A convergent and stereoselective total synthesis of (−)-crispine A, (−)-benzo[a]quinolizidine and (−)-salsolidine

A novel strategy has been developed for the syntheses of (−)-crispine, (−)-benzo[a]quinolizidine, and (−)-salsolidine using (R)-tert-butanesulfinamide as a source of chirality. The approach involves the stereoselective addition of Grignard reagent to chiral N-sulfinyl imine followed by cyclization of the secondary amide with a tethered halide as key steps.