Homeopathic ligand-free palladium as a catalyst in the heck reaction. A comparison with a palladacycle.
[reaction: see text] Ligand-free Pd(OAc)(2) can be used as a catalyst in the Heck reaction of aryl bromides as long as the amount of catalyst is kept between 0.01 and 0.1 mol %. At higher concentrations palladium black forms and the reaction stops. The actual catalyst is monomeric. Palladacycles merely serve as a source of ligand-free palladium in Heck reactions of aryl bromides.
de Vries
André H M
AH
DSM Pharma Chemicals-Advanced Synthesis, Catalysis & Development, P.O. Box 18, 6160 MD Geleen, The Netherlands.
Mulders
Jan M C A
JM
Mommers
John H M
JH
Henderickx
Huub J W
HJ
de Vries
Johannes G
JG