High-speed heck reactions in ionic liquid with controlled microwave heating.
Palladium-catalyzed Heck arylations in the polar and robust ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF(6)), have for the first time been accomplished under microwave irradiation. The couplings were efficiently performed in sealed tubes within 5-45 min of heating. Without significant reductions in yield, a phosphine-free ionic catalyst phase could be recycled in five successive 20 min reactions at 180 degrees C. The product was easily removed from the reaction medium by distillation.
Vallin
Karl S A
KS
Department of Organic Pharmaceutical Chemistry, Uppsala University, BMC, Box-574, SE-751 23 Uppsala, Sweden.
Emilsson
Per
P
Larhed
Mats
M
Hallberg
Anders
A