Dual stereoselection in the addition of diethylzinc to benzaldehyde by using highly structurally close ligands

The screening of the catalytic activity in the diethylzinc reaction of a series of easily accessible (1S)-ketopinic-acid derived hydroxyamides, designed by key structure modifications of a parent highly active related bis(hydroxyamide), has allowed to find the first case of dual stereoselection in highly structurally close ligands of such interesting chemically sustainable typology. The found striking dual stereoselection is explained on the basis of empiric models for the acting zinc catalysts and involved controlling transition states, which are supported by additional specific experimental structure-activity tests.