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Copper or silver salts promote a domino addition-cyclization reaction between terminal alkynes, carbon disulfide, and oxiranes in a regioselective manner to afford 1,4-oxathiane derivatives in good yield.

A cubic phase of pure MgO nanopowders was prepared in an aqueous solution containing freshly squeezed orange juice with pulp and characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FE‐SEM), energy‐dispersive X‐ray spectroscopy (EDS), and Fourier transform infrared (FT‐IR) spectroscopic techniques. The catalytic potential of MgO nanopowders was evaluated in preparation of pyrano[4,3‐d]thiazolo[3,2‐a]pyrimidine and chromeno[4,3‐d]thiazolo[3,2‐a]pyrimidines derivatives using the three simple methods including thermal, ultrasonic irradiation, and high‐speed ball milling (HSBM) technique under solvent‐free conditions. All products were successfully formed in high yields.

Unsymmetrical piperazines are key constituents of many pharmaceuticals. Given that the selective introduction of an aryl and alkyl motif onto the piperazine is not always straightforward, direct arylation and alkenylation of 1,4‐diaza‐bicyclo[2.2.2]octane would obviate the inefficiencies associated with the preparation of these target molecules. We have utilized alkyl halides, aryl or alkenyl triflates, and 1,4‐diaza‐bicyclo[2.2.2]octane for the synthesis of N‐alkyl‐N′‐aryl or alkenylpiperazines. The optimum conditions are developed using CuCl, t‐BuOLi in NMP. Alkenyl triflates requires N,N′‐dimethylethylenediamine and higher temperature to afford the desired cross‐coupled product. Substrates bearing electron‐deficient and electron‐rich groups were successfully coupled under the optimum reaction conditions.

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A carbon–carbon bond formation reaction between isocyanides and benzene derivatives is reported. In contrast to traditional cross-coupling reactions, which require aryl halides or pseudohalides, we use a palladium catalyst to generate the aryl–palladium through C–H bond activation of arenes. This method offers an attractive approach to a range of benzamides from readily accessible benzene derivatives.