The α-oxoketene dithioacetals undergo anionic [1, 3] cycloaddition with l, 3-diphenyl-2- azaallyllithium to give either pyrroles or spiropyrrolines with two exceptions. Lithium bromide/triethylamine induced cycloaddition of ethyl (benzylideneamino) acetate (7) with acyclic ct-oxoketene dithioacetals afforded either pyrrolidine, pyrrole or the corresponding 3- benzylideneamino-pyran-2-one derivatives depending on the reaction conditions and the ...