Preparation of new binaphthol-based tridentate ligands for enantioselective synthesis

A versatile method for resolution of 2,2'-dihydroxy-[1,1'-binaphthalene]-3- carboxylic acid has been developed. Four enantiomerically pure tridentate l igands, namely 3-(hydroxy methyl)[1,1'-binaphthalene]-2,2'-diol (3), 3-[(2- hydroxyethoxy)[1,1'-binaphthalene (4), 3-(2-hydroxy-5-methylbenzyl) [1,1'-b inaphthalene]-2,2'-diol (5), and 3-(2-hydroxy-4,6-di-tert-butylbenzyl)[1, 1 '-binaphthalene]-2, 2'-diol (6), were synthesised in excellent yields and u sed as chiral modifiers of LiAlH4. A modest enantioselectivity was found fo r the reduction of acetophenone with LiAlH4 modified with ligand 4.