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Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
Isocyanurates with planar chirality: design, optical resolution, and isomerization
Hidetoshi Goto1, Masanao Sudoh, Keiko Kawamoto
1Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, Japan.
Chirality
|August 14, 2012
Summary
Novel isocyanurates were synthesized using a unique concept to create atropisomeric molecules. These compounds were successfully resolved and their isomerization barriers were measured, showing bulky groups and bridging inhibit rotation.
Area of Science:
- Organic Chemistry
- Stereochemistry
- Supramolecular Chemistry
Background:
- C(s)-symmetric, prochiral planar molecules possess enantiotopic faces.
- Differentiating these faces is key to creating chiral structures.
- Atropisomerism offers a route to stable molecular chirality.
Purpose of the Study:
- To design and synthesize novel atropisomeric isocyanurates.
- To investigate the structural and stereochemical properties of these compounds.
- To determine the rotational barriers and factors influencing isomerization.
Main Methods:
- Synthesis of isocyanurates (1-3) based on differentiating enantiotopic faces.
- Single-crystal X-ray diffraction for structural confirmation.
- Chiral high-performance liquid chromatography (HPLC) for optical resolution.
- Spectroscopic techniques (CD, UV-Vis, NMR, MS) for characterization.
- Determination of rotational barriers (ΔG‡) via isomerization studies.
Main Results:
- Isocyanurates 1 and 2(anti) exhibited planar chirality, confirmed by X-ray crystallography.
- Optical resolution of all synthesized isocyanurates (1-3) was achieved.
- Rotational barriers (ΔG‡) were measured: 27.2 kcal/mol (1), 27.6 kcal/mol (2), and 40.6 kcal/mol (3).
- Compound 3 displayed the highest rotational barrier, indicating significant isomerization inhibition.
Conclusions:
- A novel strategy for creating atropisomeric isocyanurates was successfully implemented.
- Bulky substituents and intramolecular bridging effectively inhibit isomerization.
- These findings contribute to the understanding and design of chiral molecules with restricted rotation.
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