The reaction of trichlorosilyltetracarbonyliron hydride (HFe(CO)4SiCl3) with conjugated dienes

Isoprene, 1,3-butadiene and 2,3-dimethyl-1,3-butadiene react with HFe(CO)₄SiCl₃ by addition of the Fe---H function to the diene. Isoprene appears to add predominantly 1,4 and 2,3-dimethyl-1,3-butadiene appears to add 1,2, while 1,3-butadiene may add both ways. In the case of isoprene and 1,3-butadiene loss of CO from the addition compound gives a stable π-allyl- Fe(Co)₃SiCl₃ product. Either cis- or trans-1,3-pentadiene is reduced to pentene by HFe(CO)₄SiCl₃.