Bifunctional Binols: Chiral 3,3'-Bis(aminomethyl)-1,1'-bi-2-naphthols (Binolams) in asymmetric catalysis

Abstract

3,3'-Bis(dialkylaminomethyl)-1,1'-binaphth-2-ols (Binolams) have emerged during the last five years as very efficient chiral ligands in many enantioselective processes. Enantiomerically pure Binolams are easily accessible by means of a variety of methods, the most widely used being the so-called chiral Binol route. In most cases, Binolam-metal complexes behave as bifunctional catalysts: that is, they are characterized by their dual action on the reagents, being able to activate both the nucleophilic and the electrophilic species involved in the reaction. The most successful transformations carried out with complexes of this type include cyanation of aldehydes and ketones and enantioselective nucleophilic additions of enolate derivatives and organometallic compounds to C=O or C=N double bonds. As a final bonus, the basic natures of these ligands allow their recovery in high yields in numerous transformations.