Asymmetric Michael addition using N-cinnamoyl- and N-crotonyl-trans-hexahydrobenzoxazolidin-2-ones

Stereoselective copper promoted conjugated additions of Grignard reagents to chiral N-enoyl amides 2 and 3 or ent-2 and ent-3 in the presence of Zn(II) salts afforded the 1,4-addition products 4-11 and the corresponding enantiomers.