A FACILE GENERAL-ROUTE TO ENANTIOMERIC 1-(4-HYDROXYPHENYL)ALKANOLS, AND AN IMPROVED SYNTHESIS OF 4-VINYLPHENOL

Optically pure 1-(4-hydroxphenyl)alkanols, the phenolic hydroxy groups of which are protected, have been obtained by an improved resolution procedure. Since subsequent deprotection of these is accompanied by complete elimination to the phenolic styrenes, an efficient synthesis of 4-vinylphenol from the racemic protected alcohols by simultaneous deprotection and elimination at 0-degrees-C has been developed. The target chiral 1-(4-hydroxphenyl)alkanols have been prepared by treatment of the O-protected 4-hydroxphenyl alkyl ketone with the enantiomers of chlorodiisopinocampheylborane at 0-degrees-C, when asymmetric reduction and simultaneous deprotection gives the enantiomeric diols in > 99.7% e.e. and high chemical yield.