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.
Department of Organic Pharmaceutical Chemistry, Uppsala University, BMC, Box-574, SE-751 23 Uppsala, Sweden.
Karl S A
KS
Vallin
Per
P
Emilsson
Mats
M
Larhed
Anders
A
Hallberg