Cobalt Nanoparticles on Charcoal: A Versatile Catalyst in the Pauson−Khand Reaction, Hydrogenation, and the Reductive Pauson−Khand Reaction
摘要:
[GRAPHICS]Dispersions of nanometer-sized cobalt particles with very high stability were prepared in charcoal and analyzed by electron microscopy and X-ray analysis. The resulting cobalt nanoparticles on charcoal (CNC) were successfully used as a catalyst for the carbonylative cycloaddition of alkyne, alkene, and carbon monoxide (Pauson-Khand reaction), hydrogenation, and the reductive Pauson-Khand reaction.
Features and Applications of [Rh(CO)<sub>2</sub>Cl]<sub>2</sub>-Catalyzed Alkylations of Unsymmetrical Allylic Substrates
作者:Brandon L. Ashfeld、Kenneth A. Miller、Anna J. Smith、Kristy Tran、Stephen F. Martin
DOI:10.1021/jo701290b
日期:2007.11.1
A novel regio- and stereoselective [Rh(CO)2Cl]2-catalyzed allylic alkylation of unsymmetrical allylic carbonates was discovered. The regioselectivity of the reaction favors product ratios in which substitution occurs at the carbon bearing the leaving group. When an enantiomerically enriched carbonate (≥99% ee) was examined, the Rh(I)-catalyzed allylic alkylation proceeded stereoselectively to provide
Thioureas as Ligands in the Pd-Catalyzed Intramolecular Pauson−Khand Reaction
作者:Yefeng Tang、Lujiang Deng、Yangdong Zhang、Guangbin Dong、Jiahua Chen、Zhen Yang
DOI:10.1021/ol050410y
日期:2005.4.14
[reaction: see text] The thiourea-Pd complex was established as a novel type of catalyst in the PKR of allylpropargylamine, and the demonstrated chemistry may prove to be valuable for developing thiuorea as a ligand for the Pd-catalyzed Pauson-Khandreaction.
Tetramethyl Thiourea/Co<sub>2</sub>(CO)<sub>8</sub>-Catalyzed Pauson−Khand Reaction under Balloon Pressure of CO
作者:Yefeng Tang、Lujiang Deng、Yandong Zhang、Guangbin Dong、Jiahua Chen、Zhen Yang
DOI:10.1021/ol047651a
日期:2005.2.1
A Pauson-Khandtype of conversion of enynes to bicycliccyclopentenones employing the commercially available Co2(CO)8 and tetramethylthiourea (TMTU) as catalysts is described. This method allows a variety of enynes with diverse functional groups to be cyclized into cyclopentenones of interest. [reaction: see text]
Effect of Lithium Chloride on Tuning the Reactivity of Pauson-Khand Reactions Catalyzed by Palladium-Tetramethylthiourea
作者:Jia-Hua Chen、Aiwen Lei、Zhen Yang、Lu-Jiang Deng、Jing Liu、Ji-Qing Huang、Yanhe Hu、Mao Chen、Yu Lan
DOI:10.1055/s-2007-983796
日期:2007.8
A general and robust transition-metal-catalyzed Pauson-Khandreaction is still difficult to achieve. In this contribution, we describe our recent observations on the effect of lithium chloride on Pauson-Khandreactionscatalyzed by palladium(II) chloride-tetra-methylthiourea; this allows structurally diverse cyclopentenones to be prepared effectively.
作者:Yuefan Wang、Lingmin Xu、Ruocheng Yu、Jiahua Chen、Zhen Yang
DOI:10.1039/c2cc17971g
日期:——
A cobaltâTMTU complex, derived from the in situ reduction of CoBr2 with Zn in the presence of TMTU, can catalyze PausonâKhand reaction at a balloon pressure of CO, which enables the synthesis of structurally diverse cyclopentenones. This catalytic system works efficiently for both intermolecular and intramolecular PK reactions.