Chiral primary amine thiourea promoted highly enantioselective Michael reactions of isobutylaldehyde with maleimides

Chiral primary amine thiourea catalysts were first successfully applied to promote Michael addition of isobutyraldehyde to maleimides. A variety of N-aryl and N-aliphatic maleimides provided Michael adducts in excellent yields (up to 98%) and enantioselectivities (up to 99% ee) with 5 mol % catalyst.