Palladium-Catalyzed Asymmetric Allylic Amination Using Ferrocenyl Pyrazole Ligands:  Steric Control of η3-Allyl Configuration and Site-Selective Nucleophilic Attack

1996 ◽  
Vol 118 (5) ◽  
pp. 1031-1037 ◽  
Author(s):  
Antonio Togni ◽  
Urs Burckhardt ◽  
Volker Gramlich ◽  
Paul. S. Pregosin ◽  
Renzo Salzmann
Keyword(s):  
Nucleophilic Attack ◽  
Allylic Amination ◽  
Palladium Catalyzed ◽  
Site Selective ◽  
Pyrazole Ligands ◽  
Steric Control

A DFT investigation into the origin of regioselectivity in palladium-catalyzed allylic amination

2009 ◽  
Vol 87 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Marco Zimmer De Iuliis ◽  
Iain DG Watson ◽  
Andrei K Yudin ◽  
Robert H Morris
Keyword(s):  
Activation Barrier ◽  
Nucleophilic Attack ◽  
Ethylene Imine ◽  
Allylic Amination ◽  
Bond Forming ◽  
Allyl Complex ◽  
Phosphine Complexes ◽  
Palladium Catalyzed ◽  
Linear Olefin ◽  
Rule Out

The addition of amines or aziridines to prenylacetate is catalyzed by palladium phosphine complexes. The first-formed products have recently been shown to be the branched olefins R2NCMe2CH=CH2, R = alkyl, or R2 = 1,2-C6H10, for example. DFT calculations using the MPW1K functional were performed on reactions of the suspected intermediate η3-prenyl complex [Pd(η3-Me2CCHCH2)(PH3)2]+ with dimethylamine and ethylene imine. The activation barrier for the nucleophilic attack by the amine or the aziridine is calculated to be similar for either the sterically hindered site of the π-allyl ligand to produce the branched olefin complex or the unhindered site to give the linear olefin complex. Therefore, these calculations do not reveal the experimentally observed preference for attack. This observation, along with the experimental observation of lack of isomerization of the branched olefin product of the aziridine reactions, appears to rule out the intermediacy of a π-allyl complex [Pd(η3-Me2CCHCH2)L2]+, L = phosphine or L2 = diphosphine in the C–N bond-forming reaction.Key words: allyl palladium, amine, aziridine, DFT, mechanism, catalysis.

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>

Palladium-catalyzed C1-vinylation of β-naphthols with α-trifluoromethyl allyl carbonates: One-pot access to naphtho[2,1-b]furans

2021 ◽  
Author(s):  
Chiliveru Priyanka ◽  
Muppidi Subbarao ◽  
Nagender Punna
Keyword(s):  
Nucleophilic Attack ◽  
One Pot ◽  
Palladium Catalyzed

Highly regio- and stereoselective palladium-catalyzed C1-vinylation of β-naphthols (2) has been reported using easily accessible CF3-allyl carbonates (1). The regioselective nucleophilic -attack of CF3-π-allyl-Pd-intermediate is the key to furnish (Z)-CF3-vinylnaphthols...

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
Sign in / Sign up

Export Citation Format

Share Document