Structural Congeners of Izenamides Responsible for Cathepsin D Inhibition: Insights from Synthesis-Derived Elucidation.

This study aimed to elucidate the structural congeners of natural izenamides A, B, and C (1-3) responsible for cathepsin D (CTSD) inhibition. Structurally modified izenamides were synthesized and biologically evaluated, and their biologically important core structures were identified. We confirmed that the natural statine (Sta) unit (3S,4S)-γ-amino-ß-hydroxy acid is a requisite core structure of izenamides for inhibition of CTSD, which is closely related to the pathophysiological roles in numerous human diseases. Interestingly, the statine-incorporated izenamide C variant (7) and 18-epi-izenamide B variant (8) exhibited more potent CTSD-inhibitory activities than natural izenamides.

S-lactoyl modification of KEAP1 by a reactive glycolytic metabolite activates NRF2 signaling.

KEAP1 (Kelch-like ECH-associated protein), a cytoplasmic repressor of the oxidative stress responsive transcription factor Nuclear factor erythroid 2-related factor 2 (NRF2), senses the presence of electrophilic agents by modification of its sensor cysteine residues. In addition to xenobiotics, several reactive metabolites have been shown to covalently modify key cysteines on KEAP1, although the full repertoire of these molecules and their respective modifications remain undefined. Here, we report the discovery of sAKZ692, a small molecule identified by high-throughput screening that stimulates NRF2 transcriptional activity in cells by inhibiting the glycolytic enzyme pyruvate kinase. sAKZ692 treatment promotes the buildup of glyceraldehyde 3-phosphate, a metabolite which leads to S-lactate modification of cysteine sensor residues of KEAP1, resulting in NRF2-dependent transcription. This work identifies a posttranslational modification of cysteine derived from a reactive central carbon metabolite and helps further define the complex relationship between metabolism and the oxidative stress-sensing machinery of the cell.

Outcomes of lipectomy in patients with advanced unilateral upper extremity lymphedema with regard to the difference in time required for indocyanine green to reach the axilla: A retrospective cohort study in a single center.

This study aimed to compare and analyze the prognosis after lipectomy with respect to the difference in time required for indocyanine green (ICG) to reach the axilla in patients with advanced unilateral upper extremity lymphedema. The study population was divided into 2 groups, according to the time required by ICG to reach the axilla after injection, that is, <1 hour (<1 hour; n = 9) and over 1 hour (>1 hour; n = 8). The patient's arm volume was examined before surgery and up to 12 months after surgery. The volume difference between the 2 groups was compared using the excess volume ratio. Statistically significant differences were not observed before surgery (P = .847) and 1 month (P = .336), 3 months (P = .630), and 6 months after surgery (P = .124) between the excess volume ratio values of the < 1 hour and > 1 hour groups. A statistically significant difference was confirmed 12 months after surgery (P = .034). The difference in the time when ICG reached the axilla in patients with lymphedema was associated with prognosis after lipectomy. The difference in time could possibly be used as a variable to classify the progress of lymphedema in the future.

Allosteric Inhibition of the Tumor-Promoting Interaction Between Exon 2-Depleted Splice Variant of Aminoacyl-Transfer RNA Synthetase-Interacting Multifunctional Protein 2 and Heat Shock Protein 70.

Although protein-protein interactions (PPIs) have emerged as an attractive therapeutic target space, the identification of chemicals that effectively inhibit PPIs remains challenging. Here, we identified through library screening a chemical probe (compound 1) that can inhibit the tumor-promoting interaction between the oncogenic factor exon 2-depleted splice variant of aminoacyl-transfer RNA synthetase-interacting multifunctional protein 2 (AIMP2-DX2) and heat shock protein 70 (HSP70). We found that compound 1 binds to the N-terminal subdomain of glutathione S-transferase (GST-N) of AIMP2-DX2, causing a direct steric clash with HSP70 and an intramolecular interaction between the N-terminal flexible region and the GST-N of AIMP2-DX2, which induces masking of the HSP70 binding region during molecular dynamics and mutation studies. Compound 1 thus interferes with the AIMP2-DX2 and HSP70 interaction and suppresses the growth of cancer cells that express high levels of AIMP2-DX2 in vitro and in preliminary in vivo experiment. This work provides an example showing that allosteric conformational changes induced by chemicals can be a way to control pathologic PPIs. SIGNIFICANCE STATEMENT: Compound 1 is a promising protein-protein interaction inhibitor between AIMP2-DX2 and HSP70 for cancer therapy by the mechanism with allosteric modulation as well as competitive binding. It seems to induce allosteric conformational change of AIMP2-DX2 proteins and direct binding clash between AIMP2-DX2 and HSP70. The compound reduced the level of AIMP2-DX2 in ubiquitin-dependent manner via suppression of binding between AIMP2-DX2 and HSP70 and suppressed the growth of cancer cells highly expressing AIMP2-DX2 in vitro and in preliminary in vivo experiment.

