In this article, we describe our efforts on the total synthesis of bolivianine (1) and isobolivianine (2), involving the synthesis of onoseriolide (3). The first generation synthesis of bolivianine was completed in 21 steps by following a chiral resolution strategy. Based on the potential biogenetic relationship between bolivianine (1), onoseriolide (3), and β-(E)-ocimene (8), the second generation synthesis of bolivianine was biomimetically achieved from commercially available (+)-verbenone in 14 steps. The improved total synthesis features an unprecedented palladium-catalyzed intramolecular cyclopropanation through an allylic metal carbene, for the construction of the ABC tricyclic system, and a Diels-Alder/intramolecular hetero-Diels-Alder (DA/IMHDA) cascade for installation of the EFG tricyclic skeleton with the correct stereochemistry. Transformation from bolivianine to isobolivianine was facilitated in the presence of acid. The biosynthetic mechanism and the excellent regio- and endo selectivities in the cascade are well supported by theoretical chemistry based on the DFT calculations.

Convergent total synthesis of crotophorbolone was accomplished in 18 longest linear steps. Observation of unexpected thermodynamic stability of a cis,trans-5/7/6 tricycle would benefit synthetic design of tigliane- and daphnane-related diterpenoids.

An asymmetric synthesis strategy of the fully functionalized six-membered ring of trigoxyphin A, a daphnane-type diterpenoid, has been accomplished concisely from a d-tartrate derivative. Key elements of this synthesis involve the tandem ozonization/intramolecular HWE reaction to construct the α,β-unsaturated cyclohexenone skeleton, the radical cyclization to introduce the C8 chirality and sequential Kumada cross-coupling/hydroboration-oxidation to introduce the C11 chirality. The target substructure could be synthetically achieved on a multi-gram scale.