Total synthesis of (-)-20-epiuleine via stereocontrolled one-pot asymmetric azaelectrocyclization followed by novel 1,4-addition reaction.

The first asymmetric total synthesis of an indole alkaloid, (-)-20-epiuleine, containing the 2,3,4-trisubstituted piperidine core, was achieved using a stereocontrolled one-pot asymmetric 6π-azaelectrocyclization followed by a stereoselective 1,4-addition reaction of the unsaturated ester with a Grignard reagent resulting from the novel neighboring participation of the hydroxyl group in cis-aminoindanol as a chiral nitrogen source.