Synthesis of Halogenated Cyclic Enamines from Cyclic N‐ 2‐En‐4‐ynyl‐ N ‐1‐ynylamides and N ‐Propargyl‐ N ‐1‐ynylamides via a Tandem Iron Halide Promoted N‐to‐C Shift‐Aza‐Prins Cyclization Sequence

The Aza-Prins Reaction of 1,2-Dicarbonyl Compounds with 3-Vinyltetrahydroquinolines: Application to the Synthesis of Polycyclic Spirooxindole Derivatives

The aza-Prins reaction of 6,7-dimethoxy-3-vinyl-1,2,3,4-tetrahydroquinoline (1) with 1,2-dicarbonyl compounds proceeded smoothly in the presence of HCl, and the corresponding tricyclic benzazocines were isolated in yields of 20-86%. The reaction proceeded in a stereoselective manner, and the formation of the 2,4-trans isomer was observed. The reaction of 1 with an enantiopure ketoester gave the corresponding tricyclic benzazocine as a mixture of diastereomers. The diastereomers were easily separated and converted to enantiopure tricyclic benzazocines. The synthesis of spirooxindole derivatives was achieved by the reaction of 1 with isatin derivatives.