Stereoelectronic Effects in Cyclic Sulfoxides, Sulfones, and Sulfilimines: Application of the Perlin Effect to Conformational Analysis

✍ Scribed by Tobias Wedel; Monika Müller; Joachim Podlech; Helmut Goesmann; Claus Feldmann

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 215 KB
• Volume: 13
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200601468

✦ Synopsis

Abstract

The ^1^J~CH~ coupling constants in conformationally constrained sulfoxides, bissulfoxides, sulfoxide‐sulfones, and sulfilimines derived from 2‐benzylidene‐1,3‐dithiane and 2‐(2,2‐dimethylpropylidene)‐1,3‐dithiolane were measured by means of HMQC and HSQC NMR experiments and the Perlin effects were calculated. The type and the relative configuration of SX groups (X= O, NTos) in these compounds have a strong influence on the magnitude of coupling constants for axial and equatorial CH bonds, respectively. Axial SO bonds give rise to a stereoelectronic effect on antiperiplanar axial CH bonds. The resultant weakening of the respective CH bonds leads to a smaller coupling constant than for a respective equatorial CH bond. Equatorial SO groups have an influence on β‐CH bonds through a homoanomeric effect. Here, the axial CH bond is weakened and a smaller coupling constant is measured. Sulfilimine groups show similar effects to sulfoxide groups.