A series of new thiourea catalysts prepared from natural amino acids have been applied in organocatalyticasymmetricMichaeladditions of α-nitrocyclohexanone to nitroalkenes. The resulting addition products are formed with excellent enantioselectivities (up to an er of 98:2) in good yields (up to 90%).
An efficient, solvent-free protocol for asymmetric Michael additions of α-nitrocyclohexanone to nitroalkenes using thiourea derivatives as hydrogen bonding catalysts has been developed. By performing the organocatalytic reactions in a planetary ballmill, high yields (up to 97%) and excellent enantioselectivities (er up to 98:2) were achieved in short reaction times with low catalyst loadings.