FeCl3·6H2O-catalyzed selective reduction of allylic halides to alkenes with concomitant oxidation of benzylic alcohols to aldehydes

Iron-catalyzed direct reduction of allylic halides with benzylic alcohol was achieved, providing a new, simple, and efficient method for conducting highly regioselective hydrodehalogenation. This method not only features a readily available reductant, an inexpensive catalyst, simple manipulation, and good tolerance of functional groups including nitriles, nitro, esters, and methoxyl groups, it also has mild reaction conditions and shows complete regioselectivity in that only halides sited at the allylic position are reduced. Alternatively, this method can be applied in the selective transformation of benzylic alcohols to aromatic aldehydes without overoxidation to carboxylic acids.