نتایج جستجو برای: pd substitution
تعداد نتایج: 114443 فیلتر نتایج به سال:
Well-established, traditional Kumada cross-couplings involve preformed Grignard reagents in dry ethereal solvent that typically react, e.g., with aryl halides via Pd catalysis to afford products of net substitution. Therefore, in the work described, which appears to be counterintuitive, exposure of these same aromatic halides to catalytic amounts of Pd(II) and excess magnesium metal in pure wat...
The syntheses of novel Pd complexes with germylene and stannylene ligands are reported. [MeN(CH2CH2NC6F5)2Sn]4Pd (2) and [MeN(CH2CPh2O)(CH2CH2O)Ge]4Pd (8) were obtained by different methods including ligand substitution in (Ph3P)4Pd or by the reaction of the free corresponding germylene or stannylene with (Ph3P)2PdCl2 or Pd(OAc)2. Crystal structures of complexes 2, 8 were determined by single c...
Chiral carbohydrate-based diphosphites were used for Pd-catalysed asymmetric allylic substitution (alkylation, amination, phosphination) in neat ionic liquids (ILs). Pyrrolidinium-based IL led to the best activities, allowing an efficient catalyst immobilization. In the allylic amination (TOF > 3100 h(-1)), the catalyst could be recycled nine times preserving both activity and enantioselectivity.
A set of complex tricyclic compounds containing several functional groups and multiple stereogenic centers has been prepared in only two steps with excellent diastereo- enantioselectivities. The synthesis takes advantage the highly versatile enantioselective Pd-catalyzed allylic substitution simple cyclic acetates or carbonates to form chiral 1,6-, 1,7- 1,8-enynes, which are then diastereoselec...
The regioselective mercuration of tetraalkylated calix[4]arenes with Hg(OCOCF3)2 leads to the formation of meta-substituted products which enabled Pd-catalysed intramolecular bridging within the calixarene skeleton. Bridged derivatives represent a completely novel substitution pattern in calixarene chemistry with extremely distorted cavities and possible applications in supramolecular chemistry.
A direct mercuration reaction combined with a subsequent Pd-catalyzed arylation was used to introduce the aryl moiety into the meta position of the calix[4]arene skeleton. The application of organomercurial intermediates thus allows the straightforward formation of meta-aryl-substituted derivatives representing a unique substitution pattern in calixarene chemistry.
Oraganometallic derivatives of palladium (o) have been isolated from the displacement reaction of Pd(Pφ3)4 with 1–substituted tetrazoline-5-thione with phenyl, orthotolyl, paratolyl, parachlorophenyl and benzoyl substitution in benzene medium. Most probable tetrahedral structure is assigned on the basic of elemental analysis, electronic, infrared, far infrared and 1H NMR spectral studies.
Reported here is a palladium catalyzed intramolecular acylcyanation of alkenes using α-iminonitriles. Through this method, highly functionalized indanones are synthesized in moderate to high yields using Pd(PPh3)4, without need for any additional ligands, and a common Lewis acid (ZnCl2). Additionally, the reaction tolerates substitution at various positions on the aromatic ring including electr...
Treatment of Ni(NCS)2(PMe2Ph)2 with organic isocyanides CN-R gave five-coordinate isocyanide Ni(II) complexes, Ni(CN-R)(NCS)2(PMe2Ph)2 (R = C6H3-2,6-Me2 (1), t-Bu (2)). Interestingly, the corresponding reaction of Ni(NCS)2(P(n-Pr)3)2 with 2 equiv. of CN-t-Bu gave an unusual compound, which exists as an ion pair of the trigonal bipyramidal cation [Ni(P(n-Pr)3)2(CN-t-Bu)3]2+ (3) and the dinuclear...
Parkinson's disease (PD) results from progressive degeneration of dopaminergic neurons. Most PD cases are sporadic, but some have pathogenic mutation in the individual genes. Mutation of the leucine-rich repeat kinase-2 (LRRK2) gene is associated with familial and sporadic PD, as exemplified by G2019S substitution. While constitutive expression of mutant LRRK2 in transgenic mice fails to induce...
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