The rapid growth of the biodiesel industry has led to a large surplus of its major byproduct, i.e. glycerol, for which new applications need to be found. Research efforts in this area have focused mainly on the development of processes for converting glycerol into value-added chemicals and its reforming for hydrogen production, but recently, in line with the increasing interest in the use of alternative greener solvents, an innovative way to revalorize glycerol and some of its derivatives has seen the light, i.e. their use as environmentally friendly reaction media for synthetic organic chemistry. The aim of the present Feature Article is to provide a comprehensive overview on the developments reached in this field.

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The first highly enantioselective intermolecular (4 + 2) cycloaddition between allenes and dienes is reported. The reaction provides good yields of optically active cyclohexenes featuring diverse substitution patterns and up to three stereocenters. Key to the success of the process is the use of newly designed axially chiral N-heterocyclic carbene− gold catalysts.

A ruthenium-arene-PTA (RAPTA) complex has been supported for the first time on an inorganic solid, that is, silica-coated ferrite nanoparticles. The resulting magnetic material proved to be a general, very efficient and easily reusable catalyst for three synthetically useful organic transformations; selective nitrile hydration, redox isomerization of allylic alcohols, and heteroannulation of (Z)-enynols. The use of low metal concentration, environmentally friendly water as a reaction medium, with no use at all of organic solvent during or after the reactions, and microwaves as an alternative energy source renders the synthetic processes reported herein "truly" green and sustainable.

The hydration of nitriles is an atom economical route to generate primary amides of great academic and industrial significance. From an academic perspective, considerable progress has been made toward the development of transition metal catalysts able to promote this hydration process under mild conditions. In this context, with regard to activity, selectivity, functional group compatibility and modes of reactivity, the most versatile nitrile hydration catalysts discovered to date are based on ruthenium complexes. Herein, a comprehensive account of the different homogeneous ruthenium catalysts described in the literature is presented. Heterogeneous ruthenium-based systems are also discussed.

The catalytic rearrangement and dehydration of aldoximes with phosphino-oxime-palladium complexes is described.

The dimeric bis(allyl)ruthenium(IV) complex [{RuCl(μ-Cl)(η 3 :η 3 -C 10 H 16 )} 2 ] (C 10 H 16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) (5) and several mononuclear species trans-[RuCl 2 (η 3 :η 3 -C 10 H 16 )(L)] (L = two-electron-donor ligand) (6) derived from 5 have been checked as catalysts for the addition of carboxylic acids onto terminal alkynes using water as a green reaction medium. The best results in terms of activity and regioselectivity were obtained with the mononuclear derivative trans-[RuCl 2 -(η 3 :η 3 -C 10 H 16 )(PPh 3 )] (6a), which was able to promote the selective Markovnikov addition of both aromatic and aliphatic carboxylic acids to a large variety of terminal alkynes, enynes, and diynes as well as propargylic alcohols. In this way, a wide number of enol esters and β-oxo esters could be synthesized in moderate to good yields under mild conditions (60 °C) in an aqueous medium.

A simple and highly efficient method for the selective reduction of the C=C bond in allylic alcohols has been developed using the ruthenium(II) catalyst [{RuCl(mu-Cl)(eta(6)-C(6)Me(6)}2].