Chiral synthesis of (+)-eburnamine, (–)-eburnamenine, and (–)-eburnamonine

Abstract
The (S)-trityl-lactone (6), easily prepared from L-glutamic acid or D-mannitol, has been stereo-selectively converted into (+)-eburnamine (3), (–)-eburnamenine (4), and (–)-eburnamonine (2), via the dithiane-lactone (15).