Asymmetric Michael Addition of Arylthiols to (alpha),(beta)-Unsaturated Carbonyl Compounds Catalyzed by Bifunctional Organocatalysts

Bifunctional chiral organocatalysts comprising thiourea and tertiary amine groups were synthesized. They act as efficient catalysts for asymmetric Michael addition of arylthiols to (alpha),(beta)-unsaturated carbonyl compounds. Enantioselectivity up to 85% has been achieved. Asymmetric (alpha)-protonation reaction (up to 60% ee) can be obtained in the presence of the bifunctional catalyst.