Stereoselective Synthesis of Hexahydroimidazo[1,2-]quinolines via S2-Type Ring-Opening Hydroarylation-Hydroamination Cascade Cyclization of Activated Aziridines with -Propargylanilines.

A novel synthetic approach for the construction of 1,2,3,3a,4,5-hexahydroimidazo[1,2-]quinolines in good yields (up to 75%) with excellent stereoselectivity (dr up to 94:6, ee up to >99%) under one-pot domino ring-opening cyclization (DROC) conditions has been developed. The DROC protocol proceeds through a Lewis acid catalyzed S2-type ring-opening of activated aziridines with -propargylanilines followed by intramolecular cyclization comprising concomitant hydroarylation and hydroamination steps in a domino fashion.