... Please enable JavaScript to use all the features on this page. Tetrahedron. Volume 61, Issue 4, 24 January 2005, Pages 977–1003. Cover image Cover image. Synthesis of tri- and tetracyclic diterpenes. Cyclisations promoted by SmI 2. ... (i) OsO4, NMO, tBuOH/THF/H2O, rt, 18h; (ii) LTA, benzene, rt, 2h; (iii) ... Scheme 2. (i) OsO 4 , NMO, t BuOH/THF/H 2 O, rt, 18 h; (ii) LTA, benzene, rt, 2 h; (iii) H 2 /PtO 2 /Et 2 O, rt, 36 h for 3 to 4 and 10 h for 3 to 7 and 8; (iv) DIBAL-H ...