Iodine as a versatile catalyst for the hydroalkylation of vinyl arenes with 1,3-diketones

The vinyl arenes undergo smooth hydroalkylation with 1,3-diketones in the presence of 10 mol % of iodine to afford phenethyl diketones and ketoesters in good yields in short reaction times. The use of inexpensive and readily available molecular iodine makes this method quite simple, more convenient and practical.     

Solvent-free hydroalkylation of olefins with 1,3-diketones catalyzed by phosphotungstic acid

An efficient and convenient method for the direct hydroalkylation of styrene and norborene with 1,3-diketones has been developed by using 12-phosphotungstic acid as an eco-friendly, and air- and moisture-tolerable catalyst. Reactions proceeded without any solvent, providing a clean access to alkylated 1,3-diketones.     

Boric acid as an efficient catalyst for the synthesis of 1,1-diacetate under solvent-free condition

Boric acid (BO₃H₃) is an inexpensive, efficient and mild catalyst for the synthesis of 1,1-diacetate (acylal) from the various aromatic and heteroaryl aldehydes with acetic anhydride at room temperature under solvent-free condition. The present method does not involve any hazardous organic solvents or catalysts. This method gives notable advantages such as excellent chemoselectivity, mild reaction condition, short reaction times and excellent yield.     

Selenonium ionic liquid as an efficient catalyst for the synthesis of thioacetals under solvent-free conditions

Acidic ionic liquid butyl ethyl phenyl selenonium tetrafluoroborate, [BEPSe]BF₄, was successfully employed as a catalyst for the synthesis of several dithioacetals in the absence of a solvent. The method is general and selectively afforded thioacetals derived from aldehydes and ketones in good yields.     

Magnesium perchlorate as an efficient catalyst for the synthesis of imines and phenylhydrazones

Magnesium perchlorate has been found to be an efficient catalyst for the synthesis of imines and phenylhydrazones by the reaction of carbonyl compounds with amines and phenylhydrazine in high yields at room temperatures and in short times. The condensation of less electrophilic carbonyl compounds with poorly nucleophilic amines affords the imines in excellent yields.     

Proline-catalyzed aldol reactions of acyl cyanides with acetone: an efficient and convenient synthesis of 1,3-diketones

The aldol-type addition of acetone towards (un)substituted benzoyl, heteroarylcarbonyl or α,β-unsaturated acyl cyanides was efficiently catalyzed by l-proline (30 mol %) to give 2-hydroxy-4-oxo-2-substituted pentanenitriles. Upon the treatment with sodium hydroxide, the adducts transformed to 1,3-diketones in good-to-excellent yield, furnishing an efficient and convenient method for the regioselective synthesis of 1,3-diketones.     

Wet 2,4,6-trichloro-1,3,5-triazine(TCT)as an efficient catalyst for the synthesis of 2,4,6-triarylpyridines under solvent-free conditions

<正>An efficient one-pot synthesis of 2,4,6-triarylpyridines has been described.This involves the three-component reaction of aldehydes,ketones and ammonium acetate in the presence of a catalytic amount of wet 2,4,6-trichloro-1,3,5-triazine(TCT) under solvent-free condition at 130℃.     

N-Methylimidazole-promoted efficient synthesis of 1,3-oxazine-4-thiones under solvent-free conditions

Abstract  A novel method for oxazine ring formation is established using the reaction of ammonium thiocyanate and acid chlorides with napthols in the presence of N-methylimidazole to afford [1,3]oxazine-4-thione derivatives in excellent yields. Graphical abstract        

Rapid and efficient synthesis of new chiral aromatic amide molecular tweezers under solvent-free conditions using microwave

An efficient and simple method for the synthesis of new chiral aromatic amide molecular tweezers by irradiation with microwave under solvent-free conditions has been developed.Its main advantages are short reaction times.good conversions and the environmentally friendly nature of the process.     

Tungstate sulfuric acid as an efficient catalyst for the synthesis of benzoxazoles and benzothiazoles under solvent-free conditions

Tungstate sulfuric acid (TSA) has been found to be an efficient and reusable catalyst for the synthesis of benzoxazole and benzothiazole derivatives via reactions of orthoesters with o-aminophenols or o-aminothiophenols in high yields.     

