摘要:

AbstractFollowing a survey of the asymmetric hydrogenation of prochiral olefins with transition metal/phosphane catalysts, the problem of chirality transfer from the optically active ligands of the catalyst to the substrate is discussed. A new concept for this chirality transfer is introduced; the conformational analysis of model compounds as well as the development of catalysts for enantioselective hydrosilylation demonstrate the usefulness of this concept.

ISSN:0570-0833    

DOI:10.1002/anie.198308973

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractPhosphorus ylides are not only classical reagents in organic chemistry, but also play an increasingly important role as novel components in organometallic compounds. These metallic “ylide complexes” are either synthesized from “preformed ylides” and coordination compounds by addition or substitution, on the building block principle, or they are formed, in sometimes complicated reactions, from phosphanes, metal complexes, and C1substrates in the coordination sphere of the metals. The resulting metal‐carbon bonds are greatly modified in their properties by the immediate presence of the phosphonium center and often belong to the most stable of M‐C structural units. The metal can come from any group of the periodic table, including the lanthanoids and actinoids. Numerous preparative and structural studies are gradually enabling us to gain an overall picture of the scope of this area

ISSN:0570-0833    

DOI:10.1002/anie.198309071

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractElectron‐rich, half‐sandwich complexes of the type CnRnML2or CnRnMLL′ are built up of an aromatic five‐ or six‐membered ring, a d8‐metal, and either a pair of two‐electron donors or an equivalent chelating ligand. Such complexes behave like Lewis bases and react with a wide variety of electrophiles, El or ElX, to form products with a new metal‐element bond. According to their reactivity they are comparable to the Vaska‐type compounds. Certain of the products obtained after addition of the electrophile undergo interesting subsequent reactions in which, for example, metal complexes containing molecules that are unstable in the free state, such as CS, CSe, CH2S, CH2Se, CH2Te, CH3CHS, CH3CHSe, CH2CS, CH2CSe, and CH2CTe are formed. Moreover, cycloadditions as well as reactions with coordinatively unsaturated transition‐metal compounds which result in formation of heterometal binuclear complexes demonstrate that the metal bases CnRnML2and CnRnMLL′ are valuable synthetic building blocks. Furthermore, very recent investigations have indicated links between metal basicity

ISSN:0570-0833    

DOI:10.1002/anie.198309271

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

Abstract“Modifications” of carbon—as long as they predominantly have the layered graphite structure—exhibit the following properties: (1) electrical conductance, (2) the ability to accomodate ions or molecules between the layers of the lattice, and (3) the ability to reactviafunctional groups at their surfaces (largely at the layer edges). The first of these properties has led to carbon being used as an “inert” electrode material; this aspect will not be considered in this article. The combination of the first and second properties leads to the possibility of electrochemical intercalation. This aspect of black carbon's properties will be described, using both literature data and our own results, in terms of both the basic information and the methodology associated with its uses. In addition to the formation of graphite salts the origin of graphite oxide and the various methods which have been used to analyze these materials will be reviewed. The functional groups [(cf. 3) above] can also be reacted electrochemically. Here, particular emphasis will be placed on detailed results obtained from chemically modified carbon electrodes and also from surface oxides and fluorides. Reference will be made to the technological uses of surface oxidized carbon fibers in composite materials and also generally to possible future uses of graphite base

ISSN:0570-0833    

DOI:10.1002/anie.198309501

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe complete manuscript of this communication appears in:Angew. Chem. Suppl. 1983, 1463. DOI:10.1002/anie.198314630

ISSN:0570-0833    

DOI:10.1002/anie.198309762

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe complete manuscript of this communication appears in:Angew. Chem. Suppl. 1983, 1477. DOI:10.1002/anie.198314770

ISSN:0570-0833    

DOI:10.1002/anie.198309771

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe complete manuscript of this communication appears in:Angew. Chem. Suppl. 1983, 1493. DOI:10.1002/anie.198314930

ISSN:0570-0833    

DOI:10.1002/anie.198309781

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe complete manuscript of this communication appears in:Angew. Chem. Suppl. 1983, 1543. DOI:10.1002/anie.198315430

ISSN:0570-0833    

DOI:10.1002/anie.198309791

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198309801

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198309811

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY