Metal-Catalyzed Benzylic Fluorination as a Synthetic Equivalent to 1,4-Conjugate Addition of Fluoride

We explore in detail the iron-catalyzed benzylic fluorination of substrates containing aromatic rings and electron-withdrawing groups positioned beta to one another, thus providing direct access to beta-fluorinated adducts. This operationally convenient process can be thought of not only as a contribution to the timely problem of benzylic fluorination but also as a functional equivalent to a conjugate addition of fluoride, furnishing products in moderate to good yields and in excellent selectivity.