A pair of novel enantiomeric polyketide dimers, (+)- and (−)-ascomlactone A (1a and 1b), were obtained from a mangrove endophytic fungus Ascomycota sp. SK2YWS-L. The structures were elucidated based on spectroscopic methods, and the absolute configurations were determined by X-ray diffraction and electronic circular dichroism (ECD) calculations. Ascomlactone A possessed an unprecedented polymerization system, which constructed an unusual nine-membered lactone ring between the monomers. A possible biogenetic pathway was proposed. Both 1a and 1b exhibited significant inhibitory effects against α-glucosidase with IC50 values of 63.7 and 27.9 μM, respectively. A further docking study provided an inside perspective of the action in α-glucosidase.

Two new chlorinated preussomerins, chloropreussomerins A and B (1 and 2), together with nine known preussomerin analogues, 3–11, were obtained from the endophytic fungus Lasiodiplodia theobromae ZJ-HQ1. Their structures were elucidated by a combination of spectroscopic analyses. The absolute configurations of 1 and 2 were both determined by single-crystal X-ray diffraction using Cu Kα radiation. Chloropreussomerins A and B (1 and 2) are the first chlorinated compounds in the preussomerin family, and preussomerin M (3) is reported for the first time as a natural product. Compounds 1 and 2 showed potent in vitro cytotoxicity against A549 and MCF-7 human cancer cell lines, with IC50 values ranging from 5.9 to 8.9 μM, and compounds 4–7 exhibited significant bioactivity against A549, HepG2, and MCF-7 human cancer cell lines, with IC50 values of 2.5–9.4 μM. In the antibacterial assay, compounds 1, 2, 5–7, and 11 exhibited significant activities against Staphylococcus aureus, with MIC values between 1.6 and 13 μg/mL.

Iridium-catalyzed asymmetric ring-opening reaction of \(N\)-substituted azabenzonorbornadienes with various carboxylic acids has been developed. The ring-opening reaction offered trans-1,2-dihydronaphthalene products containing an allylic carboxylate moiety in moderate yields (up to 89 %) with high enantioselectivities (up to 96 %). The trans-configuration of the products was confirmed by X-ray crystallography.

Asperterpenol A (1) and asperterpenol B (2), two novel sesterterpenoids with an unusual 5/8/6/6 tetracyclic ring skeleton, were isolated from a mangrove endophytic fungus Aspergillus sp. 085242. The structures were elucidated on the basis of spectroscopic methods and the absolute configurations determined by single-crystal X-ray diffraction analysis. Compounds 1 and 2 inhibit acetylcholinesterase with IC50 values of 2.3 and 3.0 μM, respectively.

Asperterpenoid A (1), a novel sesterterpenoid with a new carbon skeleton, has been isolated from a mangrove endophytic fungus Aspergillus sp. 16-5c. Its structure was characterized by extensive spectroscopic methods, and the absolute configuration was determined by single crystal X-ray diffraction analysis. Asperterpenoid A (1) exhibited strong inhibitory activity against Mycobacterium tuberculosis protein tyrosine phosphatase B (mPTPB) with an IC50 value of 2.2 μM.

We have explored a new iridium-catalyzed ring-opening reaction of oxabenzonorbornadienes with a variety of primary aromatic amine or N-substituted piperazine nucleophiles, affording the corresponding products in excellent yields (up to 99%) with moderate enantioselectivity (25−81% ee). The trans configuration of product 2d was confirmed by X-ray crystallography.

A novel iridium-catalyzed ring-opening reaction of azabicyclic alkenes with a variety of primary aromatic amines is reported, which afforded the corresponding 1,2-trans-diamine derivatives in high yields (up to 96%) with excellent enantioselectivities (up to 97% ee) under relatively mild conditions. The trans configuration of product 2b was confirmed by X-ray crystallography.