Catalyst-Controlled Regioselectivity in the Synthesis of Branched Conjugated Dienes via Aerobic Oxidative Heck Reactions

Pd-catalyzed aerobic oxidative coupling of vinylboronic acids and electronically unbiased alkyl olefins provides regioselective access to 1,3-disubstituted conjugated dienes. Catalyst-controlled regioselectivity is achieved by using 2,9-dimethylphenanthroline as a ligand. The observed regioselectivity is opposite to that observed from a traditional (nonoxidative) Heck reaction between a vinyl bromide and an alkene. DFT computational studies reveal that steric effects of the 2,9-dimethylphenanthroline ligand promote C–C bond formation at the internal position of the alkene

Divergent Total Syntheses of (−)-Lycopladine D, (+)-Fawcettidine, and (+)-Lycoposerramine Q

Enantioselective total syntheses of (+)-fawcettidine and (+)-lycoposerramine Q as well as the first total synthesis of (−)-lycopladine D from a common intermediate have been accomplished by a divergent path. The common intermediate was derived from a Hajos–Parrish-like diketone by a stereoselective Birch reduction and a Suzuki coupling. The synthesis of (−)-lycopladine D featured an allylic oxidation and a biomimetic aminoketalization while the route to (+)-fawcettidine and (+)-lycoposerramine Q highlighted an oxidative rearrangement

Xanthone Glucosides: Isolation, Bioactivity and Synthesis

Xanthones are secondary metabolites found in plants, fungi, lichens, and bacteria from a variety of families and genera, with the majority found in the Gentianaceae, Polygalaceae, and Clusiaceae. They have a diverse range of bioactivities, including anti-oxidant, anti-bacterial, anti-malarial, anti-tuberculosis, and cytotoxic properties. Xanthone glucosides are a significant branch of xanthones. After glycosylation, xanthones may have improved characteristics (such as solubility and pharmacological activity). Currently, no critical review of xanthone glucosides has been published. A literature survey including reports of naturally occurring xanthone glucosides is included in this review. The isolation, structure, bioactivity, and synthesis of these compounds were all explored in depth

The Protective Effects and Potential Mechanisms of Ligusticum chuanxiong: Focus on Anti-Inflammatory, Antioxidant, and Antiapoptotic Activities

Ligusticum chuanxiong (LC) is a Chinese materia medica which is widely used in clinical settings to treat headaches, blood extravasation, and arthritis. Recent studies demonstrate that LC possesses versatile pharmacological functions, including antiatherosclerosis, antimigraine, antiaging, and anticancer properties. Moreover, LC also shows protective effects in the progression of different diseases that damage somatic cells. Oxidative stress and inflammation, which can induce somatic cell apoptosis, are the main factors associated with an abundance of diseases, whose progresses can be reversed by LC. In order to comprehensively review the molecular mechanisms associated with the protective effects of LC, we collected and integrated all its related studies on the anti-inflammatory, antioxidant, and antiapoptotic effects. The results show that LC could exhibit the mentioned biological activities by modulating several signaling pathways, specifically the NF-κB, Nrf2, protein kinase, and caspase-3 pathways. In future investigations, the pharmacokinetic properties of bioactive compounds in LC and the signaling pathway modulation of LC could be focused

Bifunctional Quaternary Ammonium Salts Catalyzed Stereoselective Conjugate Addition of Oxindoles to Electron-Deficient β‑Haloalkenes

A highly <i>Z</i>-selective asymmetric conjugate addition of 3-substituted oxindoles to β-haloalkene ketones/esters catalyzed by readily available chiral bifunctional quaternary ammonium salts is reported. This reaction provides efficient access to a range of 2-oxoindole derivatives bearing a thermodynamically unstable <i>Z</i>-olefin structure and a chiral quaternary carbon center in high yields (up to 90%) and with good to high stereoselectivities (up to >19:1 <i>Z</i>/<i>E</i> and 91% ee) under mild conditions

Bifunctional Quaternary Ammonium Salts Catalyzed Stereoselective Conjugate Addition of Oxindoles to Electron-Deficient β‑Haloalkenes

A highly <i>Z</i>-selective asymmetric conjugate addition of 3-substituted oxindoles to β-haloalkene ketones/esters catalyzed by readily available chiral bifunctional quaternary ammonium salts is reported. This reaction provides efficient access to a range of 2-oxoindole derivatives bearing a thermodynamically unstable <i>Z</i>-olefin structure and a chiral quaternary carbon center in high yields (up to 90%) and with good to high stereoselectivities (up to >19:1 <i>Z</i>/<i>E</i> and 91% ee) under mild conditions

Divergent Total Syntheses of (−)-Lycopladine D, (+)-Fawcettidine, and (+)-Lycoposerramine Q

Enantioselective total syntheses of (+)-fawcettidine and (+)-lycoposerramine Q as well as the first total synthesis of (−)-lycopladine D from a common intermediate have been accomplished by a divergent path. The common intermediate was derived from a Hajos–Parrish-like diketone by a stereoselective Birch reduction and a Suzuki coupling. The synthesis of (−)-lycopladine D featured an allylic oxidation and a biomimetic aminoketalization while the route to (+)-fawcettidine and (+)-lycoposerramine Q highlighted an oxidative rearrangement

Enantioselective Total Synthesis of (−)-Maoecrystal V

The enantioselective synthesis of maoecrystal V, a cytotoxic polycyclic diterpene, is described. Key reactions in the synthesis include an intramolecular Heck reaction, an oxidative cycloetherification, and an intermolecular Diels–Alder reaction to forge the carbocyclic core in a concise and stereoselective manner. Late-stage amine and C–H oxidation is used to install the final functional groups required to complete the synthesis

Copper-Catalyzed Direct Asymmetric Vinylogous Mannich Reaction between β,γ-Alkynyl-α-ketimino Esters and β,γ-Unsaturated <i>N</i>‑Acylpyrazoles

We report a Cu(I)–Ph-BPE-catalyzed asymmetric vinylogous Mannich reaction of β,γ-alkynyl-α-ketimino esters with β,γ-unsaturated N-acylpyrazoles. In this process, the Cu(I)–Ph-BPE catalyst activates the β,γ-alkynyl-α-ketimino ester through N,O-coordination, enabling the subsequent nucleophilic addition of a dienolate generated from the β,γ-unsaturated N-acylpyrazole via α-position deprotonation with a catalytic amount of tertiary amine. The reactions gave useful products with very high enantioselectivities. A broad range of substrates with various substituents are tolerated in this reaction. The versatility of this method was demonstrated by a gram-scale reaction, and subsequent elaboration of the Mannich adducts was also provided

Potential pathological mechanisms and pharmacological interventions for cadmium-induced miscarriage

The prevalence of cadmium (Cd) contamination has emerged as a significant global concern. Exposure to Cd during pregnancy is associated with adverse pregnancy outcomes, including miscarriage. However, there is currently a lack of comprehensive summaries on Cd-induced miscarriage. Therefore, it is imperative to further strengthen research into in vivo studies, clinical status, pathological mechanisms, and pharmacological interventions for Cd-induced miscarriage. This study systematically presents the current knowledge on animal models and clinical trials investigating Cd exposure-induced miscarriage. The underlying mechanisms involving oxidative stress, inflammation, endocrine disruption, and placental dysfunction caused by Cd-induced miscarriage are also extensively discussed. Additionally, potential drug interventions such as melatonin, vitamin C, and vitamin E are highlighted for their pharmacological role in mitigating adverse pregnancy outcomes induced by Cd