Bench-Stable Cobalt Pre-Catalysts for Mild Hydrosilative Reduction of Tertiary Amides to Amines and Beyond
作者:Alibek Nurseiit、Jaysan Janabel、Kristina A. Gudun、Aishabibi Kassymbek、Medet Segizbayev、Tulegen M. Seilkhanov、Andrey Y. Khalimon
DOI:10.1002/cctc.201801605
日期:2019.1.23
unsaturated organic molecules, including the normally challenging reduction of amides to amines. With regard to hydrosilative reduction of amides even more effective and activator free catalytic systems can be generated from the bench‐stable, commercially available Co(acac)2 and Co(OAc)2 with dpephos and PPh3 ligands. These systems operate under mild conditions (<100 °C), with many examples of room temperature
Cobalt-Catalyzed Regiodivergent Hydrosilylation of Vinylarenes and Aliphatic Alkenes: Ligand- and Silane-Dependent Regioselectivities
作者:Chao Wang、Wei Jie Teo、Shaozhong Ge
DOI:10.1021/acscatal.6b02518
日期:2017.1.6
hydrosilylation of alkenes catalyzed by catalysts generated in situ from bench-stable Co(acac)2 and phosphine- or nitrogen-based ligands. A wide range of vinylarenes and aliphatic alkenes reacted to afford either branched (45 examples) or linear (37 examples) organosilanes in high isolated yields (average: 84%) and high regioselectivities (from 91:9 to >99:1). This transformation tolerates a variety of functional
Alkyl Grignard reagents were found to be isomerized to more stable ones in high isomerization ratios (>99%) under cooperative catalysis by iron and copper, which promote isomerization of alkyl groups and transmetalation between Fe-Mg, respectively.
NiCl2·6H2O/tBuOK, for the electrophilically activated hydrosilylation of terminal alkenes with primary silanes. This protocol provides excellent performance under mild reaction conditions: exclusive anti-Markovnikov selectivity, broad functional group tolerance (36 examples), and good scalability (TON = 5500). However, the secondary and tertiarysilanes are not suitable. Mechanistic studies revealed that
我们报告了一种简单有效的镍基催化体系NiCl 2 ·6H 2 O / t BuOK,用于末端烯烃与伯硅烷的亲电子活化氢化硅烷化。该方案在温和的反应条件下具有出色的性能:独特的抗马尔科夫尼科夫选择性,宽泛的官能团耐受性(36个示例)和良好的可扩展性(TON = 5500)。但是,仲和叔硅烷是不合适的。机理研究表明,这种均相催化的硅氢加成反应包括一种亲电子活化的Si-H键过程,而不会产生氢化镍。