Stabilised arylzinc iodide, prepared by direct insertion of zinc into aryl iodides, were used as nucleophiles in the Hayashi Rh‐catalysed enantioselective conjugateaddition to enones. The reaction conditions were optimized in the addition of phenylzinc iodide to 2‐cyclohexen‐1‐one, obtaining good yields and 99% ee of the addition product. The general applicability of the protocol was checked using
Enantioselective β-C(sp<sup>3</sup>)–H arylation of amides<i>via</i>synergistic nickel and photoredox catalysis
作者:Wu Zhang、Xiaomin Shu、Leitao Huan、Buqing Cheng、Haohua Huo
DOI:10.1039/d1ob01774h
日期:——
An enantioselective benzylic β-C(sp3)–Harylation of amides via synergistic nickel and photoredoxcatalysis is reported. The C–H bond is activated by a bromine-radical-mediated C–H cleavage. This mild yet straightforward protocol provides arylation products in up to 96% yield and with up to 95% ee.
Evaluation of Palladacycles as a Non-Rhodium Based Alternative for the Asymmetric Conjugate 1,4-Addition of Arylboronic Acids to α,β-Unsaturated Enones
作者:Jonathan Wong、Kennard Gan、Houguang Jeremy Chen、Sumod A. Pullarkat
DOI:10.1002/adsc.201400473
日期:2014.11.3
AbstractThe asymmetric conjugate 1,4‐addition of arylboronic acids to α,β‐unsaturated carbonyl compounds is an extremely versatile and widely used organic transformation. While the rhodium(I)‐catalysed reaction has been thoroughly explored, the asymmetric palladium‐catalysed protocol is far less developed and understood, particularly with acyclic enones as substrates. Herein, we report the systematic evaluation of a series of metallacycles for this reaction and the conjugate addition of arylboronic acids to a wide range of α,β‐unsaturated enones, catalysed by an easily accessible and robust chiral phosphapalladacycle in high yields and enantioselectivities.magnified image
A first high enantiocontrol of an asymmetric tertiary carbon center attached with a fluoroalkyl group via Rh(I)-catalyzed conjugate addition reaction
Treatment of fluoroalkylated electron-deficient olefins with various boronic acids in the presence of a catalytic amount of Rh(l) coordinated with (S)-BINAP in toluene/H2O at the reflux temperature for 3 h gave the corresponding conjugate addition products with high enantioselectivity in high yields. (C) 2008 Elsevier Ltd. All rights reserved.
Rh/chiral sulfinylphosphine catalyzed asymmetric 1,4-addition of arylboronic acids to chalcones
作者:Guihua Chen、Junwei Xing、Peng Cao、Jian Liao
DOI:10.1016/j.tet.2012.04.096
日期:2012.7
A general method to obtain enantioenriched 1,3,3-triarylpropan-1-ones bearing a diarylmethine stereocenter was developed using Rh/chiral sulfinylphosphine catalyzed 1,4-addition of arylboronic acids to chalcones. The catalysis progressed smoothly in the presence of 2 mol % catalyst formed in situ from [Rh(C2H4)(2)Cl](2) and chiral tert-butanesulfinylphosphine and gave the adducts with up to 99% yield and 98% ee. (C) 2012 Elsevier Ltd. All rights reserved.