2,4-Diene-1,6-diones and 2-Acyl-3-cyclopenten-1-ols by Double Friedel-Crafts Acylation of Tricarbonyl(diene)iron Complexes
β Scribed by Directeur de Recherche au CNRS Michel Franck-Neumann; Dr. Madjid Sedrati; Dr. Mohamed Mokhi
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 235 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0044-8249
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β¦ Synopsis
A further aspect emerges from a comparison of the Si-Si bonds in 1, 2, and 4 : if one assumes that the bonds of the Si, ring in 1 are arched, then the "analog calculation" with a model kit'" using the Si-Si distance of 251 pm gives a value of 265 pm for the linear bond. This would then be the "normal" length of an Si-Si bond between two atoms with /err-butyl groups as substituents.
π SIMILAR VOLUMES
downfield. Thus on complex formation of (/), additional shielding and deshielding effects occur which can be explained in terms of a diamagnetic ring current in complex (2). We therefore propose the homoaromatic structure (2a) for the complex. Further support for this assignment comes from the fact
6-(Triphenylphosphonio-3Π-cyclopentadienyl)-2,3,5-trihalocyclohexa-2,5-diene-1,4-diones (2) are a new class of phosphorus containing dyes that behave as weak bases. Mono-protonation occurs at the cyclopentadiene ring leading to three isomers as assessed by NMR. The kinetics of the protonation were s