Facile domino reactions in the statistically controlled product- and stereoselective synthesis of densely functionalized cis-1,4-cyclohexa-1,4-dienes and trans,trans-trisubstituted-1,2,5,6-tetrahydropyridines

The domino reactions of ethyl 3-oxo-4-(arylsulfonyl)butanoates with aromatic aldehydes in a 2:1 molar ratio in the presence of a catalytic amount of ammonium acetate furnished densely functionalized cyclohexa-1,4-dienes stereoselectively, while the domino reactions of ethyl 3-oxo-4-(arylsulfonyl)butanoates, aromatic aldehydes, and ammonium acetate in a 1:2:2 molar ratio afforded highly functionalized 1,2,5,6-tetrahydropyridines stereoselectively.