Improving phase-transfer catalysis by enhancing non-covalent interactions.
Iñigo Iribarren1, Cristina Trujillo
1School of Chemistry, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland. trujillc@tcd.ie.
Physical Chemistry Chemical Physics : PCCP
|July 21, 2020
Summary
This study characterizes interactions between a quinine-derived catalyst and anions, analyzing ion-pair and hydrogen bond competition. It also explores the free-energy profile of enantioselective conjugate cyanation using theoretical methods.
Area of Science:
- Organic Chemistry
- Catalysis
- Computational Chemistry
Background:
- Asymmetric catalysis is crucial for synthesizing valuable organic compounds.
- Phase-transfer catalysis offers a powerful approach for organic synthesis.
- Chiral catalysts, particularly those derived from natural products like quinine, are key in asymmetric transformations.
Purpose of the Study:
- To characterize intermolecular interactions between a quinine-derived phase-transfer catalyst and various anions.
- To analyze the interplay between ion-pair interactions and hydrogen bonding in catalyst-anion complexation.
- To computationally investigate the enantioselective conjugate cyanation reaction mechanism and free-energy profile.
Main Methods:
- Characterization of intermolecular interactions using spectroscopic or computational methods.
- Analysis of competitive binding between ion-pair and hydrogen bond interactions.
- Theoretical calculation of the free-energy profile for enantioselective conjugate cyanation.
Main Results:
- Detailed characterization of intermolecular interactions involving a quinine-derived phase-transfer catalyst and different anions.
- Insights into the competition dynamics between pure ion-pair interactions and intermolecular hydrogen bonding.
- Computational elucidation of the reaction pathway and energy landscape for enantioselective conjugate cyanation.
Conclusions:
- Understanding catalyst-anion interactions is vital for optimizing phase-transfer catalysis.
- Theoretical studies provide valuable mechanistic insights into enantioselective reactions.
- This work contributes to the rational design of efficient chiral phase-transfer catalysts.
More Related Videos
10:52Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
Published on: April 12, 2019
13.2K
10:22In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions
Published on: June 16, 2014
18.6K
Related Concept Videos
01:13Introduction to Mechanisms of Enzyme Catalysis
10.2K
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes...
10.2K
01:14Phase II Conjugation Reactions: Overview
629
Conjugation, a key component of phase II biotransformation reactions, is a vital process in drug detoxification. It involves transferring endogenous substances like glucuronic acid, sulfate, and glycine to drugs or their metabolites formed in phase I reactions. These conjugation reactions, often catalyzed by specific enzymes, transform potentially harmful metabolites into inactive, water-soluble forms easily excreted in urine or bile. By enhancing polarity and eliminating pharmacological...
629
02:50Catalysis
29.8K
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
29.8K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.8K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.8K
01:07Catalytically Perfect Enzymes
4.8K
The theory of catalytically perfect enzymes was first proposed by W.J. Albery and J. R. Knowles in 1976. These enzymes catalyze biochemical reactions at high-speed. Their catalytic efficiency values range from 108-109 M-1s-1. These enzymes are also called 'diffusion-controlled' as the only rate-limiting step in the catalysis is that of the substrate diffusion into the active site. Examples include triose phosphate isomerase, fumarase, and superoxide dismutase.
Most enzymes...
Most enzymes...
4.8K
01:19Phase II Reactions: Miscellaneous Conjugation Reactions
263
Phase II biotransformations are detoxification mechanisms that conjugate xenobiotics with endogenous substances, neutralizing their toxicity.
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
263