Organic transformations catalyzed by gold nanoparticles incarcerated in a nanoporous polymer matrix

Gold nanoparticles (AuNPs) are emerging as a powerful tool in sustainable catalysis. When synthesized of appropriate dimension (1-​10nm) and adequately supported on a variety of inorg. compds., the AuNPs efficiently catalyze a no. of org. redox reactions under green and mild conditions. Recently org. polymers (as e.g. PVP, PS, PEG, PVA) have been alternatively exploited for stabilizing gold colloids; the polymer supports allow a fine tuning of the chem. and phys. environment of the bare particles, good swelling of the gold catalyst in a variety of solvents and permit reaching unprecedented selectivity in aerobic oxidn. of alcs. under very mild reaction conditions. We have recently found that AuNPs stabilized by a cryst. nanoporous polystyrenic matrix (AuNPs-​sPSB) efficiently catalyze the aerobic oxidn. of a variety of benzyl and allyl alcs. using oxygen as oxidant and water as solvent, whereas aliph. alcs. resulted not reacted under the mild reaction conditions employed. This selectivity was successfully addressed for the direct oxidative esterification of cinnamyl alc. with alkyl alcs. Under appropriate reaction conditions the oxidative cleavage of the carbon-​carbon double bonds was obsd. and investigated. The formation of epoxy intermediate species was demonstrated and recognized as the rate detg. step. The aerobic oxidative esterification of HMF with alkyl alcs. to yield dialkyl 2,​5-​furanoates was similarly investigated and the main results will be discused.