The resolution of 2-chlorofluoren-9-ol and the preparation of (+)- and (–)-2,9-dichlorofluorene, (+)-9-bromo-2-chlorofluorene, and the corresponding racemic compounds

Abstract

2-Chlorofluoren-9-ol has been resolved by fractional crystallisation of the ephedrine salt of its hydrogen phthalate. The conversion of (+)- or (–)-2-chlorofluoren-9-yl hydrogen phthalate into 2-chlorofluorenol with methylmagnesium iodide occurred with retention of configuration, whereas solvolysis yielded completely or largely racemised material, and reduction with lithium aluminium hydride yielded partially racemised material. (+)- and (–)-2,9-Dichlorofluorene, (+)-9-bromo-2-chlorofluorene, and the corresponding racemic compounds have been prepared.