Amidine catalysed O- to C-carboxyl transfer of heterocyclic carbonate derivatives
作者:Caroline Joannesse、Carmen Simal、Carmen Concellón、Jennifer E. Thomson、Craig D. Campbell、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1039/b805850d
日期:——
The structural requirements of amidines necessary to act as efficient O- to C-carboxyl transfer agents are delineated and the scope of this process outlined through its application to a range of oxazolyl, benzofuranyl and indolyl carbonates.
Enantioselective Organocatalytic 1,6-Addition of Azlactones to <i>para</i>-Quinone Methides: An Access to α,α-Disubstituted and β,β-Diaryl-α-amino acid Esters
作者:Wenjun Li、Xianhong Xu、Yang Liu、Hua Gao、Yuyu Cheng、Pengfei Li
DOI:10.1021/acs.orglett.8b00072
日期:2018.2.16
This work describes the first enantioselective 1,6-additions of azlactones to para-quinone methides. In the presence of a chiral phosphoric acid, 1,6-adducts were obtained in high yields (up to 96%) with excellent diastereoselectivities and enantioselectivities (all >20:1 diastereoselectivity ratio (dr), up to 99% enantiomeric excess (ee)). Importantly, the method offers a facile synthetic approach
Asymmetric trifluoromethylthiolation of azlactones under chiral phase transfer catalysis
作者:Marina Sicignano、Ricardo I. Rodríguez、Vito Capaccio、Fabio Borello、Rafael Cano、Francesco De Riccardis、Luca Bernardi、Sergio Díaz-Tendero、Giorgio Della Sala、José Alemán
DOI:10.1039/d0ob00476f
日期:——
The first enantioselective method for the installation of the SCF3 group at the C-4 position of azlactones is described in the present communication under quinidinium phasetransfercatalysis. The higher performance of substrates containing electron-rich 2-aryl groups at the azlactone was rationalized using DFT calculations.
A novel concept that conversion of chiral 2-substituted DMAP into its DMAP-N-oxide could significantly enhance the catalytic activity and still be used as an acyltransfercatalyst is presented. A new type of chiral 2-substituted DMAP-N-oxides, derived from l-prolinamides, has been rationally designed, facilely synthesized, and applied in the dynamic kinetic resolution of azlactones. Using simple MeOH
Catalytic Asymmetric Inverse‐Electron‐Demand 1,3‐Dipolar Cycloaddition of C,N‐Cyclic Azomethine Imines with Azlactones: Access to Chiral Tricyclic Tetrahydroisoquinolines
作者:Xihong Liu、Yijie Wang、Dongxu Yang、Jinlong Zhang、Dongsheng Liu、Wu Su
DOI:10.1002/anie.201602880
日期:2016.7.4
Reported herein is a bifunctional‐organocatalyst‐mediated enantioselective inverse‐electron‐demand 1,3‐dipolarcycloaddition of C,N‐cyclic azomethine imines with azlactones. The strategy provides concise access to enantioenriched C1‐substituted tetrahydroisoquinolines featuring a pyrazolidinone scaffold. Moreover, the scalability and practical utility of this protocol was well demonstrated by employing