Search results for "Elimi"
showing 10 items of 283 documents
Complexes of (CH3)2AuIII: synthesis, PMR and IR spectra
1975
Abstract The syntheses and reactivity of dimethylgold(III) complexes with multidentate ligands as TRIPHOS (i.e., 1,1,1-tris(diphenylphosphinomethyl)ethane) and TREN (i.e. 2,2′,2″-triaminotriethylamine) have been examined. I.r. spectra for the compounds in the solid state, conductivity and PMR data for solutions, lead to the assignment of an ionic formula [CH 3 ) 2 Au TRIPHOS] + [(CH 3 ) 2 AuCl 2 ] − where the gold(III) atoms are presumably four-coordinate. The complex (CH 3 ) 2 AuCl TREN in DMSO solution undergoes a reductive elimination reaction, as found for analogous dimethylgold(III) derivatives.
Multiple Roles of Isocyanides in Palladium-Catalyzed Imidoylative Couplings: A Mechanistic Study
2016
International audience; Kinetic, spectroscopic and computational studies examining a palladium-catalyzed imidoylative coupling highlight the dual role of isocyanides as both substrates and ligands for this class of transformations. The synthesis of secondary amides from aryl halides and water is presented as a case study. The kinetics of the oxidative addition of ArI with RNC-ligated Pd-0 species have been studied and the resulting imidoyl complex [(ArC=NR)Pd(CNR)(2)I] (Ar=4-F-C6H4, R = tBu) has been isolated and characterized by X-ray diffraction. The unprecedented ability of this RNC-ligated imidoyl-Pd complex to undergo reductive elimination at room temperature to give the amide in the p…
La delimitación de los espacios marítimos españoles
2000
I. INTRODUCCIÓN. II. LAS DELIMITACIONES PACTADAS. 1. Delimitaciones pactadas con Francia. 1.1. Delimitación de las aguas interiores en la desembocadura del Río Bidasoa y en la Bahía de Higuer. 1.2. Delimitación del mar territorial hispano-francés en el Golfo de Vizcaya (o de Gascuña). 1.3. Delimitación de la plataforma continental en el Golfo de Vizcaya (o de Gascuña). 2. Delimitación de la plataforma continental hispano-italiana en el Mar Mediterráneo. 3. Delimitación del mar territorial hispano-portugués en la desembocadura del Río Miño. III. LAS DELIMITACIONES PENDIENTES DE SOLUCIÓN. 1. La delimitación inacabada de los espacios marítimos en el Golfo de Vizcaya. 2. Problemas de delimitaci…
Diastereoselective Synthesis of Dialkylated Bis(phosphino)ferrocenes: Their Use in Promoting Silver-Mediated Nucleophilic Fluorination of Chloroquino…
2017
International audience; The diastereoselective synthesis of dialkylated ferrocenyl bis(phosphane)s bearing aryl, alkyl, and hetero- or polycyclic substituents on the phosphino groups is reported, together with their characterization in the solid state by X-ray structure analysis and in solution by multinuclear NMR spectroscopy. Introduction of various alkyl groups on the ferrocene backbone, namely, tert-butyl, isopropyl, and trimethylsilyl, has a significant influence on the stereoselectivity of the ensuing lithiation/phosphination reactions. Only the introduction of the tert-butyl groups ensures both a high yield and perfect diastereoselectivity, which leads to the exclusive formation of t…
Mechanistic details of the domino reaction of nitronaphthalenes with the electron-rich dienes. A DFT study
2008
Abstract The reaction of 1-nitronaphthalene ( 1 ) with the Danishefsky diene ( 2 ) to give the dihydrophenanthrene derivative 11 has been theoretically studied using DFT methods. This reaction is a domino process that is initialized by a polar Diels–Alder reaction between 1 and 2 to give the formally [2 + 4] cycloadduct 3 . The subsequent concerted elimination of nitrous acid ( 4 ) from 3 yields 11 . Analysis of the global reactivity indices as well as the thermodynamic data for this domino process indicate that while the large electrophilic character of 1 together with the large nucleophilic character of 2 are responsible for the participation of these reagents in a polar Diels–Alder react…