A Michael Acceptor Analogue, SKSI-0412, Down-Regulates Inflammation and Proliferation Factors through Suppressing Signal Transducer and Activator of Transcription 3 Signaling in IL-17A-Induced Human Keratinocyte.

The activation of signal transducer and activator of transcription 3 (STAT3), as well as up-regulation of cytokines and growth factors to promote STAT3 activation, have been found in the epidermis of psoriatic lesions. Recently, a series of synthetic compounds possessing the Michael acceptor have been reported as STAT3 inhibitors by covalently binding to cysteine of STAT3. We synthesized a Michael acceptor analog, SKSI-0412, and confirmed the binding affinity between STAT3 and SKSI-0412. We hypothesized that the SKSI-0412 can inhibit interleukin (IL)-17A-induced inflammation in keratinocytes. The introduction of IL-17A increased the phosphorylation of STAT3 in keratinocytes, whereas the inactivation of STAT3 by SKSI-0412 reduced IL-17A-induced STAT3 phosphorylation and IκBζ expression. In addition, human ß defensin-2 and S100A7, which are regulated by IκBζ, were significantly decreased with SKSI-0412 administration. We also confirmed that SKSI-0412 regulates cell proliferation, which is the major phenotype of psoriasis. Based on these results, we suggest targeting STAT3 with SKSI-0412 as a novel therapeutic strategy to regulate IL-17A-induced psoriatic inflammation in keratinocytes.

Antitumor Activity of Novel Signal Transducer and Activator of Transcription 3 Inhibitors on Retinoblastoma.

Signal transducer and activator of transcription 3 (STAT3) is a plausible therapeutic target in the treatment of retinoblastoma, the most common intraocular malignant tumor in children. STAT3, a transcription factor of several genes related to tumorigenesis, is activated in retinoblastoma tumors as well as other cancers. In this study, we investigated the structure-activity relationship of a library of STAT3 inhibitors, including a novel series of derivatives of the previously reported compound with a Michael acceptor (compound 1). We chose two novel STAT3 inhibitors, compounds 11 and 15, from the library based on their inhibitory effects on the phosphorylation and transcription activity of STAT3. These STAT3 inhibitors effectively suppressed the phosphorylation of STAT3 and inhibited the expression of STAT3-related genes CCND1, CDKN1A, BCL2, BCL2L1, BIRC5, MYC, MMP1, MMP9, and VEGFA Intraocularly administered STAT3 inhibitors decreased the degree of tumor formation in the vitreous cavity of BALB/c nude mice of an orthotopic transplantation model. It is noteworthy that compounds 11 and 15 did not induce in vitro and in vivo toxicity on retinal constituent cells and retinal tissues, respectively, despite their potent antitumor effects. We suggest that these novel STAT3 inhibitors be used in the treatment of retinoblastoma. SIGNIFICANCE STATEMENT: The current study suggests the novel STAT3 inhibitors with Michael acceptors possess antitumor activity on retinoblastoma, the most common intraocular cancer in children. Based on detailed structure-activity relationship studies, we found a 4-fluoro and 3-trifluoro analog (compound 11) and a monochloro analog (compound 15) of the parental compound (compound 1) inhibited STAT3 phosphorylation, leading to suppressed retinoblastoma in vitro and in vivo.

Discovery of novel potent migrastatic Thiazolo[5,4-b]pyridines targeting Lysyl-tRNA synthetase (KRS) for treatment of Cancer metastasis.

