Enantioselective Synthesis of (+)-Isobretonin A.

An enantioselective synthesis of (+)-isobretonin A is described. The chiral glycerol moiety was enantioselectively prepared by reduction of an optically active beta-keto sulfoxide. The all-trans trienic part of the molecule was stereoselectively synthesized via reductive elimination of a 1,6-dibenzoate 2,4-diene with sodium amalgam.