Calixarene-based highly efficient primary amine-thiourea organocatalysts for asymmetric Michael addition of aldehydes to nitrostyrenes

The synthesis of calix[4]arene-based chiral bifunctional primary aminethiourea catalysts has been described from p-tert-butylcalix[4]arene for the first time. The calix[4]arene-based catalysts were successfully applied to promote Michael addition of aldehydes with nitroalkenes affording preferentially the (R)- or (S)-adducts in high yields (up to 95%) and excellent enantioselectivities (up to 99% ees).