Recently, non-canonical roles of Lysyl-tRNA Synthetase (KRS), which is associated with cell migration and cancer metastasis, have been reported. Therefore, KRS has emerged as a promising target for the treatment of cell migration-related diseases, especially cancer metastasis, although the satisfying chemical inhibitors targeting KRS have not yet been identified. Here, we report the discovery of novel, mechanistically unique, and potent cell migration inhibitors targeting KRS, including the chemical and biological studies on the most effective N,N-dialkylthiazolo [5,4-b]pyridin-2-amine (SL-1910). SL-1910 exhibited highly potent migration inhibition (EC50 = 81 nM against the mutant KRS-overexpressed MDA-MB-231 cells) and was superior to the previously reported KRS inhibitor (migration inhibitory EC50 = 8.5 µM against H226 cells). The KRS protein binding study via fluorescence-based binding titration and KRS protein 2D-NMR mapping study, in vitro concentration-dependent cell migration inhibition, and in vivo anti-metastatic activity of SL-1910, which consists of a new scaffold, have been reported in this study. In addition, in vitro absorption, distribution, metabolism, and excretion studies and mouse pharmacokinetics experiments for SL-1910 were conducted.

Recent advances in development of hetero-bivalent kinase inhibitors.

Identifying a pharmacological agent that targets only one of more than 500 kinases present in humans is an important challenge. One potential solution to this problem is the development of bivalent kinase inhibitors, which consist of two connected fragments, each bind to a dissimilar binding site of the bisubstrate enzyme. The main advantage of bivalent (type V) kinase inhibitors is generating more interactions with target enzymes that can enhance the molecules' selectivity and affinity compared to single-site inhibitors. Earlier type V inhibitors were not suitable for the cellular environment and were mostly used in in vitro studies. However, recently developed bivalent compounds have high kinase affinity, high biological and chemical stability in vivo. This review summarized the hetero-bivalent kinase inhibitors described in the literature from 2014 to the present. We attempted to classify the molecules by serine/threonine and tyrosine kinase inhibitors, and then each target kinase and its hetero-bivalent inhibitor was assessed in depth. In addition, we discussed the analysis of advantages, limitations, and perspectives of bivalent kinase inhibitors compared with the monovalent kinase inhibitors.

ERRγ ligand HPB2 upregulates BDNF-TrkB and enhances dopaminergic neuronal phenotype.

Brain derived neurotrophic factor (BDNF) promotes maturation of dopaminergic (DAergic) neurons in the midbrain and positively regulates their maintenance and outgrowth. Therefore, understanding the mechanisms regulating the BDNF signaling pathway in DAergic neurons may help discover potential therapeutic strategies for neuropsychological disorders associated with dysregulation of DAergic neurotransmission. Because estrogen-related receptor gamma (ERRγ) is highly expressed in both the fetal nervous system and adult brains during DAergic neuronal differentiation, and it is involved in regulating the DAergic neuronal phenotype, we asked in this study whether ERRγ ligand regulates BDNF signaling and subsequent DAergic neuronal phenotype. Based on the X-ray crystal structures of the ligand binding domain of ERRγ, we designed and synthesized the ERRγ agonist, (E)-4-hydroxy-N'-(4-(phenylethynyl)benzylidene)benzohydrazide (HPB2) (Kd value, 8.35 µmol/L). HPB2 increased BDNF mRNA and protein levels, and enhanced the expression of the BDNF receptor tropomyosin receptor kinase B (TrkB) in human neuroblastoma SH-SY5Y, differentiated Lund human mesencephalic (LUHMES) cells, and primary ventral mesencephalic (VM) neurons. HPB2-induced upregulation of BDNF was attenuated by GSK5182, an antagonist of ERRγ, and siRNA-mediated ERRγ silencing. HPB2-induced activation of extracellular-signal-regulated kinase (ERK) and phosphorylation of cAMP-response element binding protein (CREB) was responsible for BDNF upregulation in SH-SY5Y cells. HPB2 enhanced the DAergic neuronal phenotype, namely upregulation of tyrosine hydroxylase (TH) and DA transporter (DAT) with neurite outgrowth, both in SH-SY5Y and primary VM neurons, which was interfered by the inhibition of BDNF-TrkB signaling, ERRγ knockdown, or blockade of ERK activation. HPB2 also upregulated BDNF and TH in the striatum and induced neurite elongation in the substantia nigra of mice brain. In conclusion, ERRγ activation regulated BDNF expression and the subsequent DAergic neuronal phenotype in neuronal cells. Our results might provide new insights into the mechanism underlying the regulation of BDNF expression, leading to novel therapeutic strategies for neuropsychological disorders associated with DAergic dysregulation.

