Chiral–achiral ligand synergy: activation of a zirconium–BINOL Lewis acid complex by the addition of 4-tert-butylcalix[4]arene
Abstract
4-tert-Butylcalix[4]arene activates the enantioselective allylation of aldehydes catalyzed by a new zirconium–BINOL Lewis acid system allowing the use of less than 2% of the catalyst.