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NMR and quantum-chemical study of the stereochemistry of spiroepoxides obtained by oxidation of (Z)-3-arylidene-1-thioflavan-4-ones

✍ Scribed by Gábor Tóth; József Kovács; Albert Lévai; Erich Kleinpeter; Andreas Koch

Publisher
John Wiley and Sons
Year
2001
Tongue
English
Weight
179 KB
Volume
39
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

Epoxidation of (Z)‐3‐arylidene‐1‐thioflavan‐4‐ones (1) yielded trans,cis (2) and trans,trans (3) isomers. The structure and signal assignments were elucidated by extensive application of one‐ and two‐dimensional ^1^H and ^13^C NMR spectroscopy. The conformational analysis was achieved by the application of ^3^J(C,H) couplings and ab initio MO calculations. Both the preferred ground‐state conformers (envelope‐A conformations) obtained as global minima of the HF ab initio structures and the ^13^C chemical shifts calculated by the GIAO method from the global minima structures of the trans,cis and trans,trans isomers are in agreement with the experimentally obtained NMR results. Copyright © 2001 John Wiley & Sons, Ltd.

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