Oxidative Addition of Benzyliminium Tetraphenylborate to Pd(dba)(dppe): Synthesis and Catalytic Activity of [(dppe)Pd(dba){η1(N)-PhCH2N=CMe2}](BPh4)2

The synthesis and catalytic activity of the new dicationic PdII complex [(dppe)Pd(dba){η1(N)-PhCH2N=CMe2}](BPh4)2 from the Pd0 complex Pd(dba)(dppe) and [(PhCH2)HN=CMe2]BPh4 are described. [(PhCH2)HN=CMe2]BPh4 adds to Pd(dba)(dppe) under mild conditions through a selective N−H activation. The resulting species further reacts with [(PhCH2)HN=CMe2]BPh4 and generates N-benzyl-N-isopropylamine and [(dppe)Pd(dba){η1(N)-PhCH2N=CMe2}](BPh4)2. The latter catalyzes the dimerization of methyl acrylate (MA) and the co-oligomerization of MA with styrene. Significant changes of the selectivity in the dimerization of MA have been found, e.g. changing the solvent from methyl acrylate (mostly tail-to-tail, T-T, coupling) to the ionic liquid [bmim]BF4 (T-T and head-to-tail, H-T, coupling). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)