scholarly journals Mechanistic investigation of aziridine aldehyde-driven peptide macrocyclization: the imidoanhydride pathway

2015 ◽  
Vol 6 (10) ◽  
pp. 5446-5455 ◽  
Author(s):  
Serge Zaretsky ◽  
Jennifer L. Hickey ◽  
Joanne Tan ◽  
Dmitry Pichugin ◽  
Megan A. St. Denis ◽  
...  
Keyword(s):  
Multicomponent Reaction ◽  
Mechanistic Investigation ◽  
Aziridine Aldehyde ◽  
Aziridine Aldehydes ◽  
Amino Amides

Aziridine aldehydes participate in a multicomponent reaction with α-amino amides and isocyanides to generate reactive imidoanhydride intermediates.

Evolution of Metastable Structures in Bimetallic Catalysts from Microscopy and Machine-Learning Molecular Dynamics

2020 ◽  
Author(s):  
Jin Soo Lim ◽  
Jonathan Vandermause ◽  
Matthijs A. van Spronsen ◽  
Albert Musaelian ◽  
Christopher R. O’Connor ◽  
...  
Keyword(s):  
Machine Learning ◽  
Molecular Dynamics ◽  
Large Scale ◽  
Materials Science ◽  
Complete Characterization ◽  
Layer By Layer ◽  
Surface Restructuring ◽  
Metastable Structures ◽  
Mechanistic Investigation ◽  
Underlying Mechanisms

Restructuring of interface plays a crucial role in materials science and heterogeneous catalysis. Bimetallic systems, in particular, often adopt very different composition and morphology at surfaces compared to the bulk. For the first time, we reveal a detailed atomistic picture of the long-timescale restructuring of Pd deposited on Ag, using microscopy, spectroscopy, and novel simulation methods. Encapsulation of Pd by Ag always precedes layer-by-layer dissolution of Pd, resulting in significant Ag migration out of the surface and extensive vacancy pits. These metastable structures are of vital catalytic importance, as Ag-encapsulated Pd remains much more accessible to reactants than bulk-dissolved Pd. The underlying mechanisms are uncovered by performing fast and large-scale machine-learning molecular dynamics, followed by our newly developed method for complete characterization of atomic surface restructuring events. Our approach is broadly applicable to other multimetallic systems of interest and enables the previously impractical mechanistic investigation of restructuring dynamics.

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>

Mechanistic Investigation of Rh(I)-Catalyzed Asymmetric Suzuki-Miyaura Coupling with Racemic Allyl Halides

2019 ◽  
Author(s):  
Lucy van Dijk ◽  
Ruchuta Ardkhean ◽  
Mireia Sidera ◽  
Sedef Karabiyikoglu ◽  
Özlem Sari ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Experimental Studies ◽  
Mechanistic Investigation ◽  
Allyl Halides

A mechanism for Rh(I)-catalyzed asymmetric Suzuki-Miyaura coupling with racemic allyl halides is proposed based on a combination of experimental studies and quantum chemical calculations. <br>

Kinetic and mechanistic investigation of the sequential hydrogenation of phenylacetylene catalyzed by OsHCl(CO)(PR3)2 [PR3 = PMe-tert-Bu2 and P-i-Pr3]

1989 ◽  
Vol 111 (19) ◽  
pp. 7431-7437 ◽  
Author(s):  
Antida Andriollo ◽  
Miguel A. Esteruelas ◽  
Uwe Meyer ◽  
Luis A. Oro ◽  
Roberto A. Sanchez-Delgado ◽  
...  
Keyword(s):  
Mechanistic Investigation

scholarly journals Electrochemical multicomponent synthesis of 4-selanylpyrazoles under catalyst- and chemical-oxidant-free conditions

2021 ◽  
Author(s):  
Yan Wu ◽  
Jin-Yang Chen ◽  
Jing Ning ◽  
Xue Jiang ◽  
Jie Deng ◽  
...  
Keyword(s):  
Multicomponent Reaction ◽  
Raw Materials ◽  
Multicomponent Synthesis ◽  
Mild Conditions ◽  
Simple Protocol ◽  
High Yields

An electrochemical multicomponent reaction was established under catalyst-, chemical-oxidant-free and mild conditions, which provides an eco-friendly and simple protocol for constructing 4-selanylpyrazoles from easily available raw materials with high yields.

scholarly journals Synthesis, oligomerization and catalytic studies of a redox-active Ni4-cubane: a detailed mechanistic investigation

RSC Advances ◽  
2021 ◽  
Vol 11 (37) ◽  
pp. 22849-22858
Author(s):  
Saroj Kumar Kushvaha ◽  
Maria Francis ◽  
Jayasree Kumar ◽  
Ekta Nag ◽  
Prathap Ravichandran ◽  
...  
Keyword(s):  
Nickel Complex ◽  
Efficient Catalyst ◽  
Aromatic Heterocycles ◽  
Redox Active ◽  
Mechanistic Investigation

A robust tetrameric nickel complex [Ni4((Oal−)2L-Me)4(s)4] (s = solvent) with cubane-like Ni4O4 core topology identified as the efficient catalyst for the diastereoselective cyclopropanation of aromatic heterocycles.

KINETIC AND MECHANISTIC INVESTIGATION OF THE BACTERIAL LUCIFERASE REACTION

1991 ◽  
pp. 273-276
Author(s):  
Frank M. Raushel ◽  
Husam M. Abu-Soud ◽  
Leisha S. Mullins ◽  
Wilson A. Francisco ◽  
Thomas O. Baldwin
Keyword(s):  
Bacterial Luciferase ◽  
Mechanistic Investigation
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