“…A number of reviews have appeared on specialised topics, including the diterpenoids related to the labdanes, 7 the modification of neo-clerodanes, particularly with respect to salvinorin, 8,9 diterpenoids from the genus Hyptis, 10 the phytochemistry of Plectranthus barbatus, 11 the taiwaniaquinoids, 12 the icetexane diterpenoids, 13 the pseudolaric acids, 14 recent advances in the taxoids, 15 the synthesis of the cyathane diterpenoids, 16 the vibsane diterpenoids, 17 the verticillane diterpenoids, 18 and the diterpenoid alkaloids. 19 There have been an increasing number of diterpenoids that have been isolated in which one of the rings of the parent structure has been cleaved.…”