Dynamic stereochemistry at sp2sp3 bonds part 1—the use of heterocyclic models for quantitative studies of steric effects of alkyl groups
✍ Scribed by Christian Roussel; Roger Gallo; Jacques Metzger; Jan Sandström
- Publisher
- John Wiley and Sons
- Year
- 1980
- Tongue
- English
- Weight
- 471 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
The barriers to rotation of the 3‐substituent in six 3‐RCH~2~‐4‐Me‐δ^4^‐thiazoline‐2‐thiones (R Me, Et, Pr, Isobu, Isopr,t‐Bu) and in two analogous methiodides have been measured by the ^1^H DNMR technique. The barriers are discussed in relation to the possible conformations of the transition states, and comparisons are made with barriers to rotation of the same substituents in other frameworks. It is concluded that the relative steric effects are strongly dependent on the framework and that, in general, a conformational analysis of the individual cases is necessary to understand the steric effects of alkyl groups.