Collective Syntheses of Guaiane Sesquiterpenes: Stereoselective Syntheses of (+)-Dysodensiol F, (+)-10ß,14-Dihydroxy-allo-aromadendrane, and (-)-Dendroside C Aglycon.

A collective synthetic route for tricyclic guaiane sesquiterpenes and total syntheses of (+)-dysodensiol F, (+)-10ß,14-dihydroxy-allo-aromadendrane, and (-)-dendroside C aglycon starting from a versatile hydroazulene intermediate were accomplished. The key features of these syntheses involve late-stage carbene-mediated diastereoselective cyclopropanation, construction of an unusual cis-fused-hydroazulene skeleton via intramolecular Dieckmann condensation, and highly stereoselective tandem conjugate addition/intramolecular allylic alkylation to afford a 5/7/3 tricyclic skeleton of guaiane natural products. The synthesis of (-)-dendroside C aglycon and the first total synthesis of (+)-dysodensiol F and (+)-10ß,14-dihydroxy-allo-aromadendrane are described in detail. Activation of the Nrf2/ARE signaling pathway by (-)-dendroside C aglycon is also disclosed via our synthesis.

An Electrophilic Deguelin Analogue Inhibits STAT3 Signaling in H-Ras-Transformed Human Mammary Epithelial Cells: The Cysteine 259 Residue as a Potential Target.

Signal transducer and activator of transcription 3 (STAT3) is a point of convergence for numerous oncogenic signals that are often constitutively activated in many cancerous or transformed cells and some stromal cells in the tumor microenvironment. Persistent STAT3 activation in malignant cells stimulates proliferation, survival, angiogenesis, invasion, and tumor-promoting inflammation. STAT3 undergoes activation through phosphorylation on tyrosine 705, which facilitates its dimerization. Dimeric STAT3 translocates to the nucleus, where it regulates the transcription of genes involved in cell proliferation, survival, etc. In the present study, a synthetic deguelin analogue SH48, discovered by virtual screening, inhibited the phosphorylation, nuclear translocation, and transcriptional activity of STAT3 in H-ras transformed human mammary epithelial MCF-10A cells (MCF10A-ras). We speculated that SH48 bearing an α,ß-unsaturated carbonyl group could interact with a thiol residue of STAT3, thereby inactivating this transcription factor. Non-electrophilic analogues of SH48 failed to inhibit STAT3 activation, lending support to the above supposition. By utilizing a biotinylated SH48, we were able to demonstrate the complex formation between SH48 and STAT3. SH48 treatment to MCF10A-ras cells induced autophagy, which was verified by staining with a fluorescent acidotropic probe, LysoTracker Red, as well as upregulating the expression of LC3II and p62. In conclusion, the electrophilic analogue of deguelin interacts with STAT3 and inhibits its activation in MCF10A-ras cells, which may account for its induction of autophagic death.

A novel small molecule STAT3 inhibitor SLSI-1216 suppresses proliferation and tumor growth of triple-negative breast cancer cells through apoptotic induction.

Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer, characterized by the lack of expression of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Owing to the absence of molecular targets, there are limited treatment options, and TNBC patients exhibit high mortality rates. Signal transducer and activator of transcription 3 (STAT3) is overexpressed and aberrantly activated in TNBC cells. Therefore, inhibition of STAT3-mediated signaling provides a potential strategy for the treatment of TNBC. In this study, A series of synthetic derivatives of SLSI-1 (a STAT3 inhibitor) were designed and evaluated for antitumor activity in TNBC cells. A novel derivative (SLSI-1216) exhibited the most potent anti-proliferative activity. SLSI-1216 effectively inhibited STAT3 activity and activation of STAT3, leading to the downregulation of AXL, a downstream target of STAT3 and epithelial-mesenchymal transition (EMT) progression. The inhibition of EMT by SLSI-1216 was associated with modulation of E-cadherin and N-cadherin. Furthermore, SLSI-1216 induced apoptosis by targeting STAT3 and effectively inhibited tumor growth in vivo. These findings suggest that SLSI-1216, as a potential inhibitor of STAT3, may be a promising therapeutic agent for TNBC.

Synthesis and Structure-Activity Relationships of Arylsulfonamides as AIMP2-DX2 Inhibitors for the Development of a Novel Anticancer Therapy.

