Copper‐Catalyzed Ring Opening of Benzofurans and an Enantioselective Hydroamination Cascade
作者:Qing‐Feng Xu‐Xu、Qiang‐Qiang Liu、Xiao Zhang、Shu‐Li You
DOI:10.1002/anie.201809003
日期:2018.11.12
A copper(II) acetate/(R)‐DTBM‐SEGPHOS‐catalyzed ring opening of benzofurans and enantioselective hydroamination cascade with dimethoxymethylsilane (DMMS) and hydroxylamine esters is described. Starting from readily available substituted benzofurans, a series of chiral N,N‐dibenzylaminophenols, which are of high interest in pharmaceutical chemistry, were obtained with excellent enantioselectivities (up
selective and efficient reagent for the oxidation of hydroxylamines. The developed reaction conditions were shown to be compatible with the in situ trapping of the produced nitrones by a strained alkyne, via a [3 + 2] cycloaddition reaction.
photocatalytic aerobic oxidative dehydrogenation reactions of N,N-disubstituted hydroxylamines to nitrones were developed with an in situ generated photocatalyst based on commercially available 3,6-dichlorotetrazine. This process affords a wide range of nitrones in high yields under mild conditions. In addition, an oxidative (3+3) cycloaddition between an oxyallyl cation precursor and a hydroxylamine was also developed
A copper(I)-catalyzed asymmetric synthesis of P-chiral aminophosphinites with esters of hydroxylamines is achieved by means of the dynamic kinetic transformation of unsymmetrical diarylphosphines. A two-electron redox process is proposed for this reaction based on mechanistic studies.
Direct and Co-catalytic Oxidation of Hydroxylamines to Nitrones Promoted by Rhodium Nanoparticles Supported on Carbon Nanotubes
作者:Praveen Prakash、Edmond Gravel、Dinh-Vu Nguyen、Irishi N. N. Namboothiri、Eric Doris
DOI:10.1002/cctc.201601155
日期:2017.6.22
aerobic oxidation of hydroxylamines to nitrones. Two catalytic systems were developed (i.e., direct or co-catalytic) and both operated to provide high yields of the products, under mild conditions, but with their own specificity as regards the kinetics and regioselectivity of the transformation. In addition, the in situ cycloaddition of the produced nitrones with different alkynes was investigated