A synthetic study of Euphoreppinol via transannular cyclization reaction from a lathyrane-type skeleton

The construction of the ring system of Euphoreppinol class diterpenes was accomplished. The key step of the synthesis is a biomimetic transannular double Michael cyclization of the lathyrane skeleton. The stereochemistry of the C5 hydroxy group and the junction of the B–C ring was controlled by the conformation of the lathyrane-type precursor.