Dehydrogenative cycloisomerization/arylation sequence of heteroatom nucleophile‐tethered unactivated alkynes provides a facile and powerful approach to C−C bond formation between the generated heterocycles and unfunctionalized arenes. Here, we describe a hypervalent iodine(III)‐catalyzed synthesis of oxazoles concomitant with the introduction of aryl groups into side chain from N‐propargyl carboxamides and arenes, representing first C(sp3)−C(sp2) bond formation by the catalytic dehydrogenative cycloisomerization/arylation reaction in exo‐dig modes.
Controlling the formation of nanosized branched nanoparticles with high uniformity is one of the major synthetic challenges to achieve nanocatalysts with improved activity and stability. Using a cubic-core hexagonal-branch mechanism to form highly monodisperse branched nanoparticles we vary the length of the nickel branches. Lengthening the nickel branches, with their high coverage of active facets, is shown to improve activity for electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) as an example for biomass conversion.The synthesis of well-defined 3D nanostructures has been achieved for the fabrication of noble metal nanoparticles. [1][2][3][4][5] As the focus of energy conversion shifts towards earth abundant transition metal catalysts and alkaline electrolytes, approaches are needed to synthesize highly defined and uniform nanoparticles made of first row transition metals. A critical feature for uniform nanoparticles is branch dimension and the surface faceting. [5,6] Ideally for catalysis, nanoparticles should have branch diameters of less than 25 nm to achieve highest possible surface area. [7,8] The synthesis also needs to control branch length to enable high exposure of specific active facets. [9][10][11] This is vital because well-defined faceting determines the active sites available for catalysis, as has shown to be crucial for branched nanoparticle catalysts. [1,2,12]
The front cover picture illustrates iodoarene as a precatalyst and dimethyl(fluoro)‐λ6‐sulfane as a real oxidant derived from DMSO and F‐TEDA‐PF6, and the Japanese kanji stands for the initial letters of key elements, sulfur, iodine, and fluorine. A hypervalent iodine(III) catalyst, generated in situ from these reagents, is effective on the dehydrogenative cycloisomerization/arylation reaction of N‐propargyl carboxamides and arenes. Details can be found in the Update by Saito and collaborators (Y. Umakoshi, Y. Takemoto, A. Tsubouchi, V. V. Zhdankin, A. Yoshimura, A. Saito, Adv. Synth. Catal. 2022, 364, 2053–2059; DOI: 10.1002/adsc.202200219)
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