Natural Eutecto gels: Sustainable Catalytic Systems for C-C Bond Formation Reactions

Abstract

Natural eutecto gels were prepared combining properties of amino acids with the ones of deep eutectic solvents. Soft materials obtained were fully characterised determining the gel-sol transition temperatures and analysing mechanical and morphological features through rheological measurements and polarised optical microscopy. All eutecto gels were tested as catalytic reaction media for the enantioselective aldol reaction and, the best performing one was also used to carry out the Michael addition. In both cases, eutecto gels proved to have a great potential as sustainable reaction media, allowing to perform processes under mild conditions, obtaining excellent yields and, in some cases, also good enantiomeric excess. Catalytic soft materials can be reused up to five cycles keeping the stereochemical control of the reaction and using a recommended solvent by recent sustainable solvent guidelines.