Carbon-13 magnetic resonance study of spiro compounds

✍ Scribed by D. Zimmermann; R. Ottinger; J. Reisse; H. Christol; J. Brugidou

• Publisher: John Wiley and Sons
• Year: 1974
• Tongue: English
• Weight: 633 KB
• Volume: 6
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270060610

✦ Synopsis

Abstract

A large series of cyclohexane and cyclopentane spiro compounds has been studied by carbon‐13 NMR. Increments have been derived in terms of α, β, γ spiro substituent effects, one ring being considered as the substituent of the other. As usual α and β effects are paramagnetic and γ effects are diamagnetic. They are compared with the corresponding effects associated with the introduction of a gem dimethyl group into a cyclohexane or cyclopentane ring. The size of the two rings involved in the spirane structure has a marked influence especially on the chemical shift of the spirane carbon atom. Comparison between monospiro and dispiro derivatives gives information about the so‐called 1,5 or δ effect which is paramagnetic. From an analytical point of view, carbon‐13 NMR appears to be a powerful method of detecting the spirane structure, apparently including the relative size of the rings.