Structural studies of carbanionic species α to a phosphoryl group; anion from ketophosphonate comparison with related enoxysilanes and p-ylid
✍ Scribed by Tekla Bottin-Strzalko; Jacqueline Seyden-Penne; Marie-José Pouet; Marie-Paule Simonnin
- Book ID
- 102526373
- Publisher
- John Wiley and Sons
- Year
- 1982
- Tongue
- English
- Weight
- 384 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
The structure of the carbanionic species 4 formed from diethyl(2‐oxopropyl)phosphonate and t‐BuOK has been studied by ^1^H, ^13^C and ^31^P NMR. In an associating medium (pyridine), a single chelated (C) carbanionic species 4__Z__ (C) is observed. Two slowly interconverting species 4__Z__ and 4__E__ co‐exist when the anion‐cation interaction is loose, i.e. in Me~2~SO and when the gegenion K^+^ is complexed to (2,2,2)cryptand in Me~2~SO. The anionic carbon of 4__Z__ and 4__E__ is planar, and they have a strong enolate character as shown by the barrier to rotation around the C‐1C‐2 bond (Δ__G~c~__‡∼92 KJ mol^−1^). Their structures are compared to those of the related E and Z 1‐diethylphosphonato‐2‐trimethylsilyloxypropenes and to (acetylmethylene)triphenylphosphorane.