Mechanistic variations and rate effects of alkoxy and thioalkoxy substituents on anionic oxy-cope rearrangements

Citation
F. Haeffner et al., Mechanistic variations and rate effects of alkoxy and thioalkoxy substituents on anionic oxy-cope rearrangements, J AM CHEM S, 121(50), 1999, pp. 11880-11884
Citations number
12
Categorie Soggetti
Chemistry & Analysis",Chemistry
Journal title
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
ISSN journal
00027863 → ACNP
Volume
121
Issue
50
Year of publication
1999
Pages
11880 - 11884
Database
ISI
SICI code
0002-7863(199912)121:50<11880:MVAREO>2.0.ZU;2-T
Abstract
The effects of thiomethoxy and methoxy substituents on the rates and the me chanisms of anionic oxy-Cope rearrangements were investigated with density functional theory (B3LYP/6-31+G*), Thiomethoxy substituents at positions C4 or C6 of 3-oxido-1,5-hexadienes cause acceleration and promote heterolytic cleavage rather than concerted rearrangement, and the Cope product is form ed via a stepwise pathway. The corresponding methoxy substituents impede he terolytic cleavage and slow the concerted rearrangement.