Palladium catalyzed cross-methylation of bromoheterocycles with intramolecularly stabilized dimethyl indium reagents

• Published in: Journal of heterocyclic chemistry Vol. 40; no. 4; pp. 565 - 567
• Main Authors: Jaber, Nimer, Blum, Jochanan, Schumann, Herbert
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley-Blackwell 01-07-2003; Wiley‐Blackwell
• ISSN: 0022-152X; 1943-5193
• DOI: 10.1002/jhet.5570400402

Although the intramolecularly stabilized [(3‐dimethylamino)propyl]dimethylaluminum (1a) fails to undergo palladium‐catalyzed cross‐coupling with bromopyridines and with bromofuran derivatives, the analogous gallium and indium reagent 1b and 1c smoothly cross‐methylate these and other bromoheterocycles. The cross‐coupling can be performed also with the dimeric indium and gallium compounds bis(μ‐[2‐(dimethylamino)ethanolato‐N,O:O]tetramethyldigallium and ‐diindium (2b and 2c, respectively). The indium reagent is fairly air‐stable and the reactions can be carried out under ambient conditions. The yields are generally very high but are influenced by steric and electronic effects.