352670-77-0Relevant academic research and scientific papers
Stille cross-coupling of a racemic planar-chiral ferrocene and crystallographic trace analysis of catalysis intermediates and by-products
Weber, Immo,Heinemann, Frank W.,Bakatselos, Panagiotis,Zenneck, Ulrich
, p. 834 - 845 (2008/03/12)
A pressure-controlled procedure for the SN1 reaction of rac-1-[(dimethylamino)methyl]-2-(tributylstannyl)ferrocene (1) to rac-1-(phthalimidomethyl)-2-(tributylstannyl)ferrocene (2) was developed. Pd0-Catalyzed Stille coupling of 2 with iodobenzene afforded rac-1-phenyl-2-(N-phthalimidomethyl)-ferrocene (5) in 74% yield; after trace enrichment by crystallization of the combined mother liquors, one single crystal of each, 5, catalysis intermediate trans-iodo(σ-phenyl) bis(triphenylarsino)palladium(II) (7), trans-diiodobis(triphenylarsino) palladium(II) (8), and rac-2,2′-bis(phthalimidomethyl)-1,1′- biferrocene (9) could be isolated by crystal sorting under a microscope and characterized by X-ray crystal structure analysis. Furthermore, 5 was deprotected to amine (11), which does even survive the Birch reduction to rac-1-(aminomethyl)-2-(cyclohexa-2,5-dienyl)ferrocene (12).
Mechanism of the Stille reaction catalyzed by palladium ligated to arsine ligand: PhPdl(AsPh3)(DMF) is the species reacting with vinylstannane in DMF
Amatore, Christian,Bahsoun, Ali A.,Jutand, Anny,Meyer, Gilbert,Ndedi Ntepe, Alexandre,Ricard, Louis
, p. 4212 - 4222 (2007/10/03)
The kinetics of the reaction of PhPdI(AsPh3)2 (formed via the fast oxidative addition of Phl with Pd0(AsPh3)2) with a vinyl stannane CH2=CH-Sn(n-Bu)3 has been investigated in DMF. This reaction (usually called transmetalation step) is the prototype of the rate determining second step of the catalytic cycle of Stille reactions. It is established here that the transmetalation proceeds through PhPdI(AsPh3)(DMF), generated by the dissociation of one ligand AsPh3 from PhPdI(AsPh3)2. PhPdI(AsPh3)(DMF) is the reactive species, which leads to styrene through its reaction with CH2=CH-SnBu3. Consequently, in DMF, the overall nucleophilic attack mainly proceeds via a mechanism involving PhPdI(AsPh3)(DMF) as the central reactive complex and not PhPdI(AsPh3)2. The dimer [Ph2Pd2(μ2-I)2 (AsPh3)2] has been independently synthesized and characterized by its X-ray structure. In DMF, this dimer dissociates quantitatively into PhPdI(AsPh3)(DMF), which reacts with CH2=CH-SnBu3. The rate constant for the reaction of PhPdI-(AsPh3)(DMF) with CH2=CH-SnBu3 has been determined in DMF for each situation and was found to be comparable.
