Enamine chemistry. Part XXI. Condensation of L-sodium or L-ethyl prolinate with ketones to give substituted polyhydropyrrolo[1,2a]-indoles and -pyrrolizines
The effect of substituents and ring size on the cyclization of enamines derives from L-ethyl pyrrolidine-2-carboxylate and cyclic ketones, to give 1,2,3,5,6,7,8,9a-octahydropyrrolo[1,2-a]indol-9-ones, has been investigated and the conversion of the parent system into the perhydropyrrolo[1,2-a]indol-9-one is reported. Application of the reaction to simple acyclic ketones, β-diketones, and β-oxo-esters gives the corresponding substituted pyrrolizines.