نتایج جستجو برای: triphenylphosphine
تعداد نتایج: 925 فیلتر نتایج به سال:
We present an ab initio investigation of structural, electronic, catalytic, and selective properties of the ligand-covered gold nanoparticle Au55(PPh3)12Cl6 and associated model clusters. The catalytic activity of the Au55(PPh3)12Cl6 nanoparticle in the presence of O2 stems from a combined effect of triphenylphosphine ligands and surface structure of the "magic-number" quasi-icosahedral Au55 co...
protonation of the highly reactive 1:l intermediate produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate by 2- hydroxyacetophenone leads to vinyltriphenylphosphonium salt, which undergoes aromatic electrophilic substitution reaction with the conjugate base to produce compounds 4,5, and 6 in 1 : 1.2:0.5 ratios
an efficient three-component reaction of dialkyl acetylendicarboxylates and 2-pyrrolidin in the presence of triphenylphosphine produces dialkyl 2-(2-pyrrolidin-n-yl)-3-(triphenylphosphanylidene)succinate. these phosphoranes undergo mild intramolecular wittig reaction to produce dialkyl (e)-2-(4,5-dihydro-3h-pyrrol-2-yl)fumarate in excellent yields.
A 1:1 co-crystal of rac-trans-1,2-C(6)H(10)(OH)(2) and (C(6)H(5))(3)PO has been found that is unusual because there are no strong interactions between the two kinds of molecules, which are segregated into layers. Furthermore, neither pure rac-1,2-cyclohexanediol (CHD) nor pure triphenylphosphine oxide (TPPO) has any obvious packing problem that would make the formation of inclusion complexes li...
An efficient three-component reaction of dialkyl acetylendicarboxylates and 2-Pyrrolidin in the presence of triphenylphosphine produces dialkyl 2-(2-Pyrrolidin-N-yl)-3-(triphenylphosphanylidene)succinate. These phosphoranes undergo mild intramolecular Wittig reaction to produce dialkyl (E)-2-(4,5-dihydro-3H-pyrrol-2-yl)fumarate in excellent yields.
A simple and efficient synthesis of some polyfunctionalized pyrrole derivatives by a triphenylphosphine-promoted condensation reaction between dialkyl acetylenedicarboxylates, arylglyoxals, and ammonium acetate is described. This present method carries several advantages, such as good yields, a simple procedure, non-hazardous reaction conditions and starting from easily accessible...
The chiral oxazaborolidinium salts 1 and 2 are excellent catalysts for the enantioselective cyanosilylation of a wide variety of aldehydes (see Table 1) using trimethylsilyl (TMS) cyanide and triphenylphosphine oxide as the source of a new reactive cyanide donor. This donor appears to be the isocyanophosphorane Ph3P(OTMS)(N=C:) (4). The novel process described herein has several advantages: pre...
The 1 : 4 and 1 : 2 complexes of silver perrhenate and triphenylphosphine, [(Ph3P)4Ag](+) ReO4(-) and [(Ph3P)2AgReO4]2, have been prepared and their structures determined in the solid state by X-ray diffraction. The former is composed of independent ions, while in the latter the ions are aggregated into cyclic dimers. The silver centers are tetracoordinated including contact with two bridging p...
Two new atropisomeric 4-aminopyridine-based nucleophilic catalysts containing terphenyl ‘blocking groups’ have been prepared and evaluated for kinetic resolution (KR) of aryl alkyl sec-alcohols. One of these biaryls is shown to be the most selective atropisomeric catalyst yet prepared for several sec-alcohols but its low reactivity makes it non-optimal for use at room temperature (rt). Optimisa...
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