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Axial-Selective H/D Exchange of Glycine-Derived 1H-Benzo[e][1,4]diazepin-2(3H)-ones: Kinetic and Computational Studies of Enantiomerization
- Source :
- The Journal of Organic Chemistry. 75:6588-6594
- Publication Year :
- 2010
- Publisher :
- American Chemical Society (ACS), 2010.
-
Abstract
- Glycine-derived 1H-benzo[e][1,4]diazepin-2(3H)-ones (BZDs) 5d-g featuring C9- and N1- substitution exhibit enantiomerization barriers too high to be measured by (1)H NMR coalescence experiments. To address this problem, we found that room-temperature H/D exchange of these compounds is remarkably selective, affording only the axial-d(1) isotopomers. (1)H NMR spectroscopy was then employed to measure the rate of conformational inversion of these d(1)-compounds at elevated temperatures. These studies reveal the highest enantiomerization barriers (up to 28 kcal/mol) ever determined for a BZD. Density functional theory calculations match the experimental enantiomerization barriers within 1.2 kcal/mol.
Details
- ISSN :
- 15206904 and 00223263
- Volume :
- 75
- Database :
- OpenAIRE
- Journal :
- The Journal of Organic Chemistry
- Accession number :
- edsair.doi.dedup.....930daf745ed33b968afa1751a6ff25e6