Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska dolina CH-2, SK-842 15 Bratislava, Slovak Republic;Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska dolina CH-2, SK-842 15 Bratislava, Slovak Republic;Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzenes University, Heinrichstrasse 28, Graz, Austria;
Viera Polackova;Stefan Toma;C. Oliver Kappe;
The palladium-catalyzed arylation of rac-(E)-3-acetoxy-1,3-diphenylprop-1-ene with arylboronic acids was studied under controlled microwave irradiation conditions. A variety of different catalysts, bases, and solvents were explored in order to achieve optimum yields in the shortest possible reaction times. The best isolated yields were obtained using Pd_2(dba)_3·CHCl_3/PPh_3 as the catalytic system, potassium phosphate monohydrate as the base, and toluene/H_2O as a solvent system. Microwave irradiation using 5 mol % of the palladium catalyst for 90 s (max. temp 170℃) generally afforded the cross-coupling products in good to excellent yields.