Highly substituted tetrahydroimidazopyrimidine derivatives with three chiral centers have been synthesized for the first time using an organocatalytic asymmetric domino aza-Michael-Mannich reaction of α,β-unsaturated aldehydes and N-arylidene-1H-imidazol-2-amines. This efficient approach furnishes the products in good yields (42-87%) with excellent stereoselectivities (>20:1 dr, up to >99% ee).