Alkene-assisted cis-to-trans isomerization of non-conjugated polyunsaturated alkenes

2017 ◽  
Vol 46 (41) ◽  
pp. 14244-14250 ◽  
Author(s):  
A. V. Smarun ◽  
F. Duzhin ◽  
M. Petković ◽  
D. Vidović
Keyword(s):  
Kinetic Control ◽  
Trans Isomerization ◽  
Isomerization Catalyst

Complex [Cp*Ru(NCMe)3][PF6], 1a, has been identified as a cis-to-trans isomerization catalyst of various non-conjugated cis-polyalkenes under exceptional kinetic control as no alkene conjugation was observed.

Die Bildung eines Zirconium-substituierten Phosphor-Ylids durch sigmatrope Wasserstoffverschiebung / Formation o f a Zirconium Substituted Phosphorus Ylide by Sigmatropic Hydrogen Migration

1985 ◽  
Vol 40 (9) ◽  
pp. 1177-1180 ◽  
Author(s):  
Gerhard Erker ◽  
Peter Czisch ◽  
Richard Mynott
Keyword(s):  
Equilibrium Mixture ◽  
Kinetic Control ◽  
Conjugated Diene ◽  
Hydrogen Migration ◽  
Phosphorus Ylide ◽  
Trans Isomerization ◽  
Higher Temperature ◽  
Metallocene Complexes

σ-Crotylmetallocenyl substituted ylides (1) Cp2M(-CH2CH=CHCH3)(CHPPh3), M=Zr,Hf, are formed upon treatment of a mixture of (s-cis-) and (s-trans-η4-butadiene)metallocene complexes with the phosphorus ylide methylenetriphenylphosphorane (4). From the ( s-cis-/s-trans-butadiene) zirconocene equilibrium mixture (7/5) only the (s-cis-conjugated diene)metallocene isomer reacts with the ylide at -50 °C. Under kinetic control the fram-σ-crotylzirconocenyl-ylide (lb) is formed selectively; subsequent crotyl cis-trans-isomerization (1b⇆1b′) takes place at higher temperature (> -20 °C ). A mechanism including a concerted intramolecular homo-1,5- hydrogen migration step is proposed.

Trypsin entrapped within liposomes. Partition of a low-molecular-mass substrate as the main factor in kinetic control of hydrolysis

1991 ◽  
Vol 56 (3) ◽  
pp. 712-717 ◽  
Author(s):  
Jana Formelová ◽  
Albert Breier ◽  
Peter Gemeiner ◽  
Lubica Kurillová
Keyword(s):  
Molecular Mass ◽  
Egg Yolk ◽  
Kinetic Control ◽  
Hydrolysis Kinetics ◽  
Liposomal Membrane ◽  
Kinetics Of ◽  
Main Factor

Trypsin has been entrapped within liposomes prepared from egg yolk phospholipides by the method of controlled dialysis, and the hydrolysis kinetics of Nα-benzoyl-DL-arginine p-nitroaniline catalyzed by the liposome-entrapped trypsin has been studied by monitoring the flux of substrate and product across the liposomal membrane. The partitioning of the substrate and product between liposomal and extraliposomal environment has been found to represent the main factor in the kinetic control of the hydrolysis.

Cis–trans isomerization and optical laser writing in new heterocycle based azo-polyurethanes

2012 ◽  
Vol 34 (4) ◽  
pp. 724-728 ◽  
Author(s):  
Antonio Ambrosio ◽  
Fabio Borbone ◽  
Antonio Carella ◽  
Roberto Centore ◽  
Sandra Fusco ◽  
...  
Keyword(s):  
Laser Writing ◽  
Trans Isomerization ◽  
Optical Laser

Identifying and Evading Olefin Isomerization Catalyst Deactivation Pathways Resulting from Ion-Tunable Hemilability

ACS Catalysis ◽  
2020 ◽  
Vol 10 (21) ◽  
pp. 13019-13030
Author(s):  
Henry M. Dodge ◽  
Matthew R. Kita ◽  
Chun-Hsing Chen ◽  
Alexander J. M. Miller
Keyword(s):  
Catalyst Deactivation ◽  
Olefin Isomerization ◽  
Isomerization Catalyst

Solvent and viscosity effect on the kinetics of the thermal cis-trans isomerization of 3'-nitro-4-diethylaminoazobenzene

1989 ◽  
Vol 11 (3) ◽  
pp. 179-189 ◽  
Author(s):  
Bruno Marcandalli ◽  
Pier Luigi Beltrame ◽  
Ernestina Dubini-Paglia ◽  
Alberto Seves
Keyword(s):  
Viscosity Effect ◽  
Trans Isomerization ◽  
Kinetics Of

Kinetic Control of Length and Morphology of Segmented Polymeric Nanofibers in Microfluidic Chips

Langmuir ◽  
2020 ◽  
Vol 36 (44) ◽  
pp. 13364-13370
Author(s):  
Zhengping Tan ◽  
Zaiyan Hou ◽  
Ke Wang ◽  
Yuce Li ◽  
Lianbin Zhang ◽  
...  
Keyword(s):  
Kinetic Control ◽  
Microfluidic Chips ◽  
Polymeric Nanofibers

scholarly journals Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingfeng Yang ◽  
Hanze Ying ◽  
Zhixia Li ◽  
Jiang Wang ◽  
Yingying Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Molecular Structures ◽  
High Yield ◽  
Kinetic Control ◽  
High Concentration ◽  
Weak Association ◽  
Quantitative Synthesis ◽  
Thermodynamic Stabilization ◽  
Discrete Structures ◽  
Very High

AbstractMacrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.

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