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We have developed a simple and direct method for the synthesis of diaryl ether under mild reaction conditions using an oxygen bridged bimetallic CuMoO4 nanocatalyst. The catalyst tolerated a wide range of substrates with various functional groups. The catalyst is efficient and recyclable. This methodology allowed easy access to nitrofen derivatives (herbicides) from unactivated 2,4-dichlorophenol, which are important for agriculture and pharmaceuticals. [ABSTRACT FROM AUTHOR]

Most non-palladium catalysts employed in Sonogashira cross-coupling work at high temperatures of 120–140 °C and with well-defined ligands. Palladium-based catalysts with bulky and electron-rich phosphine ligands generally show the best performance for the above-mentioned cross-coupling procedure. Herein, we report a new protocol for Csp–Csp2 Sonogashira cross-coupling between a terminal alkyne and aryl halide using the cheap and commercially available catalyst CuSeO3·2H2O. The title reaction proceeds using a variety of terminal alkynes, affording diaryl or aryl–alkyl acetylenes in high yields under mild conditions in the absence of ligands. Alkyl acetylenes, ethynylsilanes, and alkynols are efficiently coupled with aryl iodides and aryl bromides. The mechanism of the reaction was evaluated using computational DFT studies. To the best of our knowledge, this is the first example of the use of an oxygen-bridged copper-based bimetallic catalyst for Csp–Csp2 Sonogashira cross-coupling reactions under mild conditions. The reaction is palladium-free up to a limit of 0.2 ppm. [ABSTRACT FROM AUTHOR]

This study summarizes the stereochemical outcomes of [3+2] cycloaddition of allene molecules with 1,3-dipolar carbonyl ylides derived from rhodium carbene-mediated diazo decomposition for the formation of highly diastereoselective poly oxacarbocycles. Since only rhodium is employed for this purpose, further exploration of the reaction with other transition metals is lacking. A little research in this area surely depicts the need for further exploration of this technique using other transition metals and ylides (sulfur and nitrogen) for the synthesis of oxa-, aza-, and thia-bridged heterocarbocycles. These polyheterocycles will be future drug candidates being structurally analogous to anthecularin, artemisinin, englerin and intracarene. This review presents a future outlook for organic chemists for further exploration of the synthesis of bridged polyheterocarbocycles. [ABSTRACT FROM AUTHOR]

Herein, we report a new protocol for the dehydrogenative oxidation of aryl methanols using the cheap and commercially available catalyst CuSeO3·2H2O. Oxygen-bridged [Cu–O–Se] bimetallic catalysts are not only less expensive than other catalysts used for the dehydrogenative oxidation of aryl alcohols, but they are also effective under mild conditions and at low concentrations. The title reaction proceeds with a variety of aromatic and heteroaromatic methanol examples, obtaining the corresponding carbonyls in high yields. This is the first example using an oxygen-bridged copper-based bimetallic catalyst [Cu–O–Se] for dehydrogenative benzylic oxidation. Computational DFT studies reveal simultaneous H-transfer and Cu–O bond breaking, with a transition-state barrier height of 29.3 kcal mol−1. [ABSTRACT FROM AUTHOR]

We disclosed new bimetallic BaMoO4 nanoparticles for the C–S cross-coupling reaction. The C–S cross-coupling reaction of alkyl/aryl thiols with haloarenes was accomplished with high yields. The reaction has good functional group tolerance and selectivity. This is an efficient protocol for synthesizing the building blocks of pharmaceuticals containing C–S bonds. The catalyst is recyclable. The unactivated bromo- and 4-acetyl fluoro-arenes can well couple to afford thioethers in high yields. The reaction is believed to proceed by oxidative addition and reductive elimination. [ABSTRACT FROM AUTHOR]

Herein we disclosed inexpensive copper(II) bimetallic CuMoO4 nanoparticles for the C–N cross-coupling reaction of alkyl and aryl amines with haloarenes. The reaction proceeds under mild and ligand free conditions. The catalyst is recyclable and effective for a wide range of amines and haloarenes. Here, the efficiency of the Cu(II) catalyst is increased by doping molybdenum metal. The bimetallic nanoparticles are anticipated to proceed via normal oxidative addition and reductive eliminations. [ABSTRACT FROM AUTHOR]

Using a prototypical Diels–Alder reaction as benchmark, we show that dicationic halogen-bond donors are capable of activating a neutral organic substrate. By various comparison experiments, the action of traces of acid or of other structural features of the halogen-bond donor not related to halogen bonding are excluded with high certainty. [ABSTRACT FROM AUTHOR]

Bi- and tridentate polycationic halogen bond donors based on 5-iodo-1,2,3-triazolium groups have been synthesized by 1,3-dipolar cycloaddition reactions. These halogen-based Lewis acids have been evaluated as activators in a halide-abstraction benchmark reaction.