Effective Way Making Chiral Binol: Resolution

- Jan 12, 2018 -

    Both enantiomers of 1,1'-bi-2-naphthol are widely used for various applications: 1) chiral inducing agents for catalytic, as mmetric reactions such as the Diels-Alder reaction, ene reaction, or as Lewis acids; 2) enantioselective reduction of ketones; 3) synthesis of chiral macrocycles and other interesting compounds. 

    Previously reported resolutions include: 1) making a cyclic phosphate of binaphthol, then resolution and subsequent reduction to release the pure binaphthol; 2) using enzymatic hydrolysis of the diester of binaphthol; and 3) forming inclusion complexes with suitable compounds. The use of N-benzylcinchonidinium chloride to make inclusion complexes was reported by Tanaka and co-workers for obtaining one enantiomer of binaphthol. Using acetonitrile as solvent, in which the inclusion complex has very low solubility, allows for the isolation of both enantiomers with high enantiomeric excess. This simple and efficient procedure represents a much better resolution for 1,1'-bi-2-naphthol.

   UCHEM has been supplying (1,1'-binaphthalene)-2,2'-diol CAS: 602-09-5(R)-(+)-(1,1'-binaphthalene)-2,2'-diol CAS: 18531-94-7(S)-(-)-(1,1'-binaphthalene)-2,2'-diol CAS: 18531-99-2 in large quantity with competitive price.

Organic Syntheses, Coll. Vol. 10, p.93 (2004); Vol. 76, p.1 (1999).