TY - JOUR
T1 - Komplexchemie und mechanismen metallkatalysierter cc-kupplungsreaktionen. II1 1 I. Mitteilung vgl. Ref. [9].. Oxidative addition von chloraromaten an Pd0-komplexe
T2 - synthese, struktur und stabilität von arylpalladium(II)-chloriden der phosphanreihe
AU - Herrmann, Wolfgang A.
AU - Broßmer, Christoph
AU - Priermeier, Thomas
AU - Öfele, Karl
PY - 1994/11/1
Y1 - 1994/11/1
N2 - Chlorobenzene and electron-poor aryl chlorides ClC6X (X = 4-NO2, 4-CHO, 4-CN, 4-H) add oxidatively to Pd(PPh3)4 or Pd(PPh3)2(dba) at 100-140°C to give complexes of the type trans-Pd(PPh3)2(C6H4-p-X)Cl (1a-d). Oxidative addition of electron-rich aryl chlorides ClC6H4Y (Y = 4-CH3, 4-CH3O) to Pd(PPh3)4 was expected to lead to the complexes trans-Pd(PPh3)2(C6H4Y)Cl (1e,f), but instead gave, in almost quantitative total yield, mixtures consisting of 90% trans-Pd(PPh3)2(Ph)Cl (1d) and 10% trans-Pd(PPh3){PPh2(C6H4-p-Y )}(Ph)Cl (3e,f). The stability of the oxidative addition products (1e-f) in solution was examined by means of in situ 1H and 31P NMR spectroscopy and mass spectrometry. It is shown that the complexes 1e and 1f, synthesized independently by halogen-exchange from the iodo derivatives, undergo a facile aryl-aryl exchange between the palladium center and the coordinated phosphine ligands, just in contrast to 1a-c. Subsequent intermolecular phosphine scrambling leads to further isomerisation which results in the formation of the observed reaction products 1d and 3e,f. Complexes with chelating phosphine ligands (P-P) of the type cis-Pd(P-P)(Ph)Cl (2a,b; P-P = dppe, dppp) are obtained by oxidative addition of chlorobenzene to Pd(P-P)(dba) or by simple phosphine exchange from 1d. Their identity is supported by single-crystal X-ray diffraction of 2b.
AB - Chlorobenzene and electron-poor aryl chlorides ClC6X (X = 4-NO2, 4-CHO, 4-CN, 4-H) add oxidatively to Pd(PPh3)4 or Pd(PPh3)2(dba) at 100-140°C to give complexes of the type trans-Pd(PPh3)2(C6H4-p-X)Cl (1a-d). Oxidative addition of electron-rich aryl chlorides ClC6H4Y (Y = 4-CH3, 4-CH3O) to Pd(PPh3)4 was expected to lead to the complexes trans-Pd(PPh3)2(C6H4Y)Cl (1e,f), but instead gave, in almost quantitative total yield, mixtures consisting of 90% trans-Pd(PPh3)2(Ph)Cl (1d) and 10% trans-Pd(PPh3){PPh2(C6H4-p-Y )}(Ph)Cl (3e,f). The stability of the oxidative addition products (1e-f) in solution was examined by means of in situ 1H and 31P NMR spectroscopy and mass spectrometry. It is shown that the complexes 1e and 1f, synthesized independently by halogen-exchange from the iodo derivatives, undergo a facile aryl-aryl exchange between the palladium center and the coordinated phosphine ligands, just in contrast to 1a-c. Subsequent intermolecular phosphine scrambling leads to further isomerisation which results in the formation of the observed reaction products 1d and 3e,f. Complexes with chelating phosphine ligands (P-P) of the type cis-Pd(P-P)(Ph)Cl (2a,b; P-P = dppe, dppp) are obtained by oxidative addition of chlorobenzene to Pd(P-P)(dba) or by simple phosphine exchange from 1d. Their identity is supported by single-crystal X-ray diffraction of 2b.
UR - http://www.scopus.com/inward/record.url?scp=0002845188&partnerID=8YFLogxK
U2 - 10.1016/0022-328X(94)85014-3
DO - 10.1016/0022-328X(94)85014-3
M3 - Artikel
AN - SCOPUS:0002845188
SN - 0022-328X
VL - 481
SP - 97
EP - 108
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
IS - 1
ER -