Microwave-accelerated conjugate addition of aldehydes to α,β-unsaturated ketones

Aldehydes undergo smooth conjugate addition to α,β-unsaturated ketones in the presence of 5-(2-hydroxyethyl)-1,3-thiazolium halides and DBU adsorbed onto the surface of basic alumina under microwave irradiation and solvent-free conditions to afford 1,4-diketones in enhanced yields and reduced reaction times compared to conventional methods

Niobium(V) chloride-catalyzed C-H insertion reactions of α-diazoesters: synthesis of β-keto esters

Aldehydes react readily with ethyl diazoacetate in the presence of 5 mol% of NbCl5 in dichloromethane to produce the corresponding β-keto esters in good yields with high selectivity. This method is very useful for the preparation of β-keto esters from both electron-rich as well as electron-deficient aromatic aldehydes under mild reaction conditions

CeCl<SUB>3</SUB>&#183;7H<SUB>2</SUB>O/NaI-promoted stereoselective aldol coupling of &#945;,&#946;-acetylenic ketones

A simple and highly stereoselective method has been developed for the synthesis of (Z)-&#946;-iodo Baylis-Hillman adducts using CeCl3&#183;7H2O/NaI as an inexpensive and readily available reagent system. High conversions and enhanced Z-selectivity together with the environmentally benign nature of the CeCl3/NaI reagent system makes this method an attractive alternative to established methods

Microwave thermolysis-Part IX: A selective and rapid oxidation of benzylic alcohols using clay supported ammonium nitrate

500-502The oxidation of a variety of benzylic alcohols to carbonyl compounds using clay-supported ammonium nitrate “clayan” under microwave irradiation is described. The selectivity and non-solvent condition are the important features of the procedure

Montmorillonite KSF clay catalyzed one-pot synthesis of α-aminonitriles

Aryl imines, formed in situ from aldehydes and amines undergo smoothly nucleophilic addition with trimethylsilyl cyanide on the surface of montmorillonite KSF clay under mild reaction conditions to afford the corresponding α-aminonitriles in excellent yields. The solid acid can be recovered and recycled in subsequent reactions with a gradual decrease of activity

Zirconium(IV) chloride catalyzed cyclization of ortho-allylphenols: Synthesis of 2-methyl-2,3-dihydrobenzofurans

Intramolecular cyclization of ortho-allylphenols has been carried out using zirconium (IV) chloride in mild condition. This method avoids the use of expensive reagents and leads to highly functionalized dihydrobenzofurans

Gallium(III) halide promoted synthesis of 1,3,5-triaryl- 1,5-dihalo-1,4-pentadienes

Aryl substituted alkynes undergo smooth coupling with aldehydes in the presence of gallium(III) halides under extremely mild conditions to afford the corresponding 1,3,5-triaryl-1,5-dihalo-1,4-pentadienes in good yields with E,Z-selectivity. Similarly 1,3,5-triaryl-1,5-dichloro-1,4-pentadienes are also obtained with niobium(V) chloride

Convenient and efficient triton B-mediated synthesis of functionalized oxime ethers

Mild and efficient Triton B-catalyzed Michael addition of oximes to electron-deficient alkenes is described. This convenient methodology allows for the preparation of a variety of functionalized oxime ethers in high yield

Microwave thermolysis: Part III — A rapid and convenient coupling of 2-naphthols in solvent-free condition^†

2615-2617A rapid and environmentally benign method for the coupling of 2-napthols is described using copper (II) acetonylacetonate under microwave irradiation in dry media. The procedure is very convenient and avoids the use of excess solvent for reaction

Microwave thermolysis: Part IX- A rapid reduction of sulphoxides With NaH₂PO₂ in dry media

193-195Reduction of a variety of sulphoxides using sodium hypo­phosphite under microwave irradiation is described. The method avoids the use of solvent and applicable for the variety of substrates