The oxidative coupling of carboxylic acids with liquid ketones and cyclic ethers has been accomplished in minutes using t-butyl hydroperoxide in the presence of tetrabutylammonium iodide under microwave irradiation in the absence of a solvent. In addition to drastically shortening the reaction times, the use of microwaves resulted, in general, in yields equal to or higher than those obtained by conventional heating.

Treatment of alkynes with diethyl phosphite and t-butyl hydroperoxide in the presence of [Cu­(MeCN)4]­BF4 under microwave irradiation produced the oxyphosphorylation of the triple bond, giving rise to the corresponding β-ketophosphonates in moderate-to-good yields. When the triple bond was conjugated to a carbonyl group bearing an aromatic ring, it led to the cyclization of the resulting ketone intermediate, producing eventually different phosphonylated indenones.

A copper-iron-based catalyst has been prepared by a low-temperature co-precipitation and sonication method. The use of high-energy ultrasound reduces the time required for the preparation process from one workweek to...