Palladium-catalyzed directing group assisted and regioselectivity reversed cyclocarbonylation of arylallenes with 2-iodoanilines

2021 ◽  
Author(s):  
Jian-Shu Wang ◽  
Lingyun Yao ◽  
Jun Ying ◽  
Xiaoling Luo ◽  
Xiao-Feng Wu
Keyword(s):  
Dft Calculations ◽  
Palladium Catalyzed ◽  
Directing Group

A palladium-catalyzed regioselective cyclocarbonylation of N-(2-pyridyl)sulfonyl (N-SO2Py)-2-iodoanilines with allenes was developed. The regioselectivity of arylallenes was reversed. Control experiments and DFT calculations were performed to understand the reaction details.

Stereospecific, Palladium-catalyzed C(sp3)–H Alkenylation and Alkynylation of a Proline Derivative Enabled by 8-Aminoquinoline as a Directing Group

2020 ◽  
Author(s):  
Aleksandra Balliu ◽  
Aaltje Roelofje Femmigje Strijker ◽  
Michael Oschmann ◽  
Monireh Pourghasemi Lati ◽  
Oscar Verho
Keyword(s):  
Carboxylic Acid ◽  
Building Blocks ◽  
Wide Range ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
High Yields ◽  
Vinyl Iodides ◽  
Initial Results

<p>In this preprint, we present our initial results concerning a stereospecific Pd-catalyzed protocol for the C3 alkenylation and alkynylation of a proline derivative carrying the well utilized 8‑aminoquinoline directing group. Efficient C–H alkenylation was achieved with a wide range of vinyl iodides bearing different aliphatic, aromatic and heteroaromatic substituents, to furnish the corresponding C3 alkenylated products in good to high yields. In addition, we were able show that this protocol can also be used to install an alkynyl group into the pyrrolidine scaffold, when a TIPS-protected alkynyl bromide was used as the reaction partner. Furthermore, two different methods for the removal of the 8-aminoquinoline auxiliary are reported, which can enable access to both <i>cis</i>- and <i>trans</i>-configured carboxylic acid building blocks from the C–H alkenylation products.</p>

Temporary (PO) directing group enabled carbazole ortho arylation via palladium catalysis

2021 ◽  
Vol 57 (16) ◽  
pp. 2021-2024
Author(s):  
Zhi-Chao Qi ◽  
Qin-Xin Lou ◽  
Yuan Niu ◽  
Shang-Dong Yang
Keyword(s):  
Palladium Catalysis ◽  
Palladium Catalyzed ◽  
Directing Group

An efficient palladium-catalyzed, temporary P(O) directing group assisted C–H bond arylation of carbazoles was achieved, accompanied by the directing group being self-shed spontaneously.

scholarly journals A Palladium-Catalyzed Oxa-(4+4)-Cycloaddition Strategy Towards Oxazocine Scaffolds

Synlett ◽  
2021 ◽  
Author(s):  
Julian Garrec ◽  
Alexis Archambeau ◽  
Anaïs Scuiller ◽  
Xueyang Liu ◽  
Marie Cordier
Keyword(s):  
Dft Calculations ◽  
Palladium Catalyzed

AbstractA Pd-catalyzed oxa-(4+4)-cycloaddition between 1-azadienes and (2-hydroxymethyl)allyl carbonates is described. Aurone-derived azadienes furnished polycyclic 1,5-oxazocines in good yields. Interestingly, linear azadienes have also been involved and yielded monocyclic heterocycles with complete regioselectivity. DFT calculations were carried out to gain insight on this observation.

Intermolecular C–H Amidation of Alkenes with Carbon Monoxide and Azides via Tandem Palladium Catalysis

Synthesis ◽  
2021 ◽  
Author(s):  
Zheng-Yang Gu ◽  
Yang Wu ◽  
Feng Jin ◽  
Bao Xiaoguang ◽  
Ji-Bao Xia
Keyword(s):  
Carbon Monoxide ◽  
Palladium Catalysis ◽  
Computational Studies ◽  
Organic Azides ◽  
Reaction Proceeds ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
And Control

An atom- and step-economic intermolecular multi-component palladium-catalyzed C–H amidation of alkenes with carbon monoxide and organic azides has been developed for the synthesis of alkenyl amides. The reaction proceeds efficiently without an ortho-directing group on the alkene substrates. Nontoxic dinitrogen is generated as the sole by-product. Computational studies and control experiments have revealed that the reaction takes place via an unexpected mechanism by tandem palladium catalysis.

ChemInform Abstract: Palladium Catalyzed C-H Bond Acetoxylation: Isoxazolinyl as a Directing Group.

