First heterogeneously palladium catalysed α-arylation of diethyl malonate

Pd exchanged NaY zeolites ([Pd(0)](-), [Pd(II)](-) and entrapped [Pd(NH3)(4)]) exhibit a good activity towards the alpha-arylation of carbonyl compounds using different para-substituted aryl bromides. Low Pd-concentrations (only 2 mol%) are required to observe interesting activity. The catalysts can easily be separated from the reaction mixture and reused without any loss in activity. For large-scale applications the alternative use of an insoluble base as K2CO3 seems to be promising. The electronic nature of the aryl halides plays a limited role concerning the rate of the reaction. (C) 2000 Elsevier Science S.A. All rights reserved.