with a catalytic amount of PdCl2(CH3CN)2 in the presence of CuCl2 led to oxidative alkylation and formation of the corresponding 2-acyl-3-methyl-2-cyclohexenone in good yield as a single isomer. Unactivated olefins tethered to less reactive carbon nucleophiles such as β-keto esters, α-aryl ketones, and even dialkyl ketones underwent palladium-catalyzed hydroalkylation in the presence of Me3SiCl or HCl to form the corresponding cyclohexanones in moderate-to-good yield with high regioselectivity.

ChemInform Abstract: Generation of Diverse 2-Pyrones via Palladium-Catalyzed Site-Selective Suzuki-Miyaura Couplings of 3-Bromo-4-tosyloxy-2-pyrone.

ChemInform ◽  
2012 ◽  
Vol 43 (8) ◽  
pp. no-no
Author(s):  
Xiaoli Lei ◽  
Liang Gao ◽  
Qiuping Ding ◽  
Yiyuan Peng ◽  
Jie Wu
Keyword(s):  
Palladium Catalyzed ◽  
Site Selective

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.

Palladium-Catalyzed Site-Selective C(sp3)–H Arylation of Phenylacetaldehydes

2019 ◽  
Vol 21 (17) ◽  
pp. 7084-7088 ◽  
Author(s):  
Bo-Bo Gou ◽  
Hang-Fan Liu ◽  
Jie Chen ◽  
Ling Zhou
Keyword(s):  
Palladium Catalyzed ◽  
Site Selective

ChemInform Abstract: Direct and Site-Selective Palladium-Catalyzed C-7 Acylation of Indolines with Aldehydes.

ChemInform ◽  
2015 ◽  
Vol 46 (26) ◽  
pp. no-no
Author(s):  
Youngmi Shin ◽  
Satyasheel Sharma ◽  
Neeraj Kumar Mishra ◽  
Sangil Han ◽  
Jihye Park ◽  
...  
Keyword(s):  
Palladium Catalyzed ◽  
Site Selective

Carbon Dioxide-Driven Palladium-Catalyzed C–H Activation of Amines: A Unified Approach for the Arylation of Aliphatic and Aromatic Primary and Secondary Amines

Synlett ◽  
2019 ◽  
Vol 30 (05) ◽  
pp. 519-524 ◽  
Author(s):  
Michael Young ◽  
Mohit Kapoor ◽  
Pratibha Chand-Thakuri ◽  
Justin Maxwell ◽  
Daniel Liu ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Bond Activation ◽  
Secondary Amines ◽  
Activation Process ◽  
Unified Approach ◽  
Benzylic Amines ◽  
Palladium Catalyzed ◽  
Group A ◽  
Directing Group ◽  
Site Selective

Amines are an important class of compounds in organic chemistry and serve as an important motif in various industries, including pharmaceuticals, agrochemicals, and biotechnology. Several methods have been developed for the C–H functionalization of amines using various directing groups, but functionalization of free amines remains a challenge. Here, we discuss our recently developed carbon dioxide driven highly site-selective γ-arylation of alkyl- and benzylic amines via a palladium-catalyzed C–H bond-activation process. By using carbon dioxide as an inexpensive, sustainable, and transient directing group, a wide variety of amines were arylated at either γ-sp3 or sp2 carbon–hydrogen bonds with high selectivity based on substrate and conditions. This newly developed strategy provides straightforward access to important scaffolds in organic and medicinal chemistry without the need for any expensive directing groups.1 Introduction2 C(sp3)–H Arylation of Aliphatic Amines3 C(sp2)–H Arylation of Benzylamines4 Mechanistic Questions5 Future Outlook

Sign in / Sign up

Export Citation Format

Share Document