Recent development of ortho-C–H functionalization of aryl sulfoxides through [3,3] sigmatropic rearrangement

Sulfoxide-promoted ortho-C–H functionalization reactions of aromatic compounds have emerged as powerful tools for organic synthesis. Among them, [3,3] sigmatropic rearrangement induced by interrupted Pummerer reaction or electrophilic activation of sulfoxides has proved to be a fruitful strategy due to its versatility and high reaction efficiency. This digest paper mainly focuses on recent progress on C–H functionalization reactions of aryl sulfoxides via [3,3] sigmatropic rearrangement of sulfonium-tethered intermediates.     

Structural phase stability of Se clusters in zeolites

The effect of confinement on the structural phase of Se clusters in zeolites (LTA and FAU) has been studied in the temperature range of 300 ～ 550K by Raman scattering and differential scanning calorimetry. It has been found in Raman spectra that the structural unit and phase stability of Se clusters are greatly affected by the geometrical restriction in the zeolites. No clear phase transformation was observed by DSC measurements for Se clusters in LTA zeolites, while Se clusters in FAU zeolites exhibit a distinct endothermic peak which is ascribed to a glass transition. The glass transition temperature of amorphous Se (320 K) is remarkably elevated when Se rings/chains are incorporated in FAU zeolites; the higher glass transition temperature for the smaller window diameter of zeolites. We have also found that the activation energy for the glass transition is decreased drastically in the zeolites; the smaller activation energy for the smaller window size. The observations imply that the kinetics of the structural relaxation at the glass transition of Se is significantly influenced by the absence of inter-cluster interaction and that the thermokinetic dimension becomes lower owing to the geometrical restriction in the zeolites.     

Nickel-catalyzed carboxylation of aryl and vinyl chlorides employing carbon dioxide

Nickel-catalyzed carboxylation of aryl and vinyl chlorides employing carbon dioxide has been developed. The reactions proceeded under a CO(2) pressure of 1 atm at room temperature in the presence of nickel catalysts and Mn powder as a reducing agent. Various aryl chlorides could be converted to the corresponding carboxylic acid in good to high yields. Furthermore, vinyl chlorides were successfully carboxylated with CO(2). Mechanistic study suggests that Ni(I) species is involved in the catalytic cycle.