Stereoselective Synthesis of Amido and Phenyl Azabicyclic Derivatives via a Tandem Aza Prins-Ritter/Friedel–Crafts Type Reaction of Endocyclic <i>N</i>‑Acyliminium Ions

A simple protocol is described for the synthesis of amido and phenyl hexahydroindolizin-3­(2<i>H</i>)-one, hexahydro-1<i>H</i>-quinolizin-4­(6<i>H</i>)-one, and 1,3,4,10<i>b</i>-tetrahydropyrido­[2,1<i>-a</i>]­isoindol-6­(2<i>H</i>)-one derivatives via endo-trig (aza-Prins type) cyclization followed by an intermolecular Ritter/Friedel–Crafts reaction of cyclic <i>N</i>-acyliminium ions, which are derived from the boron trifluoride etherate treatment of regioselectively reduced <i>N</i>-homoallyl imides. The reactions are highly diastereoselective with excellent yields