A new method for recycling chiral bis(oxazoline)-coppercomplexes is described based on the formation of charge-transfercomplexes, their subsequent precipitation, and reuse after addition of new substrates. The conditions to perform this procedure were optimized in the presence of three bis(oxazoline)-based ligands. When associated with copper salts, these ligands efficiently catalyzed the Diels-Alder
An anthracenyl‐modified chiral bis(oxazoline) copper complex has been demonstrated to efficiently promote nitroaldol reactions between structurally varying aldehydes and nitromethane or nitroethane. The catalyst was recovered through formation of a charge transfer complex between the chiral ligand and trinitrofluorenone and its subsequent precipitation with pentane. The efficiency of this procedure
Heterogeneous asymmetric Diels–Alder reactions between cyclopentadiene and 3-but-2-enoyl-oxazolidin-2-one were efficiently promoted by reusable chiral bis(oxazoline)–copper catalysts, immobilized through charge transfer interactions with trinitrofluorenone, that was covalently grafted on Merrifield resins. The modified support was also used for the synthesis of both enantiomers of the target product