An N-heterocyclic carbene (NHC)-catalyzed chemoselective intermolecular cross-benzoin reaction of aliphatic aldehydes with isatins is developed, affording biologically important 3-substituted 3-hydroxyoxindoles (on gram scale) in moderate to good yields (46–90%). The… Click to show full abstract
An N-heterocyclic carbene (NHC)-catalyzed chemoselective intermolecular cross-benzoin reaction of aliphatic aldehydes with isatins is developed, affording biologically important 3-substituted 3-hydroxyoxindoles (on gram scale) in moderate to good yields (46–90%). The employment of a morpholinone-derived pentafluorophenyl-substituted triazolium salt as the electron-deficient NHC pre-catalyst is essential to make the reaction go through the cross-benzoin reaction pathway rather than the hydroacylation reaction pathway.
               
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