Development of Bifunctional Chiral Thioureas and Thiosquaramides in the Synthesis of Betti Bases.
Martyna MalinowskaAnna ZawiszaPublished in: Molecules (Basel, Switzerland) (2023)
Bifunctional thioureas and, for the first time, bifunctional thiosquaramides as organocatalysts were used in the asymmetric Betti reaction involving 1-, 2-naphthols and hydroxyquinoline with N -tosylimine and ketimine. The described methodology affords direct access to chiral aminoarylnaphthols in excellent yield (up to 98%) with high enantioselectivity (up to 80% ee) and enantioenriched 3-amino-2-oxindoles (up to 78% yield, up to 98% ee).