Configurational 1H NMR study of optically active 7-(1-phenylethyl)-2-oxa-7-azabicyclo[3.2.0]heptan-6-one derivatives using Pirkle’s alcohols and a chiral shift reagent
✍ Scribed by Cirilo García-Martínez; Yoichi Taguchi; Akihiro Oishi; Kikuko Hayamizu
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 340 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0749-1581
No coin nor oath required. For personal study only.
✦ Synopsis
Four novel stereoisomers of 7-(1-phenylethyl)-2-oxa-7-azabicyclo[3.2.0]heptan-6-one were prepared under high pressure from [2 ] 2] cycloaddition of the pure enantiomers of 1-phenylethyl isocyanate and 2,3dihydrofuran. Their conformational preferences in solution and the absolute conÐgurations of the bridgehead carbon atoms were unambiguously determined by 1H NMR spectroscopy using tris[3-(2,2,2-triÑuoro-1-hydroxyethylidene)-d-camphorato]europium(III) and (R)-or (S)-1-(9-anthryl)-2,2,2-triÑuoroethanol (PirkleÏs alcohols). MM2 single-point energy calculations were consistent with the experimentally determined stereochemistry.