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This study describes an efficient approach to access oxime ethers via P(III)-mediated O–H bond insertion reaction of oximes with α-keto esters. The strategy involves the protonation of in situ generated Kukhtin–Ramirez adducts, followed by SN2-type reaction. Important features include a good functional group tolerance, operational simplicity, and application to gram scale synthesis and the synthesis of an acaricide. [ABSTRACT FROM AUTHOR]

To investigate the effects of girdling on the water relation of trees, we measured a number of water-status parameters and morphological features following trunk and branch girdling of Chamaecyparis pisifera Siebold & Zucc. Girdling caused a marked reduction in the water-conduction area of the trunk cross section at the girdled part. Some girdled trees generated intense acoustic emissions (AE), simultaneously decreased leaf water potentials (LWP), and then died within 1 year. However, others lived for more than 2 years after girdling. In these survivors, the water-conduction area of the trunk cross section was reduced but not entirely blocked, and LWP decreases did not occur. Consequently, we conclude that girdling affects xylem water conductivity and sometimes causes short-term (within 1 year) tree death by blocking water uptake from soil to leaves. The results of this study on whether tree death from girdling occurs sooner or later could be important in the use of girdling for thinning management. Key words: girdling, tree death, water status, water conductivity, cavitation. Pour etudier les effets de l'annelation sur les relations hydriques chez les arbres, nous avons mesure quelques parametres du bilan hydrique et des caracteristiques morphologiques apres l'annelation de branches et du tronc de Chamaecyparis pisifera Siebold & Zucc. L'annelation a reduit de facon marquee la portion de la section radiale du tronc conductrice d'eau dans la partie annelee. Certains arbres anneles ont generes d'intenses emissions acoustiques, ont vu diminuer simultanement le potentiel hydrique foliaire et sont ensuite morts en dedans d'un an. D'autres cependant ont vecu pendant plus de deux ans apres avoir ete anneles. Chez ces survivants, la portion de la section radiale du tronc conductrice d'eau a ete reduite mais pas entierement bloquee et le potentiel hydrique foliaire n'a pas diminue. Consequemment, nous concluons que l'annelation affecte la conductivite hydraulique du xyleme et cause quelques fois la mort des arbres rapidement en bloquant le transport de l'eau du sol vers les feuilles. Les resultats de cette etude pour savoir si la mort des arbres causee par l'annelation survient rapidement ou non pourraient etre importants si on voulait utiliser l'annelation pour pratiquer une eclaircie. [Traduit par la Redaction] Mots-cles: annelation, mort des arbres, bilan hydrique, conductivite hydraulique, cavitation., Introduction It is well known that successful girdling kills trees (Fujimori 2001). As labor costs increase and forest managers seek other methods to alter stand density, especially in dense or [...]

3‐(2H)‐isoxazolone is an important skeletal structure in medicinal and agricultural chemistry. However, its synthetic methodology has limited substrate scope and requires unconventional substrate synthesis. Meanwhile, gold‐catalyzed intramolecular oxidative cross‐coupling involving the 5/6‐endo‐dig cyclization of substrates bearing an ynone structure has not been reported because of an undesirable protonation as a side‐reaction. Thus, we hypothesized that the reactivity of cyclic N‐alkoxypropiolamides would suppress protonation and allow dual functionalization. As a result, sequential gold‐catalyzed 5‐endo‐dig cyclization, oxidative cross‐coupling, and hydroxylation of N‐alkoxypropiolamides was developed to synthesize 4‐aryl‐3‐(2H)‐isoxazolones with a hydroxy group. In an optimization study, dimethylformamide (DMF) and H2O were effective solvents for the sequential reaction. This method enabled 3‐(2H)‐isoxazolone backbone synthesis with the introduction of an aryl and hydroxy group in a single procedure. Moreover, a tolerance toward reactive functional groups, such as ketocarbonyl groups, was observed. Some chemical transformations of the synthesized 4‐aryl‐3‐(2H)‐isoxazolone were conducted to demonstrate the feasibility of functional group interconversion, C−C bond formation, and additional heterocycle synthesis. Notably, a fluorescent tetracyclic heterocycle was obtained by intramolecular oxidative cross‐coupling. Control experiments indicated that the reactivity for protonation was suppressed by an alkoxyamide moiety. Therefore, the chemoselectivity of oxyarylation was improved. Finally, density functional theory (DFT) calculations were performed to estimate the reaction pathway, which suggested that ring‐opening involving solvents (H2O or DMF) is important for these sequential reactions. [ABSTRACT FROM AUTHOR]

The intermolecular radical addition to chiral nitrones was examined in a study. The isopropyl radical addition to Oppolzer's camphorsultam derivative of glyoxylic nitrone proceeded with excellent to give the desired isopropylated product accompanied by the diisopropylated product.

The article titled "Front Cover: Benzocoumarin-Fused Triskelions Exhibit AIEE Due to Inhibited Molecular Inversion" explores the crystal packing and properties of three benzocoumarin-fused triskelion-shaped dyes. These dyes have unique helices, twists, thicknesses, and planarities due to the different positions of the benzo group on the coumarin platform. The modifications also impact the molecular assemblies, molecular inversion processes, and emission properties of the dyes. The research article provides more detailed information on these findings. [Extracted from the article]