Diels-Alder reactions of azadienophiles

While the above results have demonstrated the catalytic enantioselective aza Diels-Alder reactions of azadienes, the catalytic enantioselective aza Diels-Alder reactions of azadienophiles were reported using a chiral zirconium compound. 

Pyridines can also be constructed by the Diels-Alder reaction of azadienophiles, such as nitriles or imines, and dienes. Imines usually need to be activated with Lewis acids such as Yb(OTf)3, ZnCL, and EtzAlCl. 

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