1-Oxo-1,3-dithiolanes—synthesis and stereochemistry

✍ Scribed by Kalevi Pihlaja; Jari Sinkkonen; Gezá Stájer; Andreas Koch; Erich Kleinpeter

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 187 KB
• Volume: 49
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.2764

✦ Synopsis

Abstract

1‐Oxo‐1,3‐dithiolane (4) and its cis‐ and trans‐2‐methyl (5,6), ‐4‐methyl (7,8) and ‐5‐methyl (9,10) derivatives were prepared by oxidizing the corresponding 1,3‐dithiolanes (1–3) with NaIO~4~ in water. The oxides were purified and their isomers separated using thin layer chromatography. The structural characterization was carried out with ^1^H and ^13^C NMR spectroscopy and molecular modelling. The sulfoxides 4–6 and 8–10 attain two S(1) type envelopes (sometimes slightly distorted) the SO~ax~ envelope greatly dominating. Cis‐4‐methyl‐1‐oxo‐1,3‐dithiolane is a special case exhibiting both two closely related SO~ax~ (30 and 27%) as well as SO~eq~ (21 and 22%) forms [S(1) and C(4) envelopes, respectively]. The relative energies of these conformations, the values of ^1^H‐^1^H coupling constants and ^1^H and ^13^C chemical shifts were estimated by computational methods and they support well the conclusions based on the experimental data. Copyright © 2011 John Wiley & Sons, Ltd.