tolerates aerobic conditions. A Hammett study in the reaction of para-substituted benzhydryl alcohols shows negative σ values, indicating a build-up of cationic charge during the rate-determining sp3 C–O bond-cleavage step. The inverse kinetic solvent isotope effect (KSIE = 0.6) is consistent with a specific acid catalysis mechanism. This simple protocol can be performed under mild conditions in an atom-economic
Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>·xH<sub>2</sub>O on silica: an efficient and low-cost catalyst for the direct nucleophilic substitution of alcohols in solvent-free conditions
Fe2(SO4)3·xH2O on silica has been found to be a novel efficient catalyst for the direct nucleophilic substitution of alcohols in solvent-free conditions. In this reaction system, the alcohols can react with various nucleophilic reagents for the convenient construction of C–C bonds and C–N bonds with the benefits of high conversion, no requirement to use excessive amounts of the nucleophile, only a catalytic amount of iron catalyst required, solvent-free and benign reaction conditions, and the feasible reusability of the catalyst.
Direct nucleophilic substitution reaction of alcohols mediated by a zinc-based ionic liquid
作者:Anlian Zhu、Lingjun Li、Jianji Wang、Kelei Zhuo
DOI:10.1039/c0gc00763c
日期:——
A zinc-based ionic liquid ([CHCl][ZnCl2]2) was found to be an excellent reaction medium for the direct nucleophilicsubstitutionreactions of alcohols. The high conversion, high selectivity, easy separation procedure, catalyst reusability and no necessity of excessive nucleophiles make the chemical process cleaner. This reaction was believed to work through the carbocation mechanism and the existence