Total synthesis of (3R,5R) and (3R,5S)-sonnerlactones

In this Letter, an enantioselective synthesis of (3R,5R)-sonnerlactone and (3R,5S)-sonnerlactone have been described. Stereochemistry at C-5 position was fixed using a suitable proline catalyzed reaction during the synthesis of aliphatic segment. To accomplish this target, Mitsunobu reaction for inversion of a stereo-centre and ring-closing metathesis (RCM) for macrocyclic ring formations have been applied as key transformations.120