38453-72-4Relevant articles and documents
Z-E photoisomerization of benzylidenebenzocyclobutenones via ketene- allene intermediates. A laser flash photolysis study
Boch,Bradley,Durst,Scaiano
, p. 19 - 22 (1994)
Benzylidenebenzocyclobutenones I-E and I-Z undergo photoinduced isomerization via the intermediacy of ketene-allene II which in acetonitrile has a lifetime of ~26 μs and can be trapped with water and methanol. Trapping by the latter occurs with a rate constant of 1.2 x 104 M-1 s-1 and leads to the expected ester. In addition to Z = E isomerization, product studies reveal the formation of dimeric products in very low quantum yields.
Catalytic Chemoselective and Stereoselective Semihydrogenation of Alkynes to E-Alkenes Using the Combination of Pd Catalyst and ZnI2
Maazaoui, Radhouan,Abderrahim, Raoudha,Chemla, Fabrice,Ferreira, Franck,Perez-Luna, Alejandro,Jackowski, Olivier
supporting information, p. 7544 - 7549 (2019/01/03)
An efficient E-selective semihydrogenation of internal alkynes was developed under low dihydrogen pressure and low reaction temperature from commercially available reagents: Cl2Pd(PPh3)2, Zn0, and ZnI2. Kinetic studies and control experiments underline the significant role of ZnI2 in this process under H2 atmosphere, establishing that the transformation involves syn-hydrogenation followed by isomerization. This simple and easy-to-handle system provides a route to E-alkenes under mild conditions.
Encaging palladium(0) in layered double hydroxide: A sustainable catalyst for solvent-free and ligand-free Heck reaction in a ball mill
Shi, Wei,Yu, Jingbo,Jiang, Zhijiang,Shao, Qiaoling,Su, Weike
supporting information, p. 1661 - 1668 (2017/09/27)
In this paper, the synthesis of a cheap, reusable and ligand-free Pd catalyst supported on MgAl layered double hydroxides (Pd/MgAl-LDHs) by co-precipitation and reduction methods is described. The catalyst was used in Heck reactions under highspeed ball milling (HSBM) conditions at room temperature. The effects of milling-ball size, milling-ball filling degree, reaction time, rotation speed and grinding auxiliary category, which would influence the yields of mechanochemical Heck reactions, were investigated in detail. The characterization results of XRD, ICP-MS and XPS suggest that Pd/MgAl-LDHs have excellent textural properties with zero-valence Pd on its layers. The reaction results indicate that the catalyst could be utilized in HSBM systems to afford a wide range of Heck coupling products in satisfactory yields. Furthermore, this catalyst could be easily recovered and reused for at least five times without significant loss of catalytic activity.