Lanthanide-induced shifts of diastereotopic groups

✍ Scribed by Harold M. Bell

• Publisher: John Wiley and Sons
• Year: 1975
• Tongue: English
• Weight: 301 KB
• Volume: 7
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270070508

✦ Synopsis

Abstract

The chemical shift differences of diastereotopic protons in aliphatic acyclic alcohols, mostly of the type RCH~2~CR′R″(CH~2~)~n~OH, have been investigated. Fairly small amounts of Eu(dpm)~3~ cause the spectra of these materials to simplify dramatically; indeed, even diastereotopic protons rather far removed form the hydroxyl group give discrete signals in the presence of the shift reagent. Large shift differences were realized in the γ‐protons (n = 1) and the δ‐protons (n = 2), particularly if R is bulky and R' and R″ have different steric requirements. Semi‐quantitative conformational preferences can be determined from the data obtained.