Ullmann diaryl ether synthesis: rate acceleration by 2,2,6,6-tetramethylheptane-3,5-dione.
[reaction: see text]. In the copper salt catalyzed ether formation from aryl bromides or iodides and phenols, 2,2,6,6-tetramethylheptane-3,5-dione (TMHD) was found to greatly accelerate the ordinarily difficult reaction, making it occur under more moderate temperatures and reaction times. A series of aryl halides and phenols were shown to form ethers in NMP as the solvent, cesium carbonate as the base, and CuCl and TMHD as the catalysts. The reaction was shown to tolerate electron-rich aryl bromides and electron-neutral phenols.
Buck
Elizabeth
E
Department of Process Research, Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, USA.
Song
Zhiguo Jake
ZJ
Tschaen
David
D
Dormer
Peter G
PG
Volante
R P
RP
Reider
Paul J
PJ
D002384:Catalysis; D003300:Copper; D004987:Ethers / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D007659:Ketones / Q000138:chemical synthesis*; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy
D004987:Ethers; D007202:Indicators and Reagents; D007659:Ketones; D008024:Ligands; D003300:Copper; C014515:dipivaloylmethane