Synthesis of chromium N-heterocyclic carbene complexes using chromium Fischer carbenes as a source of chromium carbonyls
作者:Seongjin Kim、Soo Young Choi、Young Tak Lee、Kang Hyun Park、Helmut Sitzmann、Young Keun Chung
DOI:10.1016/j.jorganchem.2007.08.043
日期:2007.11
Chromium Fischer carbenecomplexes, [CrOMe(R)}(CO)5] have been utilized as a source of chromium carbonyls in the synthesis of chromium NHC complexes. Using the synthetic method, chromiumcomplexes of various NHC ligands were isolated in reasonable yields. Moreover, the method can be employed for the synthesis of molybdenum and tungsten NHC compounds.
Metathesis and diaziridination reactions of (CO)5W=C(OMe)-p-XC6H4 with cis-azobenzene. Electronic and solvent effects
作者:Claudia Tata Maxey、Hanadi F. Sleiman、Scott T. Massey、Lisa McElwee-White
DOI:10.1021/ja00039a029
日期:1992.6
phenyl carbenes (CO)sub 5}W=C(OMe)P-XCsub6}Hsub4} (X = H, OMe, CFsub3}) was carried out in both noncoordinating and coordinating solvents. The stability and reactivity of the initially formed zwitterionic species (CO)sub 5} WNPhNPhC(OMe)(p-XCsub6}Hsub4}) depended on the substituent X. In noncoordinating solvents, the unsubstituted zwitterionic species (CO)sub 5}WNPhNPhC(OMe)Csub6}Hsub
Enantioselective Multicomponent Synthesis of Fused 6-5 Bicyclic 2-Butenolides by a Cascade Heterobicyclisation Process
作者:Marcos G. Suero、Raquel De la Campa、Laura Torre-Fernández、Santiago García-Granda、Josefa Flórez
DOI:10.1002/chem.201102288
日期:2012.6.4
heterobicyclisation products is the result of the regioselective integration of the Grignardreagent as a propargyl fragment followed by a cascade CO/alkyne/CO insertion, ketene trapping and elimination sequence. By using lithium enolates of chiral N‐acetyl‐2‐oxazolidinones and the corresponding propargylic organocerium reagents, both enantiomers of these bicyclic heterocycles were efficiently prepared with
Carbon-carbon bond formation via carbonyl-carbene complexes
作者:K. H. Dotz
DOI:10.1351/pac198355111689
日期:1983.1.1
demonstrated upon their reactions with alkynes. Both the electrophilicity of the carbene car— hon atom and the facile substitution of carbon monoxide are used for selective carbon carbon bond formation. Nucleophilic alkynes (ynamines) add to the carbene carbon atom and then undergo insertion into the metal carbene bond. Chromium(O) is effective as a template in the annulation of carbene ligands bearing aromatic
Physical Organic Chemistry of Transition Metal Carbene Complexes. 19.<sup>1</sup> Kinetics of Reversible Alkoxide Ion Addition to Substituted (Methoxyphenylcarbene)pentacarbonylchromium(0) and (Methoxyphenylcarbene)pentacarbonyltungsten(0) in Methanol and Aqueous Acetonitrile
作者:Claude F. Bernasconi、Luis García-Río
DOI:10.1021/ja994174w
日期:2000.4.1
Rate and equilibrium constants for the nucleophilic addition of MeO- in methanol and in 90% MeCN−10% MeOH, of HC⋮CCH2O- and CF3CH2O- in 50% MeCN−50% water, and of OH- in 50% MeCN−50% water (rate constants only) to Fischer carbene complexes of the type (CO)5MC(OMe)C6H4-4-Z (M = Cr and W) are reported. The reactions lead to the formation of tetrahedral adducts of the type (CO)5M−C(OMe)(OR)C6H4-4-Z. The