title: Efficient synthetic protocols in glycerol under heterogeneous catalysis.
abstract: The massive increase in glycerol production from the transesterification of vegetable oils has stimulated a large effort to find novel uses for this compound. Hence, the use of glycerol as a solvent for organic synthesis has drawn particular interest. Drawbacks of this green and renewable solvent are a low solubility of highly hydrophobic molecules and a high viscosity, which often requires the use of a fluidifying co-solvent. These limitations can be easily overcome by performing reactions under high-intensity ultrasound and microwaves in a stand-alone or combined manner. These non-conventional techniques facilitate and widen the use of glycerol as a solvent in organic synthesis. Glycerol allows excellent acoustic cavitation even at high temperatures (70-100 °C), which is otherwise negligible in water. Herein, we describe three different types of applications: 1) the catalytic transfer hydrogenation of benzaldehyde to benzyl alcohol in which glycerol plays the dual role of the solvent and hydrogen donor; 2) the palladium-catalyzed Suzuki cross-coupling; and (3) the Barbier reaction. In all cases glycerol proved to be a greener, less expensive, and safer alternative to the classic volatile organic solvents.
authors.affiliation: Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, Via P. Giuria 9, 10125 Torino, Italy. giancarlo.cravotto@unito.it
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Cravotto
authors.forename: Laura
authors.initials: L
authors.lastname: Orio
authors.forename: Emanuela Calcio
authors.initials: EC
authors.lastname: Gaudino
authors.forename: Katia
authors.initials: K
authors.lastname: Martina
authors.forename: Dorith
authors.initials: D
authors.lastname: Tavor
authors.forename: Adi
authors.initials: A
authors.lastname: Wolfson
mesh_terms: D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D005990:Glycerol / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry
chemical_list: D012997:Solvents; D005990:Glycerol