FLUORINATION OF CYCLOHEXANOLS WITH 4-MORPHOLINOSULFUR TRIFLUORIDE

Article abstract of DOI:10.1016/S0022-1139(00)82727-X

In contrast to most simple alcohols, cyclohexanol has proved to be a surprisingly difficult compound to fluorinate with aminosulfur trifluorides.In the reaction of 4-morpholinosulfur trifluoride (morpho-DAST) with cyclohexanol, a correlation was found between the polarity index of the solvent, P', and the yield of fluorocyclohexane.In solvents of low polarity, there appears to be an uncharged intermediate that leads to fluorocyclohexane.In solvents of higher polarity, there appears to be a charged intermediate that gives fluorocyclohexane.By a study of the fluorination of cis- and trans-4-tert-butylcyclohexanol, conformational effects were shown to be a major factor in hindering the S_N2 attack by fluoride ion on the reactive intermediate(s).