scholarly journals Coordinative Alignment of Chiral Molecules to Control over the Chirality Transfer in Spontaneous Resolution and Asymmetric Catalysis

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Zhengqiang Xia ◽  
Xu Jing ◽  
Cheng He ◽  
Xiaoge Wang ◽  
Chunying Duan
Keyword(s):  
Asymmetric Catalysis ◽  
Spontaneous Resolution ◽  
Chiral Molecules ◽  
Chirality Transfer

scholarly journals Computational Insight into the Rope-Skipping Isomerization of Diarylether Cyclophanes

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2127
Author(s):  
Thomas J. Summers ◽  
Hrishikesh Tupkar ◽  
Tyler M. Ozvat ◽  
Zoë Tregillus ◽  
Kenneth A. Miller ◽  
...  
Keyword(s):  
Asymmetric Catalysis ◽  
Room Temperature ◽  
Chemical Bonds ◽  
Chiral Molecules ◽  
Free Energies ◽  
Design And Synthesis ◽  
The Impact ◽  
Rope Skipping ◽  
Temperature Factors ◽  
Insight Into

The restricted rotation of chemical bonds may lead to the formation of stable, conformationally chiral molecules. While the asymmetry in chiral molecules is generally observed in the presence of one or more stereocenters, asymmetry exhibited by conformational chirality in compounds lacking stereocenters, called atropisomerism, depends on structural and temperature factors that are still not fully understood. This atropisomerism is observed in natural diarylether heptanoids where the length of the intramolecular tether constrains the compounds to isolable enantiomers at room temperature. In this work, we examine the impact tether length has on the activation free energies to isomerization of a diarylether cyclophane substructure with a tether ranging from 6 to 14 carbons. Racemization activation energies are observed to decay from 48 kcal/mol for a 7-carbon tether to 9.2 kcal/mol for a 14-carbon tether. Synthetic efforts to experimentally test these constraints are also presented. This work will likely guide the design and synthesis of novel asymmetric cyclophanes that will be of interest in the catalysis community given the importance of atropisomeric ligands in the field of asymmetric catalysis.

Chirality transfer based on dynamic covalent chemistry: from small chiral molecules to supramolecules

2019 ◽  
Vol 55 (66) ◽  
pp. 9861-9864 ◽  
Author(s):  
Panpan Sun ◽  
Shujing Ren ◽  
Aoli Wu ◽  
Na Sun ◽  
Lijuan Shi ◽  
...  
Keyword(s):  
Small Molecule ◽  
Chiral Molecules ◽  
Chirality Transfer ◽  
Dynamic Covalent Chemistry

Chirality transfer from small molecule to supramolecule was successfully achieved via regulation of dynamic covalent chemistry.

scholarly journals Carbohydrate-Based Chiral Iodoarene Catalysts: A Survey through the Development of an Improved Catalyst Design

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3883 ◽  
Author(s):  
Imrich ◽  
Biehler ◽  
Maichle-Mössmer ◽  
Ziegler
Keyword(s):  
Asymmetric Catalysis ◽  
Aromatic Compounds ◽  
Catalyst Design ◽  
Chiral Molecules ◽  
X Ray

Iodoarene catalysts can be applied in versatile reactions, for instance in the construction of complex chiral molecules via dearomatization of simple aromatic compounds. Recently, we reported the synthesis of the first carbohydrate-based chiral iodoarene catalysts and their application in asymmetric catalysis. Here we describe the synthesis of some new and improved catalysts. An account on how we got to the improved catalyst design, as well as the X-ray structure of one of the carbohydrate-based iodoarenes, is given.

Enantioselective organocatalytic approaches to active pharmaceutical ingredients – selected industrial examples

2019 ◽  
Vol 4 (8) ◽  
Author(s):  
Armando Carlone ◽  
Luca Bernardi
Keyword(s):  
Asymmetric Catalysis ◽  
Academic Research ◽  
Industrial Process ◽  
Added Value ◽  
Common Belief ◽  
Active Pharmaceutical Ingredients ◽  
Chiral Molecules ◽  
Metal Catalysis ◽  
Pharmaceutical Ingredients ◽  
Industrial Setting

Abstract Catalysis is, often, the preferred approach to access chiral molecules in enantioenriched form both in academia and in industry; nowadays, organocatalysis is recognised as the third pillar in asymmetric catalysis, along with bio- and metal-catalysis. Despite enormous advancements in academic research, there is a common belief that organocatalysis is not developed enough to be applicable in industry. In this review, we describe a selection of industrial routes and their R&D process for the manufacture of active pharmaceutical ingredients, highlighting how asymmetric organocatalysis brings added value to an industrial process. The thorough study of the steps, driven by economic stimuli, developed and improved chemistry that was, otherwise, believed to not be applicable in an industrial setting. The knowledge discussed in the reviewed papers will be an invaluable resource for the whole research community.

