A bifunctional squaramide catalyzed the enantioselective Michael addition of pyrazol-3-
ones to ortho-quinone methides, generated in situ from 2-(1-tosylalkyl)phenols is presented. The corresponding
chiral pyrazolones are obtained with good to excellent yields (27-98%) and enantiomeric excess
Keywords: Asymmetric catalysis, organocatalysis, ortho-quinone methides, pyrazolones, Michael reaction.
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