Abnormal Aza-Baylis−Hillman Reaction of N-Tosylated Imines with Ethyl 2,3-Butadienoate and Penta-3,4-dien-2-one

[reaction: see text] The attempted aza-Baylis-Hillman reaction of N-tosylated imines with ethyl 2,3-butadienoate or penta-3,4-dien-2-one gave azetidine derivatives in the presence of DABCO. In the case of the aza-Baylis-Hillman reaction of N-tosylated imines with ethyl 2,3-butandieonate catalyzed by DMAP, novel dihydropyridine derivatives were formed.