Amino Alcohol Catalyzed Diels-Alder Reaction of 3-Hydroxy-2-pyridones

Significance

Simple amino alcohol catalyzed enantioselective Diels-Alder reactions of both 3-hydroxy-2-pyridone and 3-hydroxy-2-­pyrone are reported. With 10 mol% aminoindanol catalyst the cycloadditions of various 4-substituted 3-hydroxy-2-pyridones with maleimides proceeded smoothly with high enantioselectivity. The reactions of 3-hydroxy-2-pyrone with other dienophiles like vinyl ketones and nitroolefins were also examined, but in the cases of β-nitrostyrenes 1,4-addition products (e.g. C) were obtained. Using the same catalyst the reaction of 3-hydroxy-2-pyrone and N-mesitylmaleimide afforded the endo-dia­stereoisomer D in 73% yield with 95:5 er.