821786-06-5Relevant academic research and scientific papers
The mechanism for palladium catalyzed carbonylation of cinnamyl chloride
Van Haaren, Richard J.,Oevering, Henk,Kamer, Paul C.J.,Goubitz, Kees,Fraanje, Jan,Van Leeuwen, Piet W.N.M.,Van Strijdonck, Gino P.F.
, p. 3800 - 3805 (2004)
In the palladium catalyzed alkoxycarbonylation of cinnamyl chloride two mechanisms play a role. An associative mechanism was observed at low pressure, while an insertion mechanism was observed at high pressure or when an excess of ligand was used. Several putative intermediates of the catalytic alkoxycarbonylation have been synthesized and characterized, such as 5c of which an X-ray crystal structure was obtained.
Design of cationic mixed phosphine/n-heterocyclic carbene palladium(ii) π Allyl complexes as monoligated phosphine Pd(0) precatalysts: Synthesis, structural studies, catalysis, and reactivity
Normand, Adrien T.,Stasch, Andreas,Ooi, Li-Ling,Cavell, Kingsley J.
, p. 6507 - 6520 (2009/05/30)
Compounds of general formula [Pd(L)(NHC)(L′)]BF4 (where L = allyl or crotyl, NHC = tetrameth-ylimidazolin-2-ylidene (tmiy) or l,3-diisopropyl-4,5-dimethylimidazolin-2-ylidene (dipdmiy), and L′ = tertiary phosphine) have been prepared from the parent [Pd(L)Cl(NHC)(L′)] complexes and fully characterized. A perpendicular orientation of the NHC is observed in the solid state (X-ray) and in solution (NOESY). The crystal structures of these complexes reveal the double-bond character of the allyl trans to the phosphine ligand; for example, [Pd(η3-C 3H5)(tmiy)(PPh3)]BF4 (4d) displays C-C distances of 1.198 A (trans to P) and 1.374 A (trans to the NHC). The NHC-Pd-allyl precatalysts are thought to generate monoligated phosphine-Pd(0) active species by reductive elimination of 2-allylimidazolium following η3-η1 isomerization of the allyl group. This was observed in the case of [Pd(η3-C3H 5)(tmiy)(PCy3)]BF4 (4b), which successfully catalyzed the coupling of imidazolium salts with ethylene. The intriguing reactivity of 4b with Phi, yielding 2-phenylimidazolium selectively, is also reported.
