Alkyne Semihydrogenation with a Well-Defined Nonclassical Co–H2 Catalyst: A H2 Spin on Isomerization and E-Selectivity
摘要:
The reactivity of a co(I)-H-2 complex was extended toward the semihydrogenation of internal alkynes. Under ambient temperatures and moderate pressures of H-2, a broad scope of alkynes were semihydrogenated using a Co-I-N-2 precatalyst, resulting in the formation of trans-alkene products. Furthermore, mechanistic studies using H-1, H-2, and parahydrogen induced polarization (PHIP) transfer NMR spectroscopy revealed cis -hydrogenation of the alkyne occurs first. The Co-mediated alkene isomerization afforded the E-selective products from a broad group of alkynes with good yields and E/Z selectivity.
Regioselective CH Alkylation of Anisoles with Olefins Catalyzed by Cationic Half-Sandwich Rare Earth Alkyl Complexes
作者:Juzo Oyamada、Zhaomin Hou
DOI:10.1002/anie.201206233
日期:2012.12.14
A half sandwich helping: Cationicrare‐earthalkyl species generated from half‐sandwich rare‐earth dialkyl complexes and [Ph3C][B(C6F5)4] can serve as unique catalysts for the CHregioselectivealkylation of anisoles with alkenes. The reaction affords either ortho‐monoalkylated derivatives or products substituted at the benzylic position, depending on the substrate chosen.
半三明治有助于:由半三明治稀土二烷基配合物和[Ph 3 C] [B(C 6 F 5)4 ]生成的阳离子稀土烷基可作为CH区域选择性烷基化的独特催化剂烯烃的芳烃。根据所选择的底物,反应可提供邻-单烷基化的衍生物或在苄基位置被取代的产物。