Iron-catalysed allylation–hydrogenation sequences as masked alkyl–alkyl cross-couplings

An iron-catalysed allylation of organomagnesium reagents (alkyl, aryl) with simple allyl acetates proceeds under mild conditions (Fe(OAc)(2) or Fe(acac)(2), Et(2)O, r.t.) to furnish various alkene and styrene derivatives. Mechanistic studies indicate the operation of a homotopic catalyst. The sequential combination of such iron-catalysed allylation with an iron-catalysed hydrogenation results in overall C(sp(3))–C(sp(3))-bond formation that constitutes an attractive alternative to challenging direct cross-coupling protocols with alkyl halides.