AIMP2-DX2, a splicing variant of AIMP2, is up-regulated in lung cancer, possesses oncogenic activity, and results in tumorigenesis. Specifically inhibiting the interaction between AIMP2-DX2 and HSP70 to suppress AIMP2-DX2-dependent cancers with small molecules is considered a promising avenue for cancer therapeutics. Optimization of hit BC-DXI-04 (IC50 = 40.1 µM) provided new potent sulfonamide based AIMP2-DX2 inhibitors. Among these, BC-DXI-843 showed improved inhibition against AIMP2-DX2 (IC50 = 0.92 µM) with more than 100-fold selectivity over AIMP2 in a luciferase assay. Several binding assays indicated that this compound effectively induces cancer cell apoptosis by specifically interrupting the interaction between DX2 and HSP70, which leads to the degradation of DX2 via Siah1-mediated ubiquitination. More importantly, BC-DXI-843 demonstrated in vivo efficacy in a tumor xenograft mouse model (H460 cells) at a dosage of 50 mg/kg, suggesting it as a promising lead for development of novel therapeutics targeting AIMP2-DX2 in lung cancer.

2-Aminophenylpyrimidines as Novel Inhibitors of Aminoacyl-tRNA Synthetase Interacting Multifunctional Protein 2 (AIMP2)-DX2 for Lung Cancer Treatment.

Aminoacyl-tRNA synthetase interacting multifunctional proteins (AIMPs) have recently been considered novel therapeutic targets in several cancers. In this publication we report the development of novel 2-aminophenylpyrimidines as new AIMP2-DX2 inhibitors. In particular, aminophenylpyrimidine 3 not only exhibited promising in vitro and in vivo potency but also exerted selective inhibition of H460 and A549 cells and AIMP2-DX2 rather than WI-26 cells and AIMP2. Aminophenylpyrimidine 3 offers possible therapeutic potential in the treatment of lung cancer.

Development and Validation of Analytical Method for SH-1242 in the Rat and Mouse Plasma by Liquid Chromatography/Tandem Mass Spectrometry.

SH-1242, a novel inhibitor of heat shock protein 90 (HSP90), is a synthetic analog of deguelin: It was previously reported that the treatment of SH-1242 led to a strong suppression of hypoxia-mediated retinal neovascularization and vascular leakage in diabetic retinas by inhibiting the hypoxia-induced upregulation of expression in hypoxia-inducible factor 1α (HIF-1ɑ) and vascular endothelial growth factor (VEGF). In this study, an analytical method for the quantification of SH-1242 in biological samples from rats and mice was developed/validated for application in pharmacokinetic studies. SH-1242 and deguelin, an internal standard of the assay, in plasma samples from the rodents were extracted with methanol containing 0.1% formic acid and analyzed at m/z transition values of 368.9→151.0 and 395.0→213.0, respectively. The method was validated in terms of accuracy, precision, dilution, matrix effects, recovery, and stability and shown to comply with validation guidelines when it was used in the concentration ranges of 1-1000 ng/mL for rat plasma and of 2-1000 ng/mL for mouse plasma. SH-1242 levels in plasma samples were readily determined using the developed method for up to 480 min after the intravenous administration of 0.1 mg/kg SH-1242 to rats and for up to 120 min to mice. These findings suggested that the current method was practical and reliable for pharmacokinetic studies on SH-1242 in preclinical animal species.

15-Keto prostaglandin E2 suppresses STAT3 signaling and inhibits breast cancer cell growth and progression.

Overproduction of prostaglandin E2 (PGE2) has been linked to enhanced tumor cell proliferation, invasiveness and metastasis as well as resistance to apoptosis. 15-Keto prostaglandin E2 (15-keto PGE2), a product formed from 15-hydroxyprostaglandin dehydrogenase-catalyzed oxidation of PGE2, has recently been shown to have anti-inflammatory and anticarcinogenic activities. In this study, we observed that 15-keto PGE2 suppressed the phosphorylation, dimerization and nuclear translocation of signal transducer and activator of transcription 3 (STAT3) in human mammary epithelial cells transfected with H-ras (MCF10A-ras). 15-Keto PGE2 inhibited the migration and clonogenicity of MCF10A-ras cells. In addition, subcutaneous injection of 15-keto PGE2 attenuated xenograft tumor growth and phosphorylation of STAT3 induced by breast cancer MDA-MB-231 cells. However, a non-electrophilic analogue, 13,14-dihydro-15-keto PGE2 failed to inhibit STAT3 signaling and was unable to suppress the growth and transformation of MCF10A-ras cells. These findings suggest that the α,ß-unsaturated carbonyl moiety of 15-keto PGE2 is essential for its suppression of STAT3 signaling. We observed that the thiol reducing agent, dithiothreitol abrogated 15-keto PGE2-induced STAT3 inactivation and disrupted the direct interaction between 15-keto PGE2 and STAT3. Furthermore, a molecular docking analysis suggested that Cys251 and Cys259 residues of STAT3 could be preferential binding sites for this lipid mediator. Mass spectral analysis revealed the covalent modification of recombinant STAT3 by 15-keto PGE2 at Cys259. Taken together, thiol modification of STAT3 by 15-keto PGE2 inactivates STAT3 which may account for its suppression of breast cancer cell proliferation and progression.

