Fluorinations of unsymmetrical diaryliodonium salts containing -sidearms; influence of sidearm on selectivity

Activated aromatics were reacted with two different fluoroidoane reagents 1 and 2 in the presence of triflic acid to prepare only the para -substituted diaryliodonium salts. With fluoroiodane 1 the unsymmetrical diaryliodonium salts contained an ortho -propan-2-ol sidearm, whereas the alcohol sidearm was eliminated to form an ortho -styrene sidearm in the reaction with fluoroiodane 2 . Only the diaryliodonium salts containing a styrene sidearm were fluorinated successfully to deliver para -fluorinated aromatics in good yields. Activated aromatics were reacted with a new fluoroiodane reagent to form exclusively the para -substituted diaryliodonium salts containing an ortho -styrene sidearm which were fluorinated successfully to deliver para -fluorinated aromatics.