General synthesis of pyrroloquinolizidines: synthesis of an unnatural homologue of the pyrroloindolizidine myrmicarin alkaloid 215B.

A general synthesis approach to pyrroloquinolizidines (3,4,5,5a,6,7,8-heptahydropyrrolo[2,1,5-de]quinolizines) via a münchnone 1,3-dipolar cycloaddition is reported. The approach was applied to the synthesis of an unnatural pyrroloquinolizidine homologue of myrmicarin 215B.