A diastereoselective inverse electron demand aza-Diels–Alder reaction of N-aryl-1-azadienes derived from α-amino acids is accomplished using enamine dienophiles. Activation with ytterbium triflate of these azadienes affords dimeric structures through aza-Diels–Alder reaction, where the alkene double bond of 1-azadienes also adopts the role of dienophile. An asymmetric synthesis of functionalised 1,4,5,6-tetrahydropyridine compounds derived from α-amino acids using an optically active enamine is reported.