scholarly journals Chirality transfer in metal-catalysed intermolecular addition reactions involving allenes

2016 ◽  
Vol 3 (9) ◽  
pp. 1186-1204 ◽  
Author(s):  
José Miguel Alonso ◽  
María Teresa Quirós ◽  
María Paz Muñoz
Keyword(s):  
Asymmetric Catalysis ◽  
Addition Reactions ◽  
Chirality Transfer

This review covers chirality transfer in metal-catalysed intermolecular addition reactions involving allenes, including axial-to-central chirality transfer, asymmetric catalysis and racemization.

scholarly journals Enantioselective construction of six- and seven-membered triorgano-substituted silicon-stereogenic heterocycles

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shuyou Chen ◽  
Delong Mu ◽  
Pei-Lin Mai ◽  
Jie Ke ◽  
Yingzi Li ◽  
...  
Keyword(s):  
Asymmetric Catalysis ◽  
Chemical Space ◽  
Functional Materials ◽  
Chiral Molecules ◽  
Wide Range ◽  
Challenging Tasks ◽  
Organic Optoelectronic ◽  
Increasing Demand ◽  
Bright Blue Fluorescence ◽  
Bright Blue

AbstractThe exploitation of chirality at silicon in asymmetric catalysis is one of the most intriguing and challenging tasks in synthetic chemistry. In particular, construction of enantioenriched mediem-sized silicon-stereogenic heterocycles is highly attractive, given the increasing demand for the synthesis of novel functional-materials-oriented silicon-bridged compounds. Here, we report a rhodium-catalyzed enantioselective construction of six- and seven-membered triorgano-substituted silicon-stereogenic heterocycles. This process undergoes a direct dehydrogenative C−H silylation, giving access to a wide range of triorgano-substituted silicon-stereogenic heterocycles in good to excellent yields and enantioselectivities, that significantly enlarge the chemical space of the silicon-centered chiral molecules. Further elaboration of the chiral monohydrosilane product delivers various corresponding tetraorgano-substituted silicon-stereogenic heterocycles without the loss of enantiopurity. These silicon-bridged heterocycles exhibit bright blue fluorescence, which would have potential application prospects in organic optoelectronic materials.

Heterogeneous Interactions Promote Crystallization and Spontaneous Resolution of Chiral Molecules

2019 ◽  
Author(s):  
John Carpenter ◽  
Michael Gruenwald
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Crystallization Behavior ◽  
Amorphous Solids ◽  
Spontaneous Resolution ◽  
Low Energy ◽  
Coarse Grained ◽  
Chiral Molecules ◽  
Racemic Mixtures ◽  
Heterogeneous Interactions

Predicting the crystallization behavior of solutions of chiral molecules is a major challenge in the chemical sciences. In this paper, we use molecular dynamics computer simulations to study the crystallization of a family of coarse-grained models of chiral molecules with a broad range of molecular shapes and interactions. Our simulations reproduce the experimental crystallization behavior of real chiral molecules, including racemic and enantiopure crystals, as well as amorphous solids. Using efficient algorithms for the packing of shapes, we enumerate millions of low energy crystal structures for each model and analyze the thermodynamic landscape of polymorphs. In agreement with recent conjectures, our analysis shows that the ease of crystallization is largely determined by the number of competing polymorphs with low free energy. We find that this number, and hence crystallization outcomes, depend on molecular interactions in a simple way: Strongly heterogeneous interactions across molecules promote crystallization and favor the spontaneous resolution of racemic mixtures.

A Planar-Chiral Pillar[5]arene-Based Monophosphine Ligand with Induced Chirality at the Biaryl Axis

Synlett ◽  
2018 ◽  
Vol 29 (16) ◽  
pp. 2167-2170 ◽  
Author(s):  
Yuuya Nagata ◽  
Tomoki Ogoshi ◽  
Michinori Suginome ◽  
Yasuo Shimada ◽  
Tsuyoshi Nishikawa ◽  
...  
Keyword(s):  
Single Crystal ◽  
Diffraction Analysis ◽  
Asymmetric Catalysis ◽  
Cd Spectroscopy ◽  
Asymmetric Reactions ◽  
Side Chains ◽  
Chiral Ligand ◽  
X Ray Diffraction ◽  
Chirality Transfer ◽  
X Ray

A planar-chiral pillar[5]arene with cyclohexylmethoxy side chains and a pendant diphenylphosphine was prepared and used as a chiral ligand in asymmetric reactions. Chirality transfer from the planar-chiral pillar[5]arene scaffold to the chiral biaryl moiety was demonstrated by circular dichroism (CD) spectroscopy, single-crystal X-ray diffraction analysis, and asymmetric catalysis.

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