8A Chemical Reviews, 2000, Vol. 100, No. 8
In Color on the Front Cover (Top, left) Unsaturated organic compounds including alkenes, alkynes, dienes, and isonitriles insert into silicon-containing bonds in the presence of group 10 metal complex catalysts. See “Transition-Metal-Catalyzed Additions of Silicon−Silicon and Silicon−Heteroatom Bonds to Unsaturated Organic Molecules” by Michinori Suginome and Yoshihiko Ito, p 3221. (Top, right) 1,1-, 1,2-, 1,3-, and 1,4-dicarbanionic reactivity can be achieved with organotitanium intermediates generated in various ways. The 1,2-dicarbanionic equivalents generated from titanium alkoxides and Grignard reagents are particularly useful as they open up versatile routes to cyclopropanols and cyclopropylamines from carboxylic acid esters and amides. See “1,n-Dicarbanionic Titanium Intermediates from Monocarbanionic Organometallics and Their Application in Organic Synthesis” by Oleg G. Kulinkovich and Armin de Meijere, p 2789. (Bottom, left) Structural model of [Cr(η6-C6H6)(CO)3] and solid model of Ein calculated for nucleophilic attack. Colorcoding of the surface: blue ) −0.15, purple ) −5.0, green ) −10.0, yellow ) −15.0, brown ) −17.0, and red ) −18.0 kcal/mol. See “Transition Metal-Mediated Dearomatization Reactions” by Andrew R. Pape, Krishna P. Kaliappan, and E. Peter Ku¨ndig, p 2917. (Bottom, right) Nucleophilic allylic, allenic, vinylic, and arylmetal compounds can be prepared through transmetalation of the related electrophilic palladium reagents with various lower-valent metal salts or alkylmetal derivatives. The methodology has been used to prepare organostannane, -silane, -samariun, -zinc, -boron, and -indium compounds which can react, in situ, with electrophiles such as aldehydes. See “Synthesis and Reactions of Allylic, Allenic, Vinylic, and Arylmetal Reagents from Halides and Esters via Transient Organopalladium Intermediates” by James A. Marshall, p 3163. In Color on the Back Cover (Top) Mechanism of the asymmetric catalytic complexation of prochiral cyclohexa-1,3-dienes by the tricarbonyliron fragment providing planar−chiral tricarbonyl (η4-cyclohexa-1,3-diene)iron complexes. See “Efficient Synthesis of Tricarbonyliron−Diene ComplexessDevelopment of an Asymmetric Catalytic Complexation” by Hans-Joachim Kno¨lker, p 2941. (Middle, left) Allenes serve as important precursors in the synthesis of highly functionalized compounds. See “Palladium-Catalyzed Reactions of Allenes” by Reinhold Zimmer, Chimmanamada U. Dinesh, Erathodiyil Nandanan, and Faiz Ahmed Khan, p 3067. Middle, right) Illustration to show the application of chiral propargyltungsten compound to the synthesis of highly functionalized and enantiopure R-methylene butyrolactones. See “Synthesis of Heterocyclic and Carbocyclic Compounds via Alkynyl, Allyl, and Propargyl Organometallics of Cyclopentadienyl Iron, Molybdenum, and Tungsten Complexes” by Chien-Le Li and Rai-Shung Liu, p 3127. (Bottom, left) Regioselective synthesis of polysubstituted benzenes was achieved by the transition metals-catalyzed reactions of unsaturated hydrocarbons such as alkynes and conjugated enynes. See “Recent Advances in the Transition Metal-Catalyzed Regioselective Approaches to Polysubstituted Benzene Derivatives” by Shinichi Saito and Yoshinori Yamamoto, p 2901. (Bottom, right) Titanocenes at work: Enantioselective electron transfer to meso-epoxides. See “Reagent-Controlled Transition-Metal-Catalyzed Radical Reactions” by Andreas Gansa¨uer and Harald Bluhm, p 2771.
