Assessment of the organocatalytic activity of chiral l-Proline-based Deep Eutectic Solvents based on their structural features

Asymmetric Organocatalysis in Deep Eutectic Solvents

“…So far, only two studies on asymmetric organocatalysis achieved by these solvents have been reported. [30,31] Thus, the use of (+)-camphorsulfonic acid (+ CSA) as hydrogen bond donor (HBD) gave liquids at room temperature when mixed with easily one-step synthesized molecules from commercially available compounds (S)-and (R)-N,N,N-trimethyl-(1-phenylethyl)ammonium methanesulfonate, (FR and FS, respectively) as hydrogen bond acceptors (HBAs) (Scheme 9). The two liquids formed by + CSA mixed with the two HBA enantiomers FR and FS were used as green solvents, acid catalysts and chiral organocatalysts in an asymmetric Michael-type Friedel-Crafts addition of indole to chalcone.…”

Probing the structural features and the micro-heterogeneity of various deep eutectic solvents and their water dilutions by the photophysical behaviour of two fluorophores

“…In literature, many cases of acidic catalysis performed by these mixtures are reported, but also other catalytic properties are gaining relevance such as reducing capabilities and also organocatalytic behaviour in asymmetric synthesis (with CDESs: chiral-DESs). In the particular topic of asymmetric catalysis, the properties of the novel liquids revealed to be determined by the intimacy of HBD-HBA couple and therefore on the availability of the organocatalyst in terms of association constant between the two components [26,27]. On the other hand, more structured systems led to higher enantiomeric excesses in the probe reactions thanks to the steric hindrance of one of the two faces of the adducts.…”

Investigation of Base-free Copper-Catalysed Azide–Alkyne Click Cycloadditions (CuAAc) in Natural Deep Eutectic Solvents as Green and Catalytic Reaction Media

“…Recent papers report the acid catalytic behavior, reducing capabilities and also organocatalytic properties of the reaction media itself. [34][35][36][37][38] This is because the properties of the liquids reflect on the properties of the molecules forming them; therefore, the properties of these liquids are tunable.…”

“…The availability of one of the two components to act in a catalytic role is dependent on the "freedom" of one component from the counterpart in the liquid structure; this effect has an impact on the pKa value of acids, that showed different behaviors when mixed in DESs' structures. [34,35,39,40] In this work, it is reported the use of a set of differently structured NADESs as "active" and green reaction media in copper-catalyzed azide-alkyne cycloaddition reactions (CuAAc).…”