PyFluor: A Stable Deoxyfluorinating Agent

Pyridine-2-sulfonyl fluoride (PyFluor) is a stable deoxyfluorinating agent wherein the fluorine replaces a free alcohol group via an S_N2 process. For example, PyFluor reacts with primary or secondary alcohols in the presence of DBU to give the corresponding fluorinated products. This fluorination proceeds via intermediate 1 to give the product with stereoinversion. The fluorination of diols bearing secondary and tertiary alcohol parts proceeds at the secondary alcohol part selectively. Furthermore, PyFluor is inactive to carbonyl groups, and no difluorination reaction is observed while conventional fluorinating reagents will typically react with carbonyl groups. It is expected that PyFluor will be used as a fluorinating agent selective for hydroxyl groups.