Palladium-Catalyzed Methylation of Aryl and Vinyl Halides by Stabilized Methylaluminum and Methylgallium Complexes

Jochanan Blum*, Dmitri Gelman, Waël Baidossi, Eduard Shakh, Ayelet Rosenfeld, Zeev Aizenshtat, Birgit C. Wassermann, Michael Frick, Bernd Heymer, Stefan Schutte, Sonja Wernik, Herbert Schumann

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

The intramolecularly stabilized mono- and dialkylaluminum complexes 1a, 2, 3, 4a, 5a, 5c, 6a, 6c, 7, 8, and 9 in the presence of palladium catalysts, cross-alkylate aryl, vinyl, and benzyl bromides and iodides under mild standard laboratory conditions. Aryl bromides with carbonyl substituents or benzylic halides are converted partially into dialkyl compounds. Under similar conditions, the analogous stabilized dimethylgallium complexes 1b, 4b, 5b, 6b, and 10 methylate aryl and vinyl bromides and iodides in a highly selective manner. Substituted bromobenzenes XC6H4Br, where X = CHO, COPh, CO2Et, CN, NO2, Cl, CH2Br, or CH=CHCOPh, are methylated by the organogallium reagents usually only at the aromatic ring halogen atom to give substituted toluenes as single products. The methylation rates were shown to depend on the nature of the chelating ligands, on the solvent, and on the type of palladium catalyst employed.

Original languageAmerican English
Pages (from-to)8681-8686
Number of pages6
JournalJournal of Organic Chemistry
Volume62
Issue number25
DOIs
StatePublished - 1997

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