Exploiting the enantioselectivity of Baeyer-Villiger monooxygenases via boron oxidation
摘要:
The enantioselective carbon-boron bond oxidation of several chiral boron-containing compounds by Baeyer-Villiger monooxygenases was evaluated. PAMO and M446G PAMO conveniently oxidized 1-phenylethyl boronate into the corresponding 1-(phenyl)ethanol (ee = 82-91%). Cyclopropyl boronic esters were also oxidized but with no enantioselectivity. beta-Boryl carboxylic esters were not oxidized by any BVMOs. (C) 2012 Elsevier Ltd. All rights reserved.
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
The pinacol of ligands: The (R)‐DTBM‐Segphos coordinated copper(I) complex was found to be very effective for the asymmetrichydroboration of β‐substituted styrene derivatives with pinacolborane (see scheme; DTBM=3,5‐di‐tert‐butyl‐4‐methoxyphenyl). This new method affords benzylic pinacol boronate esters with excellent levels of regio‐ and enantioselectivity (>99 %).
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