Highly asymmetric Michael additions of α,α-disubstituted aldehydes to β-nitroalkenes promoted by chiral pyrrolidine–thiourea bifunctional catalysts

A series of secondary amine–thiourea catalysts derived from l-proline and chiral diamine were prepared and first applied to the Michael addition of α,α-disubstituted aldehydes to trans-β-nitroalkenes. Moderate yields (47–75%) and excellent enantioselectivities (up to 96% ee) were obtained for a variety of aryl and heteroaryl nitroalkenes.