Double and iterative asymmetric dihydroxylation (AD) on achiral substrates with two prochiral centers (terminal olefins) caused an enantiomeric enhancement and its synthetic application to C₂ symmetric azacycloalkanes and 2,6-disubstituted piperidines is described.  Repeated AD reaction for terminal olefins also improved stereoselectivity (ee) and a number of asymmetric syntheses of alkaloids are demonstrated.