Synthetic studies on clerodane diterpenoids. the total synthesis of (±)-2-oxo-5α,8α-13,14,15,16-tetranorclerod-3-en-12-oic acid

Article abstract of DOI:10.1139/v97-079

A general synthetic approach to diterpenoids of the cis-clerodane family has been developed, leading to the first total synthesis, in racemic form, of 2-oxo-5α,8α-13,14,15,16-tetranorclerod-3-en-12-oic acid (2). The key operation involved is the face-selective Diels-Alder reaction of dienone ester 10 with trans-piperylene, giving rise to adduct 11 containing the decalin nucleus and correct stereogenic centers common to many cis-clerodane diterpenoids.