Carbene

Abstract: Synthese, structure et caracterisation du (1,3-bis [1-adamantyl]-2,3-dihydro)-2-carbenoimidazole prepare par deprotonation du chlorure de (1,3-bis [1-adamantyl]) imidazolium

Abstract: The chemistry of heterocyclic carbenes has experienced a rapid development over the last years. In addition to the imidazolin-2-ylidenes, a large number of cyclic diaminocarbenes with different ring sizes have been described. Aside from diaminocarbenes, P-heterocyclic carbenes, and derivatives with only one, or even no heteroatom within the carbene ring are known. New methods for the synthesis of complexes with N-heterocyclic carbene ligands such as the oxidative addition or the metal atom template controlled cyclization of β-functionalized isocyanides have been developed recently. This review summarizes the new developments regarding the synthesis of N-heterocyclic carbenes and their metal complexes.

Abstract: Synthesis of Alpha-Diazocarbonyl Compounds Catalysts for Metal Carbene Transformations Insertion Reactions Intermolecular Cyclopropanation and Related Addition Reactions Intramolecular Cyclopropanation and Related Addition Reactions Cycloaddition and Substitution Reactions with Aromatic and Heteroaromatic Compounds Generation and Reactions of Ylides from Diazocarbonyl Compounds X-H Insertion Reactions of Diazocarbonyl Compounds (X = N,O,S,Se,P, Halogen) The Wolff Rearrangement and Related Reactions Reactions of Alpha-Diazocarbonyl Compounds with Aldehydes and Ketones Acid-Promoted Cyclization of Unsaturated and Aromatic Diazo Ketones Miscellaneous Diazocarbonyl Reactions Index

Abstract: [Ag(Et2-Bimy)2][AgBr2] (1; Et2-Bimy = diethylbenzimidazol-2-ylidene) was obtained readily from the reaction of [Et2-BimyH]Br with Ag2O. Compound 2, [Ag(Et2-Bimy)2]PF6, was prepared by the reaction of [Et2-Bimy]PF6 with Ag2O under basic phase transfer catalysis conditions. Both compounds 1 and 2 are good carbene transfer agents. Thus, Pd(Et2-Bimy)2Cl2, Au(Et2-Bimy)Br, and [Au(Et2-Bimy)2]PF6 were obtained in high yields using 1 and 2 as carbene sources. The byproduct AgBr or AgCl can be reused to generate 1 under basic phase transfer catalysis conditions. The crystal structure of compound 1 revealed that linear [Ag(Et2-Bimy)2]+ and [AgBr2]- groups were associated through a short AgI−AgI contact (2.956 A). FAB/mass spectrometry and molar conductivity measurements indicate the existence of ligand-unsupported AgI−AgI interactions in the gas phase and acetonitrile solution. 13C NMR studies suggest that the two Bimy ligands in 1 are fluxional in solution.