Catalytic and asymmetric fluorolactonisations of carboxylic acids through anion phase transfer.

Catalytic fluorolactonisations of aromatic carboxylic acids have been developed. The reactions proceed under mild conditions using the commercially available reagent Selectfluor. A weak phase transfer of the reagent mediated by Na2CO3 allows the reaction to be conducted in non-polar solvents. Furthermore, by the use of a catalytic amount of (DHQ)2PHAL (hydroquinine 1,4-phthalazinediyl diether), the first asymmetric fluorolactonisation has been achieved. The corresponding isobenzofuran core can be found in many biologically active molecules.