Recent progress in the total synthesis of dolabellane and dolastane diterpenes

The isolation, structure and total synthesis of members of four classes of diterpenes has been summarized. Dolabellanes, neodolabellanes, dolastanes and neodolastanes are structurally related bi- or tricyclic diterpenes. Dolabellanes belong to a continuously growing class of diterpenes being isolated from marine and terrestrial sources. The published work on isolation and synthesis since 1998 has been summarized. Neodolabellanes represent a scarce class of diterpenes that have been isolated exclusively from marine sources. 5-7-6-tricyclic diterpenes classified as dolastanes have been isolated mainly from marine sources. The intense research devoted to the total synthesis of these diterpenes between 1986 and 1993 has been reviewed. Guanacastepenes have been isolated from fungi. These diterpenes are classified as neodolastanes and recently completed syntheses as well as synthetic approaches have been summarized.