Acetyl Hypofluorite, a New Moderating Carrier of Elemental Fluorine and Its Use in Fluorination of 1,3-Dicarbonyl Derivatives

Article abstract of DOI:10.1021/jo00153a021

Elemental fluorine and most of the fluoroxy reagents do not react efficiently or cleanly with 1,3-dicarbonyl derivatives or with their corresponding metal enolates even at -75 degC.It has been found that a suspension of sodium acetate in CFCl3 or in CFCl3-AcOH, when treated with elemental fluorine, forms a new electrophilic fluorinating reagent, CH3COOF (1), which reacts with substrates without further isolation or purification.This reagent is milder than F2, CF3OF, or CF3COOF and reacts successfully where the other reagents fail.When 1 reacts with 1,3-dicarbonyl compounds, the main product is the 1,3-dioxo-2-fluoro derivative in reasonable yields.When, however, the corresponding sodium enolates were treated with 1, the yields of the monofluoro derivatives were considerably higher.In the case of 1,3-dicarbonyl derivatives with low enol content, only the sodium enolates react with 1 to produce good to very good yields of the corresponding 2-monofluoro derivatives.Thus 1 can be considered as a moderating carrier of the highly reactive F2.