Novel methodology towards the total synthesis of Pseudopterogorgia metabolites

In 1982, routine screening of the Pseudopterogorgia elizabethae stirred the scientific community by showing the presence of cytotoxic metabolites with antimicrobial activity. Since this discovery a vast amount of research has been conducted in synthesising metabolites of the soft coral. Herein we report the developments towards the synthesis of two metabolites (+)-Erogorgiaene and (+)-Elisabethadione utilising three key reactions in setting up the molecules three chiral centres. The use of asymmetric allylation, oxy-Cope rearrangement and cationic cyclisation was utilised to set up the desired stereocentres from a starting cinnamyl aldehyde. Natural elisabethadione was synthesised in a racemic form as a 2:1 mixture of diastereoisomers at the C-13 stereocentre.