Abstract
Rate studies have shown that the activation of halogenobenzenes towards nucleophilic attack by methoxide ion in methanol increases through the series of π-attached residues: (OC)3Cr chlorobenzene > chlorotoluene. Rates of reaction with methoxide are retarded in the presence of NaClO4 or LiCl, but accelerated when the methanol solvent is diluted with tetrahydrofuran or 1,4-dioxan. Fluorobenchrotrene (OC)3Cr(η6-PhCl) is slightly more reactive towards ethoxide in ethanol than towards methoxide in methanol. Evidence has been obtained that the cationic (halogenoarene)metal complexes readily form ion-pairs with methoxide, resulting in a reduction in their reactivity towards nucleophilic attack. Methoxide adds to [(π-methoxyarene)Mn(CO)3]+ complexes to give (η5-cyclohexadienyl) products which are reconverted into the cations by acid treatment.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have