A novel application of nanoparticles of paramagnetic magnetite (Fe 3 O 4 ) as an efficient catalyst for carbon-carbon bond formation via the Sonogashira-Hagihara reaction under heterogeneous ligand-free conditions in ethylene glycol (EG) is des-A C H T U N G T R E N N U N G cribed. By using this catalyst, arylalkynes are produced from the reaction of aryl iodides and activated heteroaryl bromides with alkynes. The results are reproducible using the catalyst, which was prepared from different sources. The catalyst is easily separated by an external magnetic field from the reaction mixture. The separated catalyst can be recycled for several consecutive runs without appreciable loss of its catalytic activity.

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An active and stable magnetically separable Pd nanocatalyst was prepared and characterized. The nanocatalyst exhibited excellent activities and reusabilities in aqueous phase processes including the O-arylation of phenols and Sonogashira cross-coupling reactions. The proposed protocol features mild reaction conditions and an extraordinary simplicity and efficiency using NaOH as base in water. † Electronic supplementary information (ESI) available. See

In this article, we have developed a new protocol for the thioarylation of structurally diverse alkyl bromides such as benzyl, cinnamyl, n-octyl, cyclohexyl, cyclopentyl, and tert-butyl bromides with aryl iodides, bromides and an activated chloride using thiourea catalyzed by copper(I) iodide in wet polyethylene glycol (PEG 200) as an eco-friendly medium in the presence of potassium carbonate at 80 and 100 8C under an inert atmosphere. The process is free from foul-smelling thiols which makes this method more practical for the thioetherification of aryl halides. Another important feature of this method is the variety of alkyl bromides which are commercially available for the in situ generation of thiolate ions with respect to the existing protocols in which the less commercially available thiols are directly used for the preparation of arylthio ethers.

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The 2,2'-, 3,3'-, and 4,4'-azopyridines (azpy) and their alkyl pyridinium ionic liquids were studied as a new class of electron-deficient reagents for Mitsunobu esterification reactions. Among these compounds, 4,4'-azopyridine was found to be the most suitable one for esterification and thioesterification reactions. This new reagent promises to provide general and complementary solutions for separation problems in Mitsunobu reactions without restricting the reaction scope and facilitates the isolation of its hydrazine byproduct. The pyridine hydrazine byproduct can be simply recycled to its azopyridine by an oxidation reaction.

Heteropoly acids are effective solid catalysts for the thioacetalization of carbonyl compounds. Tungstophosphoric acid (H 3 PW 12 O 40), was found to be an effective and a highly selective catalyst for the thioacetalization of aldehydes, ketones and for the transthioacetalization of acetals, acylals and O,S-acetals which proceeded in excellent yields in the absence of solvent. The catalyst has also been successfully applied to the chemoselective conversion of aor b-diketones and a b-keto ester into the corresponding dithioacetals. Sterically hindered carbonyl compounds such as camphor and benzophenone were also converted to their corresponding thioacetals in refluxing petroleum ether in 89-94% yields. Surprisingly, anthrone was reduced to anthracene in 91% yield.