Studies towards the synthesis of guanidine alkaloids; synthesis of a tricyclic guanidine from succinimide

Abstract The synthesis of a tricyclic guanidine as a model compound for ptilomycalin A and related guanidine alkaloids is described. The synthesis starts from succinimide and features an N -acyliminium ion coupling, an Eschenmoser sulfide-contraction and an N -guanylation as the key steps.