Highly selective Friede–Crafts monoacylation of ferrocene catalysed by ytterbium(III) triflate

In the presence of a catalytic amount of ytterbium(III) triflate[Yb(OTf) 3 ], ferrocene reacted with anhydrides or acyl chlorides to afford monoacylferrocenes in high yields under moderate conditions. An efficient, simple and environmentlly friendly procedure was provided. The catalyst was easily recovered and reused without any loss of activity.