Tandem and concurrent cycloaddition/annulation reactions of chromium alkynyl carbene complexes
作者:William D. Wulff、Dominic C. Yang
DOI:10.1021/ja00336a041
日期:1984.11
La reaction de Diels-Alder des complexes α,β-acetyleniques de carbene-Cr, a lieu avec un certain nombre de dienes. Ces complexes alcynyl peuvent servir de synthons pour les esters propiolates substitues. Les cycloadditions et annelations peuvent etre realisees en tandem ou concurremment
La 反应 de Diels-Alder des complexes α,β-acetyleniques de carbene-Cr, a lieu avec un某些 nombre de dienes。Ces complexes alcynyl peuvent servir de synthons pour lesesters propiolates substitues。Les cycloadditions et annelations peuvent etre realisees en tandem ou concurremment
Highly Regioselective [3 + 2] Annulation of Azomethine Imines with 1-Alkynyl Fischer Carbene Complexes to Functionalized <i>N</i>,<i>N</i>-Bicyclic Pyrazolidin-3-ones
作者:Ning Luo、Zhaoyan Zheng、Zhengkun Yu
DOI:10.1021/ol201139w
日期:2011.7.1
The highly regioselective [3 + 2] cycloaddition of azomethine imines to 1-alkynyl Fischercarbenecomplexes has been successfully realized under mild conditions. Oxidative demetalation of the newly formed pyrazolo-pyrazolone carbenecomplexes with pyridine-N-oxide or ceric ammonium nitrate efficiently afforded pyrazolo-pyrazolone derivatives as well as cycloprop-2-enone and trisubstituted 1H-pyrazoles
New Reactivity Modes of Chromium(0) Fischer Carbene Complexes: Unprecedented Insertion of a Carbene Ligand into an Active B−H Bond
作者:Pedro Ramírez-López、Miguel A. Sierra、Mar Gómez-Gallego、María José Mancheño、Heinz Gornitzka
DOI:10.1021/om034010v
日期:2003.11.1
alkoxide extrusion followed by dimerization or oxidation. This route also justifies the reactivity of alkenyl and alkynyl alkoxy Fischercarbenecomplexes toward other boron or aluminum hydrides. Finally, when a bulky reagent such as K-Selectride is employed, the 1,2-hydride addition is disfavored and only products derived from the reduction of the C−C multiple bonds are obtained.
A new, simple access to pentacarbonyl(3-aminoallenylidene)chromium complexes
作者:Frank Stein、Michael Duetsch、Ehmke Pohl、Regine Herbst-Irmer、Armin de Meijere
DOI:10.1021/om00031a028
日期:1993.7
Primary and secondary amines react with pentacarbonyl(1-ethoxy-1-alkynylcarbene)chromium complexes 1a-g to give pentacarbonyl(3-aminoallenylidene)chromium complexes 11-18 and pentacarbonyl[ethoxy(2-aminoethenyl)carbene]chromium complexes 3-10. Crystal structures of two relevant examples are reported. The product ratio is influenced by the size of the substituent on the acetylene terminus and in the amine, the basicity of the amine, and the reaction temperature. Reaction of 1a-c,f with lithium amides gave even higher yields of the corresponding allenylidene complexes. Addition of dimethylamine to allenylidene complexes 15f and 13a gave quantitative yields of bis(dialkylamino)ethenylcarbene complexes (E/Z)-23 and (E)-24.