Resolution of Racemic 1,1'-Bi-2-naphthol Using (S)-Proline via a Cyclic Borate Ester

Article abstract of DOI:10.1016/S0040-4020(99)00085-X

1,1'-Bi-2-naphtholborane generated from racemic 1,1'-bi-2-naphthol and borane dimethyl sulfide complex reacted with (S)-proline in tetrahydrofuran to form a spirocyclic 1,1'-bi-2-naphtholboric proline anhydride. Its two diastereoisomers could be separated efficiently under the experimental conditions, from which enantiomerically pure (R)-(+)- and (S)-(-)-1,1'-bi-2-naphthol were obtained in ca. 80 percent overall yield, respectively. - Keywords: resolution; 1,1'-bi-2-naphthol; (S)-proline; cyclic borate ester.