Stereoselective Synthesis ofPyrrolo[1,2-a]indolesfrom Allenes in PEG-400 as the Reaction Medium

Base-catalyzed domino cyclization of allenes with 3-chloro-2-formylindoles in PEG-400 was investigated. Pyrroloindoles were formed stereoselectively as single products. The structure of the product depends on the type of allene used. Two compounds have been characterized by single crystal X-ray diffraction.