Investigations into the reactions of imines and enamines.

Abstract

Recent work in our laboratory has led to a new synthesis of the 2-oxo-a8'&-hexahydroquinoline ring system. This involved the condensation of B-alkylaminopropanoates with 2-methylcyclohexanone. Further reactions of B-aminopropanoates with other cyclic ketones and acyclic ketones have been investigated and are now reported. These reactions are found to be sensitive to steric effects, the stability of the ketone and the presence of molecular sieves and have led not only to the synthesis of the quinolone ring system but also to the inden-7-one and pyridone ring systems. A new one pot synthesis of the bicyclo[2.2.2]octan-5-one ring system from acyclic precursors has recently been reported. Reaction of" two equivalents of phenyl vinyl ketone with one equivalent of N-2-butylidenebenzylamine has lead to the synthesis of 2-benzoyl-4-methyl-l-phenylbicyclo[2.2.2]octan-5one as a mixture of two isomers. This reaction has now been extended to N-2-(4-phenylbutylidene)propylamine and ethyl N-propyl-4-iminopentanoate and our findings are reported.