已显示强硼路易斯酸三(五氟苯基)硼烷B(C 6 F 5)3从适当的供体取代的环己-1,4-二烯中提取氢化物,最终释放出二氢。该过程与亚胺和含氮杂芳基的FLP型氢化(FLP =失意的Lewis对)加氢反应相同的Lewis酸催化。最终反应是使用易于获得的环己-1,4-二烯作为还原剂,经B(C 6 F 5)3催化,即无过渡金属转移氢化。讨论了有或没有游离二氢参与的竞争反应途径。
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<sub>2</sub>
‐Symmetric Bicyclic Bisborane Catalysts: Kinetic or Thermodynamic Products of a Reversible Hydroboration of Dienes
作者:Xian‐Shuang Tu、Ning‐Ning Zeng、Ru‐Ye Li、Yu‐Quan Zhao、De‐Zhen Xie、Qian Peng、Xiao‐Chen Wang
DOI:10.1002/anie.201808289
日期:2018.11.12
C2‐symmetric bicyclic bisborane catalysts by addition reactions of internal dienes with the Piers borane, HB(C6F5)2, and an analogue, HB(p‐C6F4H)2. The dependence of the addition pattern on the reaction temperature allowed us to selectively prepare two diastereomericcatalysts from a single diene precursor. The bisboranes prepared in situ exhibited excellent activity (turnover numbers up to 200 at −40 °C)
我们通过内部二烯与Piers硼烷HB(C 6 F 5)2和类似物HB(p- C 6 F 4 H)2的加成反应制备了新型的手性C 2对称双环双硼烷催化剂。加料方式对反应温度的依赖性使我们能够从单一的二烯前体中选择性地制备两种非对映体催化剂。原位制备的双硼烷在亚胺加氢反应中表现出出色的活性(在-40°C时的转换数高达200)和对映选择性(高达95% ee)。
Direct Catalytic Access to N-Silylated Enamines from Enolizable Imines and Hydrosilanes by Base-Free Dehydrogenative SiN Coupling
作者:Julia Hermeke、Hendrik F. T. Klare、Martin Oestreich
DOI:10.1002/chem.201402866
日期:2014.7.21
α‐proton rather than α‐deprotonation of the enolizable imine followed by reaction with an electrophilic silicon reagent. The silicon electrophile, stabilized by a sulfur atom, is generated by cooperative activation of an SiH bond at the RuS bond of a tethered ruthenium(II) thiolate complex. After transfer of the silicon cation onto the imine nitrogen atom, the remaining ruthenium(II) hydride fulfills