Investigation of B,C-ring truncated deguelin derivatives as heat shock protein 90 (HSP90) inhibitors for use as anti-breast cancer agents.

On the basis of deguelin, a series of the B,C-ring truncated surrogates with N-substituted amide linkers were investigated as HSP90 inhibitors. The structure activity relationship of the template was studied by incorporating various substitutions on the nitrogen of the amide linker and examining their HIF-1α inhibition. Among them, compound 57 showed potent HIF-1α inhibition and cytotoxicity in triple-negative breast cancer lines in a dose-dependent manner. Compound 57 downregulated expression and phosphorylation of major client proteins of HSP90 including AKT, ERK and STAT3, indicating that its antitumor activity was derived from the inhibition of HSP90 function. The molecular modeling of 57 demonstrated that 57 bound well to the C-terminal ATP-binding pocket in the open conformation of the hHSP90 homodimer with hydrogen bonding and pi-cation interactions. Overall, compound 57 is a potential antitumor agent for triple-negative breast cancer as a HSP90 C-terminal inhibitor.

Novel Hypoxia-Inducible Factor 1α (HIF-1α) Inhibitors for Angiogenesis-Related Ocular Diseases: Discovery of a Novel Scaffold via Ring-Truncation Strategy.

Ocular diseases featuring pathologic neovascularization are the leading cause of blindness, and anti-VEGF agents have been conventionally used to treat these diseases. Recently, regulating factors upstream of VEGF, such as HIF-1α, have emerged as a desirable therapeutic approach because the use of anti-VEGF agents is currently being reconsidered due to the VEGF action as a trophic factor. Here, we report a novel scaffold discovered through the complete structure-activity relationship of ring-truncated deguelin analogs in HIF-1α inhibition. Interestingly, analog 6i possessing a 2-fluorobenzene moiety instead of a dimethoxybenzene moiety exhibited excellent HIF-1α inhibitory activity, with an IC50 value of 100 nM. In particular, the further ring-truncated analog 34f, which showed enhanced HIF-1α inhibitory activity compared to analog 2 previously reported by us, inhibited in vitro angiogenesis and effectively suppressed hypoxia-mediated retinal neovascularization. Importantly, the heteroatom-substituted benzene ring as a key structural feature of analog 34f was identified as a novel scaffold for HIF-1α inhibitors that can be used in lieu of a chromene ring.

Conformation-Enabled Total Syntheses of Ohmyungsamycins†A and B and Structural Revision of Ohmyungsamycin†B.

The first total syntheses of the bioactive cyclodepsipeptides ohmyungsamycin A and B are described. Key features of our synthesis include the concise preparation of a linear cyclization precursor that consists of N-methyl amides and non-proteinogenic amino acids, and its macrolactamization from a bent conformation. The proposed structure of ohmyungsamycin B was revised based on its synthesis. The cyclic core of the ohmyungsamycins was shown to be responsible for the excellent antituberculosis activity, and ohmyungsamycin variants with truncated chains were evaluated for their biological activity.

Total synthesis of (+)-brasilenyne via concise construction of an oxonane framework containing a 1,3-cis,cis-diene.

The enantioselective total synthesis of (+)-brasilenyne has been accomplished. The key features of the synthesis include the convergent preparation of a highly functionalized endocyclization precursor via selective epoxide opening, the construction of an oxonene skeleton through perfect regioselective Pd(0)-catalyzed endocyclization, and the installation of a 1,3-cis,cis-diene unit via a decarboxylative photophenylselenylation and site-selective selenoxide elimination sequence.