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.