A quantification scheme for non-covalent interactions in the enantio-controlling transition states in asymmetric catalysis

2018 ◽  
Vol 16 (31) ◽  
pp. 5643-5652 ◽  
Author(s):  
Santanu Malakar ◽  
S. V. Shree Sowndarya ◽  
Raghavan B. Sunoj
Keyword(s):  
Asymmetric Catalysis ◽  
Transition States ◽  
Non Covalent Interactions ◽  
Covalent Interactions

A simple quantification scheme for estimating the strength of non-covalent interactions in the enantio-controlling transition states is proposed.

scholarly journals Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

2020 ◽  
Vol 16 ◽  
pp. 1320-1334
Author(s):  
Carlos H Escalante ◽  
Eder I Martínez-Mora ◽  
Carlos Espinoza-Hicks ◽  
Alejandro A Camacho-Dávila ◽  
Fernando R Ramos-Morales ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Transition States ◽  
Diels Alder ◽  
Regioselective Synthesis ◽  
Heck Arylation ◽  
Oxidative Aromatization ◽  
Non Covalent Interactions ◽  
Covalent Interactions

A highly regio-, chemo- and stereoselective divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles is herein described, starting from 2-formylpyrrole and employing Diels–Alder and Heck arylation reactions. 3-(N-Benzyl-2-pyrrolyl)acrylates and 4-(pyrrol-2-yl)butenones underwent a highly endo-Diels–Alder cycloaddition with maleimides to furnish octahydropyrrolo[3,4-e]indoles, which served as precursors in the regioselective synthesis of aza-polycyclic skeletons via an intramolecular Heck arylation reaction. Through the latter reaction, the 3-(N-benzyl-2-pyrrolyl)acrylates give rise to 3-(pyrrolo[2,1-a]isoindol-3-yl)acrylates. A further oxidative aromatization of the polycyclic intermediates provides the corresponding polycyclic pyrrolo-isoindoles and isoindolo-pyrrolo-indoles. A theoretical study on the stereoselective Diels–Alder reactions, carried out by calculating the endo/exo transition states, revealed the assistance of non-covalent interactions in governing the endo stereocontrol.

scholarly journals Conformational Dynamics in Asymmetric Catalysis: Is Catalyst Flexibility a Design Element?

Synthesis ◽  
2019 ◽  
Vol 51 (05) ◽  
pp. 1021-1036 ◽  
Author(s):  
Jennifer Crawford ◽  
Matthew Sigman
Keyword(s):  
Hydrogen Bond ◽  
Asymmetric Catalysis ◽  
Conformational Dynamics ◽  
Short Review ◽  
Cinchona Alkaloids ◽  
Design Element ◽  
Peptide Catalysts ◽  
Enzymatic Systems ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Traditionally, highly selective low molecular weight catalysts have been designed to contain rigidifying structural elements. As a result, many proposed stereochemical models rely on steric repulsion for explaining the observed selectivity. Recently, as is the case for enzymatic systems, it has become apparent that some flexibility can be beneficial for imparting selectivity. Dynamic catalysts can reorganize to maximize attractive non-covalent interactions that stabilize the favored diastereomeric transition state, while minimizing repulsive non-covalent interactions for enhanced selectivity. This short review discusses catalyst conformational dynamics and how these effects have proven beneficial for a variety of catalyst classes, including tropos ligands, cinchona alkaloids, hydrogen-bond donating catalysts, and peptides.1 Introduction2 Tropos Ligands3 Cinchona Alkaloids4 Hydrogen-Bond Donating Catalysts5 Peptide Catalysts6 Conclusion

scholarly journals Parametrization of Non-covalent Interactions for Transition State Interrogation Applied to Asymmetric Catalysis

2017 ◽  
Vol 139 (20) ◽  
pp. 6803-6806 ◽  
Author(s):  
Manuel Orlandi ◽  
Jaime A. S. Coelho ◽  
Margaret J. Hilton ◽  
F. Dean Toste ◽  
Matthew S. Sigman
Keyword(s):  
Transition State ◽  
Asymmetric Catalysis ◽  
Non Covalent Interactions ◽  
Covalent Interactions

scholarly journals Improving Phase-Transfer Catalysis by Enhancing Non-Covalent Interactions

