Taking advantage of a 6π electrocyclization–aromatization strategy, we accomplished the first and asymmetric total synthesis of rubriflordilactone B, a heptacyclic Schisandraceae bisnortriterpenoid featuring a tetrasubstituted arene moiety. The left-hand fragment was accessed through a chiral-pool-based route, and linked to the right-hand fragment by a Sonogashira coupling. The cis geometry of the electrocyclization substrates was established by hydrogenation or hydrosilylation of the alkyne. An electrocyclization–aromatization sequence finally built the multisubstituted arene. The hydrosilylation approach was of significant advantage in terms of reaction scale, reproducibility, and intermediate stability. The structure of synthetic rubriflordilactone B was validated by X-ray crystallographic analysis, and found to be consistent with that reported for the authentic natural product based on an independent X-ray crystallographic analysis. However, obvious differences in the NMR spectra of the synthetic and authentic samples suggest that the authentic samples subjected to X-ray crystallography and NMR spectroscopy were two different compounds.

The total syntheses of ileabethoxazole, pseudopteroxazole, and seco-pseudopteroxazole, three antituberculosis diterpenoids that had been isolated from Pseudopterogorgia elisabethae, were accomplished in a collective fashion. A cascade alkyne carbopalladation/Stille reaction was exploited to construct a triene precursor with suitable geometry. A fully substituted arene was then assembled through a key 6π electrocyclization/aromatization sequence, and served as an advanced common intermediate. Two radical cyclizations led to the formation of the five- and six-membered rings of ileabethoxazole and pseudopteroxazole, respectively, with the desired stereochemistry, and a straightforward side-chain elongation delivered seco-pseudopteroxazole.

Taking advantage of a 6π electrocyclization–aromatization strategy, we accomplished the first and asymmetric total synthesis of rubriflordilactone B, a heptacyclic Schisandraceae bisnortriterpenoid featuring a tetrasubstituted arene moiety. The left-hand fragment was accessed through a chiral-pool-based route, and linked to the right-hand fragment by a Sonogashira coupling. The cis geometry of the electrocyclization substrates was established by hydrogenation or hydrosilylation of the alkyne. An electrocyclization–aromatization sequence finally built the multisubstituted arene. The hydrosilylation approach was of significant advantage in terms of reaction scale, reproducibility, and intermediate stability. The structure of synthetic rubriflordilactone B was validated by X-ray crystallographic analysis, and found to be consistent with that reported for the authentic natural product based on an independent X-ray crystallographic analysis. However, obvious differences in the NMR spectra of the synthetic and authentic samples suggest that the authentic samples subjected to X-ray crystallography and NMR spectroscopy were two different compounds.

The total syntheses of ileabethoxazole, pseudopteroxazole, and seco-pseudopteroxazole, three antituberculosis diterpenoids that had been isolated from Pseudopterogorgia elisabethae, were accomplished in a collective fashion. A cascade alkyne carbopalladation/Stille reaction was exploited to construct a triene precursor with suitable geometry. A fully substituted arene was then assembled through a key 6π electrocyclization/aromatization sequence, and served as an advanced common intermediate. Two radical cyclizations led to the formation of the five- and six-membered rings of ileabethoxazole and pseudopteroxazole, respectively, with the desired stereochemistry, and a straightforward side-chain elongation delivered seco-pseudopteroxazole.

The first total synthesis of mycoleptodiscin A, a structurally unusual indolosesquiterpenoid possessing an ortho-benzoquinone motif, has been accomplished. A sulfone alkylation coupled two readily available fragments to give an aryl triene intermediate. The tetracyclic core of the molecule was assembled through a highly enantioselective iridium-catalyzed polyene cyclization. The benzylic homologation was achieved by a cationic cyanation. The indole motif was constructed via a copper-mediated intramolecular CN bond formation at a late stage.

The first total synthesis of mycoleptodiscin A, a structurally unusual indolosesquiterpenoid possessing an ortho-benzoquinone motif, has been accomplished. A sulfone alkylation coupled two readily available fragments to give an aryl triene intermediate. The tetracyclic core of the molecule was assembled through a highly enantioselective iridium-catalyzed polyene cyclization. The benzylic homologation was achieved by a cationic cyanation. The indole motif was constructed via a copper-mediated intramolecular CN bond formation at a late stage.

A unified and bioinspired oxidative cyclization strategy was used in the first total syntheses of naturally occurring 12-epi-hapalindole Q isonitrile, hapalonamide H, deschloro 12-epi-fischerindole I nitrile, and deschloro 12-epi-fischerindole W nitrile, as well as the structural revision of the latter. Hapalindoles H and Q were also synthesized.

A unified and bioinspired oxidative cyclization strategy was used in the first total syntheses of naturally occurring 12-epi-hapalindole Q isonitrile, hapalonamide H, deschloro 12-epi-fischerindole I nitrile, and deschloro 12-epi-fischerindole W nitrile, as well as the structural revision of the latter. Hapalindoles H and Q were also synthesized.

The first total synthesis of sespenine, a rare indole sesquiterpenoid from a mangrove endophyte, has been accomplished. A bioinspired aza-Prins/Friedel–Crafts/retro Friedel–Crafts cascade reaction assembles the bridged tetrahydroquinoline core. Further investigations on the aza-Prins cyclization imply that the C3 configuration of the hydroxyindolenine intermediate is crucial to the biosynthesis of sespenine and its congener xiamycin A.

The first total synthesis of sespenine, a rare indole sesquiterpenoid from a mangrove endophyte, has been accomplished. A bioinspired aza-Prins/Friedel–Crafts/retro Friedel–Crafts cascade reaction assembles the bridged tetrahydroquinoline core. Further investigations on the aza-Prins cyclization imply that the C3 configuration of the hydroxyindolenine intermediate is crucial to the biosynthesis of sespenine and its congener xiamycin A.