Beilstein J. Org. Chem.2020,16, 2363–2441, doi:10.3762/bjoc.16.197
-covalentcatalysis with photoredox catalysis was reported by Rono and Knowles in 2013 (Scheme 15) [57]. They showed that using a chiral phosphoric acid (CPA), a photoredox catalyst and Hantzsch ester (HEH) as a HAT reagent, a concerted proton-coupled electron transfer (PCET) process is promoted to form
there is much progress yet to be made.
Brønsted acid catalysis
Using chiral amines and NHCs as catalysts to generate asymmetry relies upon the formation of covalently bonded intermediates such as enamines, iminium ions or Breslow intermediates within the catalytic cycle. The first example of merging non
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Graphical Abstract
Scheme 1:
Amine/photoredox-catalysed α-alkylation of aldehydes with alkyl bromides bearing electron-withdrawi...
Beilstein J. Org. Chem.2012,8, 1452–1457, doi:10.3762/bjoc.8.165
calculated VCD spectra of the reaction product 3a.
Keywords: Michael addition; non-covalentcatalysis; organocatalysis; squaramide; thiourea; Introduction
The asymmetric 1,4-conjugated addition (Michael reaction) of C-nucleophiles to enones is a powerful tool for obtaining a significant variety of
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Graphical Abstract
Figure 1:
The conjugated addition to unsaturated 1,4-diketone 1.