ChemInform ◽  
2016 ◽  
Vol 47 (44) ◽  
Author(s):  
Caiwei Geng ◽  
Minghui Jiang ◽  
Lifei Feng ◽  
Peng Jiao
Keyword(s):  
Palladium Catalyzed ◽  
Directing Group

scholarly journals Palladium-Catalyzed 2-(Neopentylsulfinyl)aniline Directed C-H Acetoxylation and Alkenylation of the Arylacetamides

2019 ◽  
Author(s):  
Maryia V. Barysevich ◽  
Marharyta V. Laktsevich-Iskryk ◽  
Anastasiya V. Krech ◽  
Vladimir N. Zhabinskii ◽  
Vladimir A. Khripach ◽  
...  
Keyword(s):  
One Pot ◽  
Palladium Catalyzed ◽  
Directing Group

A directing group that promotes very fast diacetoxylation of the arylacetamides is reported. The auxiliary also promotes alkenylation with vinyl ketones, which were generated in one-pot from the cyclopropanols.

scholarly journals Palladium-Catalysed C–F Alumination of Fluorobenzenes: Mechanistic Diversity and Origin of Selectivity

2020 ◽  
Author(s):  
Feriel Rekhroukh ◽  
Wenyi Chen ◽  
Ryan Brown ◽  
Andrew J. P. White ◽  
Mark Crimmin
Keyword(s):  
Dft Calculations ◽  
Bond Activation ◽  
Oxidative Addition ◽  
Fluorine Content ◽  
Model Potential ◽  
Heterometallic Complex ◽  
Experimental Support ◽  
Highly Active ◽  
Reaction Proceeds ◽  
Directing Group

A palladium pre-catalyst, [Pd(PCy<sub>3</sub>)<sub>2</sub>] is reported for the efficient and selective C–F alumination of fluorobenzenes with the aluminium(I) reagent [{(ArNCMe)<sub>2</sub>CH}Al] (<b>1</b>, Ar = 2,6-di-iso-propylphenyl). The catalytic protocol results in the transformation of sp<sup>2</sup> C–F bonds to sp<sup>2</sup> C–Al bonds and provides a route into reactive organoaluminium complexes (<b>2a-h</b>) from fluorocarbons. The catalyst is highly active. Reactions proceed within 5 minutes at 25 ºC (and at appreciable rates at even –50 ºC) and the scope includes low-fluorine-content substrates such as fluorobenzene, difluorobenzenes and trifluorobenzenes. The reaction proceeds with complete chemoselectivity (C–F vs C–H) and high regioselectivities ( >90% for C–F bonds adjacent to the most acidic C–H sites). The heterometallic complex [Pd(PCy<sub>3</sub>)(<b>1</b>)<sub>2</sub>] was shown to be catalytically competent. Catalytic C–F alumination proceeds with a KIE of 1.1–1.3. DFT calculations have been used to model potential mechanisms for C–F bond activation. These calculations suggest that two competing mechanisms may be in operation. Pathway 1 involves a ligand-assisted oxidative addition to [Pd(<b>1</b>)<sub>2</sub>] and leads directly to the product. Pathway 2 involves a stepwise C–H to C–F functionalisation mechanism in which the C–H bond is broken and reformed along the reaction coordinate, allowing it to act as a directing group for the adjacent C–F site. This second mechanism explains the experimentally observed regioselectivity. Experimental support for this C–H activation playing a key role in C–F alumination was obtained by employing [{(MesNCMe)<sub>2</sub>CH}AlH<sub>2</sub>] (<b>3</b>, Mes = 2,4,6-trimethylphenyl) as a reagent in place of 1. In this instance, the kinetic C–H alumination intermediate could be isolated. Under catalytic conditions this intermediate converts to the thermodynamic C–F alumination product.

scholarly journals Palladium-Catalyzed [3+2] Cycloaddition via Two-Fold 1,3-C(sp3)−H Activation

2020 ◽  
Author(s):  
Hojoon Park ◽  
jin-quan yu
Keyword(s):  
Functional Groups ◽  
Sulfonic Acid ◽  
Cycloaddition Reaction ◽  
Wide Range ◽  
Leaving Group ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
Overall Efficiency ◽  
Weak Coordination ◽  
Single Reaction

<div>Cycloaddition reactions provide an expeditious route to construct ring systems in a highly convergent and stereoselective manner. For a typical cycloaddition reaction to occur, however, the installation of multiple reactive functional groups (π-bonds, leaving group, etc.) are required within the substrates, compromising the overall efficiency or scope of the cycloaddition reaction. Here, we report a palladium-catalyzed [3+2] reaction that utilizes C(sp<sup>3</sup>)–H activation to generate the three-carbon unit for formal cycloaddition with maleimides. We implemented a strategy where the initial C(sp<sup>3</sup>)–H activation/olefin insertion would trigger a relayed, second remote C(sp<sup>3</sup>)–H activation to complete a formal [3+2] cycloaddition. The diastereoselectivity profile of this reaction resembles that of a typical pericyclic cycloaddition reaction in that the relationships between multiple stereocenters are exquisitely controlled in a single reaction. The key to success was the use of weakly coordinating amides as the directing group, as undesired Heck or alkylation pathways were preferred with other types of directing groups. The use of the pyridine-3-sulfonic acid ligands is critical to enable C(sp<sup>3</sup>)–H activation directed by this weak coordination. The method is compatible with a wide range of amide substrates, including lactams, which lead to novel spiro-bicyclic products. The [3+2] product is also shown to undergo a reductive desymmetrization process to access chiral cyclopentane bearing multiple stereocenters with excellent enantioselectivity.</div>

Palladium‐Catalyzed Selective o ‐Bromination of Mesoionic 1,3‐Diphenyltetrazolium‐5‐olate: Switching the Directing Group from Nitrogen to Oxygen

2021 ◽  
Vol 6 (47) ◽  
pp. 13414-13418
Author(s):  
Tsunehisa Hirashita ◽  
Harue Watanabe ◽  
Yuki Harada ◽  
Hideaki Kurabayashi ◽  
Yukinobu ◽  
...  
Keyword(s):  
Palladium Catalyzed ◽  
Directing Group
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