Phosphinoferrocenyl-terminated amidoamines: Synthesis and catalytic utilization in palladium-mediated C-C bond forming reactions
Abstract
1'-(Diphenylphosphino)-1-(N-butylcarbamoyl)ferrocene (P1) and the analogous higher amides P2-4 related to the first-generation PAMAM dendrimers bearing up to four 1'-(diphenylphosphino)feffocen-1-yl terminal groups were synthesized by amidation of the respective (poly)amines with 1'-(diphenylphosphino)ferrocenecarboxylic acid (Hdpf). Testing of amides P1-4 as ligands for palladium-catalyzed Suzuki and Heck coupling reactions has shown that these amidophosphines preserve the activity of the single phosphinoferrocenyl unit, giving rise to active catalysts in both C-C forming reactions.
Even for such relatively small systems, a positive influence of the dendritic assembly was notable as the compounds bearing a higher number of the phosphinofeffocenyl termini afforded faster reacting catalytic systems at the same palladium loading and P-to-Pd ratio.