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Palladium‐Catalyzed Cross‐Methylation of Haloarenes Possessing Active Hydrogen Atoms by Intramolecularly Stabilized Dimethylindium and Dimethylaluminum Reagents
Author(s) -
Jaber Nimer,
Gelman Dmitri,
Schumann Herbert,
Dechert Sebastian,
Blum Jochanan
Publication year - 2002
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200205)2002:10<1628::aid-ejoc1628>3.0.co;2-c
Subject(s) - chemistry , palladium , catalysis , reagent , demethylation , bromine , hydrogen , methylation , medicinal chemistry , hydrolysis , organic chemistry , biochemistry , gene , gene expression , dna methylation
While the intramolecularly stabilized aluminum complex [(CH 3 ) 2 AlOCH 2 CH 2 N(CH 3 ) 2 ] 2 ( 2a) reacts readily with 4‐bromophenol to give methane and [(4‐BrC 6 H 4 O) 2 AlOCH 2 CH 2 N(CH 3 ) 2 ] 2 ( 7 ), the demethylation of the analogous indium complex [(CH 3 ) 2 InOCH 2 CH 2 N(CH 3 ) 2 ] 2 2c is very slow. This inertness of 2c enables it to cross‐methylate bromophenols and other bromoarenes with active hydrogen atoms in the presence of soluble palladium phosphane catalysts. The cross‐methylation by 2c can be carried out under an ambient atmosphere. The ring‐bound bromine atoms in 7 are replaced by CH 3 groups when treated with an excess of the methylation reagent 2a , and the resulting aluminum cresolate liberates 4‐methylphenol upon hydrolysis. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)