2020 ◽  
Author(s):  
Iñigo Iribarren ◽  
Cristina Trujillo
Keyword(s):  
Asymmetric Catalysis ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Intermolecular Hydrogen Bond ◽  
Pair Interaction ◽  
Unsaturated Ketone ◽  
Asymmetric Transformations ◽  
The Past ◽  
Non Covalent Interactions ◽  
Covalent Interactions

<p>A wide variety of asymmetric transformations catalysed by chiral catalysts have been developed for the synthesis of valuable organic compounds in the past several decades. Within asymmetric catalysis field, phase-transfer catalysis has been recognized as a powerful method for establishing useful procedures for organic synthesis. In the present study intermolecular interactions between a well-known alkaloid quinine-derived phase transfer catalyst and four different anions were characterised, analysing the competition between the pure ion-pair interaction and the intermolecular hydrogen bond established upon complexation. Finally, the energy profile corresponding to the enantioselective conjugate cyanation of a a,b-unsaturated ketone, under the presence of two different catalysts were performed.</p>

scholarly journals Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments

2015 ◽  
Author(s):  
Matteo Guidotti ◽  
Chiara Palumbo
Keyword(s):  
Asymmetric Catalysis ◽  
Organic Molecules ◽  
Optically Active ◽  
Fine Chemicals ◽  
Organic Transformations ◽  
Small Organic Molecules ◽  
Non Covalent Interactions ◽  
High Yields ◽  
Covalent Interactions ◽  
Covalent Activation

Abstract Organocatalysis, that is the use of small organic molecules to catalyze organic transformations, has been included among the most successful concepts in asymmetric catalysis, and it has been used for the enantioselective construction of C–C, C–N, C–O, C–S, C–P and C–halide bonds. Since the seminal works in early 2000, the scientific community has been paying an ever-growing attention to the use of organocatalysts for the synthesis, with high yields and remarkable stereoselectivities, of optically active fine chemicals of interest for the pharmaceutical industry. A brief overview is here presented about the two main classes of organocatalysis which are respectively characterized by covalent and non-covalent activation of the substrate. More detailed information about non-covalent interactions for organocatalysis are given. Finally, some successful examples of heterogenisation of organocatalysts are also discussed, in the view of a potential industrial exploitation.

scholarly journals Improving Phase-Transfer Catalysis by Enhancing Non-Covalent Interactions

2020 ◽  
Author(s):  
Iñigo Iribarren ◽  
Cristina Trujillo
Keyword(s):  
Asymmetric Catalysis ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Intermolecular Hydrogen Bond ◽  
Pair Interaction ◽  
Unsaturated Ketone ◽  
Asymmetric Transformations ◽  
The Past ◽  
Non Covalent Interactions ◽  
Covalent Interactions

<p>A wide variety of asymmetric transformations catalysed by chiral catalysts have been developed for the synthesis of valuable organic compounds in the past several decades. Within asymmetric catalysis field, phase-transfer catalysis has been recognized as a powerful method for establishing useful procedures for organic synthesis. In the present study intermolecular interactions between a well-known alkaloid quinine-derived phase transfer catalyst and four different anions were characterised, analysing the competition between the pure ion-pair interaction and the intermolecular hydrogen bond established upon complexation. Finally, the energy profile corresponding to the enantioselective conjugate cyanation of a a,b-unsaturated ketone, under the presence of two different catalysts were performed.</p>

NON COVALENT INTERACTIONS IN LARGE DIAMONDOID DIMERS IN THE GAS PHASE - A MICROWAVE STUDY

2017 ◽  
Author(s):  
Cristobal Perez ◽  
Melanie Schnell ◽  
Peter Schreiner ◽  
Norbert Mitzel ◽  
Yury Vishnevskiy ◽  
...  
Keyword(s):  
Gas Phase ◽  
Non Covalent Interactions ◽  
Covalent Interactions
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