Total Synthesis of (−)‐Perezoperezone through an Intermolecular [5+2] Homodimerization of Hydroxy p‐Quinone

The first copper‐catalyzed intermolecular [5+2] homodimerization of hydroxy p‐quinone is presented, furnishing bicyclo[3.2.1]octadienone core structures in typically good yields and excellent diastereoselectivities. Applying this synthetic approach enables a concise nine‐step total synthesis of (?)‐perezoperezone from commercially available 3,5‐dimethoxytoluene.     

Pestaloamides A and B,two spiro-heterocyclic alkaloid epimers from the plant endophytic fungus Pestalotiopsis sp. HS30

Pestaloamides A and B(1 and 2), two novel alkaloids featuring an unprecedented spiro[imidazothiazoledione-alkylidenecyclopentenone] scaffold, were obtained from the cultures of an endophytic fungus Pestalotiopsis sp. HS30 which inhabited the stems of Isodon xerophilus. Their planar structures and absolute configurations were fully determined by extensive spectroscopic analysis and X-ray crystallography. In addition, both compounds 1 and 2 showed the latent tumor immunotherapy activity through markedly promoting the cell surface engagement of NKG2 D ligands involving MICA/B and ULBP1 in HCT116 cells.     

Structurally diverse diterpenoids from Isodon ternifolius collected from three regions

Phytochemical investigation of the aerial parts of Isodon ternifolius from three regions in Yunnan Province afforded 9 new diterpenoids, ternifoliusins A–I (1–9), together with 26 known diterpenoids. Among them, ternifoliusins A–D possess rare 6,7:8,15-diseco-7,20-olide-6,8-cyclo-ent-kaurane diterpenoid scaffold. The structures of all compounds were determined by comprehensive spectroscopic analysis, as well as quantum chemical calculation methods. Moreover, the molecular constitutions and configurations of ternifoliusins A, E, and F (1, 5, 6) were confirmed by single-crystal X-ray diffraction analysis. Ten compounds were assayed for their cytotoxic activity against the HL-60, SMMC-7721, A-549, MCF-7, and SW-480 human tumor cell lines, and compounds 13, 17, 19, 20, 31 and 34 were demonstrated to be active against all of the five human tumor cell lines.