Use of readily available chiral compounds related to the Betti base in the enantioselective addition of diethylzinc to aryl aldehydes

Readily available members of the family of chiral non-racemic aminonaphthols related to the Betti base 1 were tested as complexing agents in the catalytic enantioselective addition of diethylzinc to aryl aldehydes. The use of these bases gave high ee values (up to >99%). The highest ee values were obtained with the tertiary aminonaphthol 2. An important role was played by the solvent. The effect of the nature and the position of the substituents on the aromatic ring of the aldehyde was also investigated.