Glycerol

Abstract

Dihydroxyacetone was selectively obtained from cationic palladium catalyzed glycerol oxidation using benzoquinone or oxygen as the terminal oxidant. This protocol is especially suitable for substrates containing vicinal diol groups. The mechanism involves reversible palladium alkoxide formation with the oxidation of palladium as the turnover-limiting step. 10A regio- and chemoselective reduction of nitroarenes and carbonyl compounds over recyclable magnetic ferrite nickel nanoparticles (Fe3O4-Ni) was achieved by using glycerol as the hydrogen source. The catalyst was reused eight times without any significant loss in catalytic activity and selectivity. 11Shi and co-workers used glycerol as the hydrogen source in a Au/Ag-Mo-nanorods catalyzed tandem reaction of alcohols and nitrobenzenes, which generated N-alkyl amines and imines. The reaction involved reduction of nitrobenzene, aminealdehyde coupling, and imine reduction. 12Aryloxypropanediols with pharmacological properties (for example guaifenesin) are widely found in nature and are also important intermediates for the synthesis of other drugs such as methocarbamol or chlorphenesin carbamate. Glycerol was selectively converted into aryloxypropanediols under solvent-free conditions in a one-pot reaction through in situ formed glycerol carbonate. 13 Glycerol was converted into acrylonitrile in a solvent-free microwave- activated process using an alumina-supported V-Sb-O catalyst. The mild reaction conditions reported required only a short reaction time, making it a highly efficient new process for the valorization of glycerol.14Wever and co-workers reported a one-pot four-enzyme cascade reaction for the synthesis of enantio- and diastereomerically pure carbohydrate analogues from glycerol and a variety of aldehydes without protectiondeprotection steps. This protocol was successfully applied to the total synthesis of the naturally occurring azasugar D-fagomine. 15. © Georg Thieme Verlag Stuttgart New York.