Asymmetric Hetero-Diels-Alder Reaction of Danishefsky's Diene with α-Ketoesters and Isatins Catalyzed by a Chiral N,N′-Dioxide/Magnesium(II) Complex

A highly enantioselective hetero-Diels-Alder reaction of Danishefsky's diene with -ketoesters and isatins has been realized by using a chiral N,N-dioxide/Mg-II complex. In the presence of only 0.1-0.5mol% catalyst, a series of substrates were transformed into the corresponding tetrasubstituted 2,3-dihydropyran-4-ones in up to 99% yield and more than 99%ee in two hours.