Mechanism of the Allylic Rearrangement of Allyloxo Metal Oxo Complexes: An Ab Initio Theoretical Investigation
✍ Scribed by Stéphane Bellemin-Laponnaz; Jean Pierre Le Ny; Alain Dedieu
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 315 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0947-6539
No coin nor oath required. For personal study only.
✦ Synopsis
The mechanism of the isomerization of allyl alcohols by the 1,3transposition of a hydroxy group, which is catalyzed by transition metal complexes in a high oxidation state, has been investigated by ab initio quantum chemical calculations for a trioxorhenium catalyst. The calculations point to a cyclic transition state that consists of a perrhenate anionic moiety and an allylic cationic group. This is similar to the transition state found for the [3,3] sigmatropic rearrangement in allyl formate. The energy barrier is lower in the organometallic case. The calcula-tions also suggest that the kinetic discrimination that is observed experimentally for the catalyzed cis ± trans isomerization of hex-1-en-3-ol is due to microsolvation effects of the corresponding transition states by the alcohols that are present in the reaction medium. All these features are explained in terms of orbital interactions present in the transition state.