烯烃氢甲酰化反应研究进展

本文综述了烯烃氢甲酰化反应的催化剂从钴配合物到铑配合物和从均相催化体系到两相催化体系的发展过程。比较了三种催化剂和两个催化体系的特点、应用情况及研究工作进展.     

Complete graph conjecture for inner-core electrons: homogeneous index case

The complete graph conjecture that encodes the inner-core electrons of atoms with principal quantum number n >or= 2 with complete graphs, and especially with odd complete graphs, is discussed. This conjecture is used to derive new values for the molecular connectivity and pseudoconnectivity basis indices of hydrogen-suppressed chemical pseudographs. For atoms with n = 2 the new values derived with this conjecture are coincident with the old ones. The modeling ability of the new homogeneous basis indices, and of the higher-order terms, is tested and compared with previous modeling studies, which are centered on basis indices that are either based on quantum concepts or partially based on this new conjecture for the inner-core electrons. Two similar algorithms have been proposed with this conjecture, and they parallel the two "quantum" algorithms put forward by molecular connectivity for atoms with n > 2. Nine properties of five classes of compounds have been tested: the molecular polarizabilities of a class of organic compounds, the dipole moment, molar refraction, boiling points, ionization energies, and parachor of a series of halomethanes, the lattice enthalpy of metal halides, the rates of hydrogen abstraction of chlorofluorocarbons, and the pED(50) of phenylalkylamines. The two tested algorithms based on the odd complete graph conjecture give rise to a highly interesting model of the nine properties, and three of them can even be modeled by the same set of basis indices. Interesting is the role of some basis indices all along the model.     

Organosulfur compounds: electrophilic reagents in transition-metal-catalyzed carbon-carbon bond-forming reactions

Transition-metal-catalyzed carbon-carbon bond-forming reactions are among the most powerful methods in organic synthesis and play a crucial role in modern materials science and medicinal chemistry. Recent developments in the area of ligands and additives permit the cross-coupling of a large variety of reactants, including inexpensive and readily available sulfonyl chlorides. Their desulfitative carbon-carbon cross-coupling reactions (Negishi, Stille, carbonylative Stille, Suzuki-Miyaura, and Sonogashira-Hagihara-type cross-couplings and Mizoroki-Heck-type arylations) are reviewed together with carbon-carbon cross-coupling reactions with other organosulfur compounds as electrophilic reagents.     

Ruthenium(III)-catalyzed oxidation of thallium(i) by 12-tungstocobaltate(III) in hydrochloric acid medium

The reaction between thallium(I) and [Co^IIIW₁₂O₄₀]^5- in the presence of ruthenium(III) as catalyst proceeds viainitial outer-sphere oxidation of the catalyst to ruthenium(VI). The ruthenium(IV) thus generated will oxidize thallium(I) to an unstable thallium(II) which by reacting with oxidant gives the final product, thallium(III). The formation of ruthenium(II) by direct two-electron reduction of the catalyst by thallium(I) is thermodynamically less favorable. The reaction rate is unaffected by the [ H⁺ ], whereas it is catalyzed by chloride ion . The formation of reactive chlorocomplex,TlCl, in a prior equilibrium is the reason for the chloride ion catalysis. Increasing the relative permittivity of the medium increases the rate of the reaction, which is attributed to the formation of an outer-sphere complex between the catalyst and oxidant. This revised version was published online in June 2006 with corrections to the Cover Date.     

Diaminocarbene- and Fischer-carbene complexes of palladium and nickel by oxidative insertion: preparation, structure, and catalytic activity

Oxidative insertion of [Pd(PPh3)4] or [Ni(cod)2]/PPh3 into the C-Cl bond of various 2-chloroimidazolinium- and other -amidinium salts affords metal-diaminocarbene complexes in good to excellent yields. This procedure is complementary to existing methodology in which the central metal does not change its oxidation state, and therefore allows to incorporate carbene fragments that are difficult to access otherwise. The preparation of a variety of achiral as well as enantiomerically pure, chiral metal-NHC complexes (NHC = N-heterocyclic carbene) and metal complexes with acyclic diaminocarbene ligands illustrates this aspect. Furthermore it is shown that oxidative insertion also paves a way to prototype Fischer carbenes of Pd(II). Since the required starting materials are readily available from urea- or thiourea derivatives, this novel approach allows for substantial structural variations of the ligand backbone. The catalytic performance of the resulting library of nickel- and palladium-carbene complexes has been evaluated by applications to prototype Suzuki-, Heck-, and Kumada-Corriu cross-coupling reactions as well as Buchwald-Hartwig aminations. It was found that even Fischer carbenes show appreciable catalytic activity. Moreover, representative examples of all types of neutral and cationic metal-carbene complexes formed in this study have been characterized by X-ray crystallography.     

Homologies cyclique et de Hochschild de certains espaces homogènes quantiques

Nous quantifions certaines inclusions d'algèbres de Lie semi-simpleshg. Nous calculons les homologies associées aux quantifications, surC((h)), d'une part des algèbres de fonctions formelles surG/H, pourHG une inclusion de groupes de Lie semi-simples associée, et d'autre part des fonctions algébriques sur SL(2,C)/T.We quantize certain inclusions of semisimple Lie algebrashg. We compute the cyclic and Hochschild homologies for theC((h))-quantizations of

On methods for converting exhausters of positively homogeneous functions

In the paper we develop a method for converting a (not necessarily uniformly bounded) upper (lower) primal exhauster of a continuous positively homogeneous function to a lower (upper) primal exhauster of the same function. The method is based on representation of a continuous positively homogeneous function as a pointwise supremum (infimum) of an one-parameter monotone family of Lipschitz continuous positively homogeneous functions that is of independent interest.