Isothiourea-catalysed transfer hydrogenation of α,β-unsaturated para-nitrophenyl esters
作者:Jiufeng Wu、Claire M. Young、Andrew D. Smith
DOI:10.1016/j.tet.2020.131758
日期:2021.1
transfer hydrogenation of α,β-unsaturated para-nitrophenyl esters using Hantzsch ester has been developed. Good to excellent yields are observed using α,β-unsaturated aryl esters bearing electron-withdrawing β-substituents. The aryl ester products can either be isolated directly in moderate to excellent yields (7 examples, 16–98%) or converted to the corresponding methyl esters (2 examples, 68–70% yield)
Expeditious photochemical reaction toward the preparation of substituted chroman-4-ones
作者:Daniela Iguchi、Rosa Erra-Balsells、Sergio M. Bonesi
DOI:10.1016/j.tetlet.2014.06.081
日期:2014.8
photochemical preparation of 5-, 6-, and 7-substituted chroman-4-ones from aryl 3-methyl-2-butenoate esters is described. The two-phase base-catalyzed method relies upon two consecutive processes in one-pot reaction through a photo-Fries rearrangement and a based-catalyzed intramolecular oxa-Michael addition to afford the desired products.
Organocatalytic Enantioselective γ-Aminoalkylation of Unsaturated Ester: Access to Pipecolic Acid Derivatives
作者:Jianfeng Xu、Zhichao Jin、Yonggui Robin Chi
DOI:10.1021/ol402358k
日期:2013.10.4
The direct gamma-carbon functionalization of alpha,beta-unsaturated esters via N-Heterocyclic Carbene (NHC) catalysis is disclosed. This catalytically generated nucleophilic gamma-carbon undergoes highly enantioselective additions to hydrazones. The resulting delta-lactam products can be readily transformed to optically enriched pipecolic acid derivatives.