ansa-[(tert-Butylamino)(isodicyclopentadienyl)dimethylsilane]Zr(NMe2)2prepared by an amine-elimination reaction
2003
An amine-elimination reaction was used to obtain the title compound, i.e. (N-tert-butyl-N-[[(1,2,3,3a,7a-eta)-4,5,6,7-tetrahydro-4,7-methano-1H-inden-2-yl]dimethylsilyl]amido-kappaN)bis(N-methylmethanaminato-kappaN)zirconium(IV) or [isodiCpSiMe(2)N-tert-butyl]Zr(NMe(2))(2) (Cp is cyclopentadienyl), [Zr(C(16)H(25)NSi)(C(2)H(6)N)(2)], in very good yield. Treatment of isodiCpHSiMe(2)NH-tert-butyl with Zr(NMe(2))(4) leads to the formation of a yellow solid that can be purified by sublimation. The single-crystal structure of the product shows the exo complexation of the isodicyclopentadienyl ligand to the Zr atom. The Cp portion of this ligand is bonded to the Zr atom in a eta(5) manner, with a …
Efficient CNF Encoding of Boolean Cardinality Constraints
2003
In this paper, we address the encoding into CNF clauses of Boolean cardinality constraints that arise in many practical applications. The proposed encoding is efficient with respect to unit propagation, which is implemented in almost all complete CNF satisfiability solvers. We prove the practical efficiency of this encoding on some problems arising in discrete tomography that involve many cardinality constraints. This encoding is also used together with a trivial variable elimination in order to re-encode parity learning benchmarks so that a simple Davis and Putnam procedure can solve them.
Competenza territoriale e indagini collegate in materia di associazioni di tipo mafioso
2013
Il collegamento delle indagini costituisce un modulo investigativo inedito. La disciplina madre si rintraccia nella norma di cui all'art. 371 c.p.p.. Quanto ai delitti in materia di associazione di stampo mafioso è stata prevista però in fase di indagini una disciplina specifica all'art. 371 bis c.p.p., predisponendosi un modulo investigativo ad hoc, che assurge a criterio primus inter pares rispetto a quello generale. Il contributo analizza la disciplina in particolare della competenza territoriale e delle indagini collegate, con un ultimo sguardo ai profili e i limiti di Eurojust.
Towards an intrinsic nucleofugality scale: the leaving group (lg) ability in ch(3)lg model system
2006
Abstract For an important class of organic reactions in which a fragment of the reactants, the leaving group (LG) or nucleofuge (Z), is detached of the substrate bearing the bonding electron pair, the global electrophilicity index of the CH3LG system is proposed as a reliable descriptor of the intrinsic nucleofugality of the LG. The model is illustrated by ranking within a unique relative scale, the LG ability of 28 functional groups commonly involved in substitution and elimination reactions in organic chemistry.
PHOSPHORORGANISCHE VERBINDUNGEN 1121REAKTIVITÄT UND SELEKTIVITÄT VON VINYLPHOSPHONIUMSALZEN UND VINYLPHOSPHINOXIDEN GEGENÜBER NUCLEOPHILEN
1984
Abstract As a result of competition reactions triphenylvinylphosphonium bromide 1 is SH-selective. But the reactivity is significantly reduced in comparison to the vinyl sulfones. The elimination reaction (b) is also slowed down compared with the cleavage of the corresponding sulfones. In diphenylvinylphosphine oxide 2 the SH-selectivity is preserved. The rate of the reactions (a) and (b) is so extremely slow that 2 has no chance as a SH-protective reagent. Triphenyl-vinylphosphoniumbromid 1 reagiert in Konkurrenzversuchen mit RXH (X=O, S, NH) SH-selektiv bei deutlich reduzierter Reaktivitat im Vergleich zu den Vinylsulfonen. Auch die Eliminierung nach (b) verlauft langsamer als bei analoge…