Rhodium-Catalyzed Difunctionalization of Alkenes Using Cyclic 1,3-Dicarbonyl-Derived Iodonium Ylides

Herein, we introduce an iodonium ylide strategy to achieve novel α-alkylation of cyclic 1,3-dicarbonyls through harnessing C(sp3)–Rh species generated from 5-exo-trig cyclization to provide rapid access to molecular hybridization of medically important isoindolin-1-ones and cyclic 1,3-dicarbonyls from readily available substrates. This approach features mild conditions, good yield, excellent functional group tolerance, and the simultaneous formation of two new chemical bonds and one stereogenic center. Moreover, the hydroxyl group of resulting product provides a good handle for downstream transformations. Importantly, we also demonstrate this strategy can be achieved in a one-pot manner. A C(sp3)–Rh complex was prepared and proved to be the key intermediate

Xylaolide A, a new lactone from the fungus Xylariaceae sp. DPZ-SY43

<div><p>Chemical investigation of the fungus Xylariaceae sp. DPZ-SY43 has led to the isolation of a new compound, xylaolide A (<b>1</b>) together with three known compounds (<b>2</b>–<b>4</b>). The structures were established by analysing the spectroscopic data. Compound <b>1</b> was evaluated for its cytotoxicity.</p></div

Penixanthones A and B, two new xanthone derivatives from fungus <i>Penicillium</i> sp. SYFz-1 derived of mangrove soil sample

<p>Two new xanthone derivatives, penixanthones A (<b>1</b>) and B (<b>2</b>), together with three known compounds, aspenicillide (<b>3</b>), 1,5-dihydroxy-3-methoxy-7-methyl-anthracene-9,10-dione (<b>4</b>) and 1,2-indandiol (<b>5</b>), were isolated from the ethyl acetate extract of a culture of the fungus <i>Penicillium</i> sp. SYFz-1, which was separated from a mangrove soil sample. The structures of these compounds were elucidated by spectroscopic methods including NMR and mass spectrometry. The absolute configurations of penixanthones A (1) and B (2) were determined on the basis of electronic circular dichroism (ECD) data analysis.</p

Isochromophilones A–F, Cytotoxic Chloroazaphilones from the Marine Mangrove Endophytic Fungus <i>Diaporthe</i> sp. SCSIO 41011

Six new highly oxygenated chloroazaphilone derivatives, isochromophilones A–F (<b>1</b>–<b>6</b>), were obtained from the mangrove-derived fungus <i>Diaporthe</i> sp. SCSIO 41011, together with six known analogues (<b>7</b>–<b>12</b>). The structures of <b>1</b>–<b>6</b> including absolute configurations were determined by detailed NMR, MS spectroscopic analyses, and electronic circular dichroism spectra. Compounds <b>1</b> and <b>2</b> represent the first reported azaphilones lacking a carbonyl group at C-6. Compound <b>8</b> exhibited cytotoxic activities against three renal carcinoma cell lines, ACHN, OS-RC-2, and 786-O cells, with IC₅₀ values ranging from 3.0 to 4.4 μM, and <b>4</b> showed activity against 786-O cells with an IC₅₀ of 8.9 μM. Further studies indicated that <b>4</b> induced apoptosis in 786-O cells in a dose- and time-dependent manner

Antituberculosis compounds from a deep-sea-derived fungus <i>Aspergillus</i> sp. SCSIO Ind09F01

<p>Eleven diketopiperazine and fumiquinazoline alkaloids (<b>1–11</b>) together with a tetracyclic triterpenoid helvolic acid (<b>12</b>) were obtained from the cultures of a deep-sea derived fungus <i>Aspergillus</i> sp. SCSIO Ind09F01. The structures of these compounds (<b>1</b>–<b>12</b>) were determined mainly by the extensive NMR, ESIMS spectra data and by comparison with previously described compounds. Besides, anti-tuberculosis, cytotoxic, antibacterial, COX-2 inhibitory and antiviral activities of these compounds were evaluated. Gliotoxin (<b>3</b>), 12,13-dihydroxy-fumitremorgin C (<b>11</b>) and helvolic acid (<b>12</b>) exhibited very strong anti-tuberculosis activity towards <i>Mycobacterium tuberculosis</i> with the prominent MIC₅₀ values of <0.03, 2.41 and 0.894 μM, respectively, which was here reported for the first time. Meanwhile gliotoxin also displayed significant selective cytotoxicities against K562, A549 and Huh-7 cell lines with the IC₅₀ values of 0.191, 0.015 and 95.4 μM, respectively.</p