Chemical and Toxicological Investigations of a Previously Unknown Poisonous European Mushroom Tricholoma terreum

The established tradition of consuming and marketing wild mushrooms has focused attention on mycotoxicity, which has become a global issue. In the present study, we describe the toxins found in a previously unknown poisonous European mushroom Tricholoma terreum. Fifteen new triterpenoids terreolides A–F ( 1 – 6 ) and saponaceolides H–P ( 8 – 16 ) were isolated from the fruiting bodies of the toxic mushroom T. terreum. Terreolides A–C ( 1 – 3 ) possessed a unique 5/6/7 trioxaspiroketal system, whereas terreolides D–F ( 4 – 6 ) possessed an unprecedented carbon skeleton. Two abundant compounds in the mushroom, saponaceolide B ( 7 ) and saponaceolide M ( 13 ), displayed acute toxicity, with LD₅₀ values of 88.3 and 63.7 mg kg^?1 when administered orally in mice. Both compounds were found to increase serum creatine kinase levels in mice, indicating that T. terreum may be the cause of mushroom poisoning ultimately leading to rhabdomyolysis.     

Copper‐Catalyzed One‐Pot Denitrogenative–Dehydrogenative–Decarboxylative Coupling of β‐Ketoacids with Trifluorodiazoethane: Facile Access to Trifluoromethylated Aldol Products

A novel copper‐catalyzed one‐pot cross‐coupling of β‐ketoacids with in situ generated trifluorodiazoethane has been developed. This reaction provides a direct and efficient method, in which one C?C bond and one C?O bond were formed in a carbenoid center with concomitant denitrogenation–dehydrogenation–decarboxylation, to afford trifluoromethylated aldol products. In several preliminary experiments, good to high enantioselectivities were also obtained.     

Highly Enantioselective Catalytic System for Asymmetric Copolymerization of Carbon Dioxide and Cyclohexene Oxide

A new ligand can be easily prepared, and its intramolecular dinuclear zinc complexes act as a high performance catalyst for the asymmetric alternating copolymerization of cyclohexene oxide and CO₂ under very mild conditions (1 atm CO₂, room temperature), affording completely alternating polycarbonates with up to 93.8 % enantiomeric excess (ee) and 98 % yield. A high M_n value of 28 600 and a relatively narrow polydispersity (M_w/M_n ratio) of 1.43 were also achieved.     

Peripherally and Axially Carboxylic Acid Substituted Subphthalocyanines for Dye‐Sensitized Solar Cells

A series of subphthalocyanines (SubPcs) bearing a carboxylic acid group either at the peripheral or axial position have been designed and synthesized to investigate the influence of the COOH group positions on the dye‐sensitized solar cell (DSSC) performance. The DSSC devices based on SubPcs with axially substituted carboxylic acid groups showed low photovoltaic performance, whereas peripherally substituted one exhibited higher power conversion efficiency owing to improved injection from LUMO of SubPcs to the TiO₂ conduction band.     

Assembly of Na3V2(PO4)3 Nanoparticles Confined in a One‐Dimensional Carbon Sheath for Enhanced Sodium‐Ion Cathode Properties

Structural and morphological control is an effective approach for improvement of electrochemical properties in rechargeable batteries. One‐dimensionally assembled structure composed of NASICON‐type Na₃V₂(PO₄)₃ nanoparticles were fabricated through an electrospinning method to meet the requirements for the development of efficient electrode materials in Na‐ion batteries. High‐temperature treatment of electrospun precursor fibers under an argon flow provides a nonwoven fabric of nanowires comprising crystallographically oriented nanoparticles of NASICON‐type Na₃V₂(PO₄)₃ within a carbon sheath. The mesostructure comprising NASICON‐type Na₃V₂(PO₄)₃ and carbon give a short sodium‐ion transport pass and an efficient electron conduction pass. Electrochemical properties of NASICON‐type Na₃V₂(PO₄)₃ are improved on the basis of one‐dimensional nanostructures designed in the present study.     

Metal‐Free Oxidative Radical Addition of Carbonyl Compounds to α,α‐Diaryl Allylic Alcohols: Synthesis of Highly Functionalized Ketones

A metal‐free direct alkylation of simple carbonyl compounds (ketones, esters, and amides) with α,α‐diaryl allylic alcohols is described. The protocol provides facile access to highly functionalized dicarbonyl ketones by a radical addition/1,2‐aryl migration cascade. The regioselectivity of the reaction was precisely controlled by the nature of the carbonyl compound.     

Dispersion Interaction Stabilizes Sterically Hindered Double Fullerenes

By state‐of‐the‐art quantum chemical methods, we show that for bulky functional groups like cyclohexane, [20]fullerene, dodecahedrane, and C₆₀, the attractive dispersion interaction can have a greater impact on stereochemistry than the repulsive steric effect, making the compact isomer the more stable one. In particular, for the double C₆₀ adduct of pentacene 1 , the syn isomer should be the main product instead of the anti one inferred in the original synthesis experiment (Y. Murata et al., J. Org. Chem.­ 1999 , 64, 3483). With and without dispersion interactions taken into account, the Gibbs energy difference ΔG(syn?anti) is ?6.36 and +1.15 kcal mol^?1, respectively. This study reminds us that dispersion interactions as well as electrostatic or hyperconjugation effects, etc. can lead to some unusual stereochemical phenomena.     

A Facile Asymmetric Approach to the Multicyclic Core Structure of Mangicol A

Chiral propargylic ether‐based triene–ynes are synthesized with high enantiomeric purity by employing an asymmetric enyne addition to aldehydes catalyzed by 1,1′‐bi‐2‐naphthol in combination with ZnEt₂, Ti(OiPr)₄ and dicyclohexylamine at room temperature. These substrates are found to undergo a one‐pot domino Pauson–Khand and Diels–Alder cycloaddition catalyzed by [RhCl(CO)₂]₂ under CO to generate a series of multicyclic products with high chemoselectivity and stereoselectivity. These products contain the multicyclic core structure of mangicol A which could facilitate the synthesis and study of this class of natural products.     

Visible‐Light‐Induced CS Bond Activation: Facile Access to 1,4‐Diketones from β‐Ketosulfones

A novel method for the synthesis of 1,4‐diketones from β‐ketosulfones was developed by means of a visible light‐induced C?S bond activation process. Symmetrical and unsymmetrical 1,4‐diketones can be easily prepared in moderate to good yields.