Using Pd-salen complex as an efficient catalyst for the copper-and solvent-free coupling of acyl chlorides with terminal alkynes under aerobic conditions

<正>The palladium-salen complex palladium(Ⅱ) N,N'-bis{[5-(triphenylphosphonium)-methyl]salicylidene}-1,2-ethanediamine chloride was found to be a highly active catalyst for the copper- and solvent-free coupling reaction of terminal alkynes with different acyl chlorides in the presence of triethylamine as base,giving excellent ynones under aerobic conditions.     

Iodine as an extremely powerful catalyst for the acetylation of alcohols under solvent-free conditions

Iodine was found to promote quantitative acetylation of alcohols in a very short time with an equimolar amount of acetic anhydride under solvent-free conditions at room temperature.     

Highly efficient aza-Michael reactions of aromatic amines and N-heterocycles catalyzed by a basic ionic liquid under solvent-free conditions

A task-specific basic ionic liquid, [Bmim]OH, has been introduced as a catalyst for the aza-Michael addition of aromatic amines and N-heterocycles to cyclic or acyclic ketones under neat conditions. The catalyst can be recycled for subsequent reactions without any appreciable loss of efficiency.     

Zirconyl triflate as an efficient and reusable catalyst for one-pot synthesis of 1-amidoalkyl-2-naphthols under solvent-free conditions

In the present work, the preparation of 1-amidoalkyl-2-naphthols via one-pot three-component condensation of amides, aldehydes, and β-naphthol in the presence of catalytic amounts of zirconyl triflate, as a highly efficient, low toxic, stable and non-hygroscopic catalyst under solvent-free conditions is reported. This low-cost procedure offers several other advantages such as short reaction times and good to excellent yields.     

Copper(II) tetrafluoroborate as an extremely efficient catalyst for 1,3-dithiolane/dithiane formation from carbonyl compounds under solvent-free conditions at room temperature

Copper(II) tetrafluoroborate hydrate is a new and extremely efficient catalyst for 1,3-dithiolane/dithiane formation from aromatic, heteroaromatic and aliphatic aldehydes and cyclic saturated ketones in 1-5 min under solvent-free conditions at room temperature. The reaction is compatible with other functionalities such as ether, ester, hydroxyl, halide, nitro and cyano groups and exhibits excellent chemoselectivity. α,β-Unsaturated aldehydes/ketones lead to selective formation of 1,3-dithiolanes instead of Michael addition products. For substrates bearing an aldehyde and a ketone carbonyl group, chemoselective dithiolane formation takes place with the aldehyde.     

An efficient catalyst for ring opening of epoxides with phenol and thiophenol under solvent-free conditions

An efficient and rapid procedure for ring opening reaction of various epoxides with phenol and thiophenol derivatives was developed. The procedure can be obtained at room temperature under solvent-free condition in presence of (C₄H₁₂N₂)₂[BiCl₆]Cl·H₂O (1 mol %). This catalyst can be reused several times without significant loss of activity.     

A simple and efficient one-pot synthesis of 1,4-dihydropyridines using heterogeneous catalyst under solvent-free conditions

One-pot condensation of β-dicarbonyl compounds with aldehydes and ammonium acetate in the presence of HClO₄–SiO₂ at 80 °C under solvent-free conditions with good to excellent yields. The catalyst is easily prepared, stable, reusable and efficiently used under reaction conditions.     

Silica-supported antimony(III) chloride as an efficient heterogeneous catalyst for the synthesis of aminopropenones and 3-aminopropenoates under solvent-free conditions

A convenient and efficient procedure has been developed for the synthesis of 3-aminoprop-2-en-1-ones and 3-aminoprop-2-enoates catalyzed by silica-supported antimony(III) chloride at room temperature under solvent-free conditions. The reaction takes a short time and ensures good to excellent yields of the products. Both aromatic and aliphatic amines and various 1,3-dicarbonyl compounds, including β-ketoesters and β-diketones, can be involved. Published in Russian in Zhurnal Organicheskoi Khimii, 2009, Vol. 45, No. 1, pp. 25–28. The text was submitted by the authors in English.