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Abstract An empirical model was developed to predict organic solvophobic effects usingN‐phenylimide molecular balances functionalized with non‐polar alkyl groups. Solution studies and X‐ray crystallography confirmed intramolecular alkyl‐alkyl interactions in theirfoldedconformers. The structural modularity of the balances allowed systematic variation of alkyl group lengths. Control balances were instrumental in isolating weak organic solvophobic effects by eliminating framework solvent‐solute effects. A19F NMR label enabled analysis across 46 deuterated and non‐deuterated solvent systems. Linear correlations were observed between organic solvophobic effects and solvent cohesive energy density (ced) as well as changes in solvent‐accessible surface areas (SASA). Using these empirical relationships, a model was constructed to predict organic solvophobic interaction energy per unit area for any organic solvent with knowncedvalues. The predicted interaction energies aligned with recent organic solvophobic measurements and literature values for the hydrophobic effect on non‐polar surfaces confirmed the model‘s accuracy and utility.
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Substituent and Solvent Effect Studies of N ‐Alkenylnitrone 4π Electrocyclizations**
Abstract The roles of substituent and solvent effects in promoting the 4π electrocyclization ofN‐alkenylnitrones to give azetidine nitrones have been investigated by experimental examination of relative rates, activation energies, and linear free energy relationships. These transformations are synthetically important because they favor the formation of a strained heterocyclic ring with imbedded functionality and stereochemical information for versatile derivatization. Mechanistic investigations, including Hammett studies, solvent‐dependent Eyring studies, and solvent isotope effects, provide insight into the steric and electronic factors that control these electrocyclizations and identify trends that can be used to advance this approach towards the rapid synthesis of complex azetidines.
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- Award ID(s):
- 1855833
- PAR ID:
- 10407256
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 29
- Issue:
- 30
- ISSN:
- 0947-6539
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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