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Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Racemization mechanism of axially chiral sym-tetraacetylethane: axial rotation vs. intramolecular proton migration
Mingyue Liu1, Bao Zhang1, Mingliang Chen1
1College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China. xianghaifeng@scu.edu.cn.
Abstract:
Despite a high rotational barrier from ortho-methyl groups, sym-tetraacetylethane-a distally axially chiral molecule with intramolecular hydrogen bonds-cannot be resolved by chiral HPLC. DFT reveals an unusual racemization pathway via hydrogen-bond-assisted intramolecular proton migration (barrier 1.33-3.00 kcal mol-1) that interconverts enantiomers without axial rotation or bond breaking, supported by NMR and UV-vis spectra.
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