An efficient synthesis of substituted spiro[isoxazolopyrroloisoquinolines] via diastereoselective N-acyliminium ion cyclization

Abstract A simple and efficient strategy was developed for the synthesis of fused pyrrolo[2,1- a ]isoquinoline ring systems. The 5- and 6-substituted isoxazolopyrroloisoquinolines were readily prepared via diastereoselective N -acyliminium ion cyclization of 5-(1- R (or 2- R )-substituted-2-phenylethyl)-6-hydroxytetrahydro-4 H -pyrrolo[3,4- d ]isoxazol-4-ones derived from the corresponding bicyclic dihydroisoxazoles.