Intramolecular cyclization of allylsilyl substituted N-acyliminium ions. Access to 1- and 2-azabicyclo [X.Y.0]-alkanes. Total synthesis of (±)-mesembrine

Access to 1- and 2-azabicyclo [x.y.0] alkanes by intramolecular cyclization of allylsilanes on α-acyliminium ions is described. This methodology is also used to achieve a highly stereoselective total synthesis of (±)-mesembrine