METHOD FOR PREPARING DIFUNCTIONAL COMPOUNDS HAVING HIGH ENANTIOMERIC PURITY

PCT No. PCT/FR94/00673 Sec. 371 Date Mar. 4, 1996 Sec. 102(e) Date Mar. 4, 1996 PCT Filed Jun. 8, 1994 PCT Pub. No. WO94/29253 PCT Pub. Date Dec. 22, 1994A process for preparing a difunctional compound having high enantiomeric purity that is a 1,2-, 1,3-, or 1,4-diol, dithiol, or mercapto alcohol from an optically active starting material that includes an alpha -, beta -, or gamma -hydroxy (or mercapto) aldehyde, ketone, ester, or amide is described. The process is carried out in an anhydrous solvent medium and comprises (1) reducing the starting material with a metal hydride (e.g., sodium borohydride), (2) adding a coreactant that is substituted by at least one, but preferably two, hydroxyl or mercapto groups (e.g., pyrocatechol), and (3) directly distilling the product from the reaction medium. The coreactant preferably has a higher boiling point at normal atmospheric pressure than the difunctional compound. The difunctional compounds are used as reactants for syntheses of agrochemicals or pharmaceuticals, or as precursors for polymers.