The direct benzylation of electrophilic alkenes with alkylbenzenes has been achieved by decatungstate photocatalysis in a high ionic strength medium (5:1 acetonitrile/water mixed solvents, 0.5M lithium perchlorate). The reaction has been extended to ring-substituted (Cl, F, CN) toluenes and further alkylbenzenes. Intramolecular selectivity (p-cymene, 4-methylanisole) and deuteration effects support the atom transfer character of the process that, however,
requires a sufficient stabilization of the intermediate polar exciplex to occur. The reactivity of the decatungstate anion is compared with that of aromatic ketones, the benchmark of photochemical hydrogen/ electron transfer processes.
Authors
Hisham Qrareya
Davide Ravelli
Maurizio Fagnoni
and Angelo Albini.
Pages From
2891
Pages To
2899
Journal Name
Adv. Synth. Catal.
Volume
1
Issue
355
Keywords
benzylation; CH bond activation; photocatalysis; polyoxometalates; radicals
Project
the Italian Ministry of Foreign Affairs through the E-PLUS project (Enhancement of the Palestinian University System).
Abstract