Development of new green strategies based on Brønsted and Lewis acid catalysis in organic synthesis

Environmental protection is one of the greatest themes of the XXI century. For what concerns chemistry, in the early 1990’s, even before its current formal and exhaustive definition, given by Paul T. Anastas and John C. Warner in 1998, the term "green chemistry" starts to appear in the literature. Anastas and Warner formulated a list of 12 principles, that constitute the most complete definition of green chemistry. Herein, an effort towards the fulfillment of these principles is presented with respect to: 1) the development of a catalytic system based on hydrate ferric sulfate for the hydration of internal alkynes; 2) an approach to the synthesis of a new family of chiral phosphates for organocatalysis

Turning renewable feedstocks into a valuable and efficient chiral phosphate salt catalyst

Solketal, the chiral acetonide of glycerol, has been employed as the starting material in the design of a novel punctually chiral phosphate sodium salt for catalytic applications in organic and asymmetric synthesis. The racemate and the two enantiomers of the substrate are economic and commercially available, straightforwardly prepared in high yields from naturally occurring feedstocks. Therefore, remarkably, both enantiomers of the final catalyst can be synthesized by simple procedures in high yield and in compliance with several principles of green chemistry. To further demonstrate the usefulness of the novel catalyst, its application in a solventless protocol for cyanohydrin synthesis from a series of aldehydes has been presented

Critical assessment of the sustainability of deep eutectic solvents: a case study on six choline chloride-based mixtures

An outline of the advantages, in terms of sustainability, of Deep Eutectic Solvents (DESs) is provided, by analyzing some of the most popular DESs, obtained by the combination of choline chloride, as a hydrogen bond acceptor, and six hydrogen bond donors. The analysis is articulated into four main issues related to sustainability, which are recurrently mentioned in the literature, but are often taken for granted without any further critical elaboration, as the prominent green features of DESs: their low toxicity, good biodegradability, renewable sourcing, and low cost. This contribution is intended to provide a more tangible, evidence-based evaluation of the actual green credentials of the considered DESs, to reinforce or question their supposed sustainability, also in mutual comparison with one another

Usefulness of the Global <i>E</i> Factor as a Tool to Compare Different Catalytic Strategies: Four Case Studies

The global E factor (EG factor) has recently been introduced, in the context of asymmetric organocatalysis, as a new green chemistry metric to take into consideration the synthesis of the catalyst in the overall economy of the synthetic process of a given chiral molecule in optically pure form. Herein, its further usefulness in comparing diverse catalytic systems, even different from organocatalysts, is shown by the analysis of four case studies