Nickel-Catalyzed Borylation of Benzylic Ammonium Salts: Stereospecific Synthesis of Enantioenriched Benzylic Boronates
作者:Corey H. Basch、Kelsey M. Cobb、Mary P. Watson
DOI:10.1021/acs.orglett.5b03455
日期:2016.1.4
stereospecific, nickel-catalyzed cross-coupling of secondarybenzylic ammonium salts and diboronate esters to deliver highly enantioenriched benzylic boronates. This reaction utilizes amine-derived electrophiles, which are readily available in high enantiopurity, and simple, inexpensive nickel catalysts. This reaction has broad scope, enabling synthesis of a variety of secondarybenzylic boronates in
Cobalt-Catalyzed Asymmetric Markovnikov Hydroboration of Styrenes
作者:Xu Chen、Zhaoyang Cheng、Zhan Lu
DOI:10.1021/acscatal.8b05135
日期:2019.5.3
A cobalt-catalyzed asymmetric hydroboration of styrenes using an imidazoline phenyl picoliamide (ImPPA) ligand was first reported to deliver the valuable chiral secondary organoboronates with good functional tolerance and highenantioselectivity (up to >99% ee). This protocol is operationally simple without any activator. Particularly, this method can be applied in the asymmetric hydroboration of allylamine
An existing challenge is the development of efficient regioselective catalytic systems that are compatible with stable hydroboration reagents and can be rendered enantioselective by the use of nonracemic ligands. Copper(I) complexes with chelating phosphines catalyzed the regio‐ and enantioselective hydroboration of styrenes with pinacolborane (PinBH) at room temperature to afford the corresponding
Asymmetric synthesis<i>via</i>stereospecific C–N and C–O bond activation of alkyl amine and alcohol derivatives
作者:Sarah M. Pound、Mary P. Watson
DOI:10.1039/c8cc07093h
日期:——
electrophiles for stereospecific, nickel-catalyzed cross-coupling reactions, as well as the prior art that inspired our efforts. The success of our effort has relied on the use of benzyl ammonium triflates as electrophiles for cross-couplings via C–Nbondactivation and benzylic and allylic carboxylates for cross-couplings via C–O bondactivation. Our work, along with others’ exciting discoveries, has demonstrated
Nickel-Catalyzed Enantioselective Hydroboration of Vinylarenes
作者:Hai N. Tran、Levi M. Stanley
DOI:10.1021/acs.orglett.1c04073
日期:2022.1.14
The enantioselective hydroboration of vinylarenes catalyzed by a chiral, nonracemic nickel catalyst is presented as a facile method for generating chiral benzylic boronate esters. Various vinylarenes react with bis(pinacolato)diboron (B2pin2) in the presence of MeOH as a hydride source to form chiral boronate esters in up to 92% yield with up to 94% ee. The use of anhydrous Me4NF to activate B2pin2
由手性非外消旋镍催化剂催化的乙烯基芳烃的对映选择性硼氢化反应是一种生成手性苯甲基硼酸酯的简便方法。在作为氢化物源的 MeOH 存在下,各种乙烯基芳烃与双(频哪醇)二硼(B 2 pin 2)反应形成手性硼酸酯,产率高达 92%,ee 高达 94%。使用无水 Me 4 NF 激活 B 2 pin 2对于确保快速金属转移以实现高对映选择性至关重要。