THE PREPARATION OF BIS(ETA(3)-ALLYL)IRON(II) COMPLEXES AND THEIR REACTIONS WITH 1,3-DIENES

The title compounds were prepared by treating Fe(PR(3))(2)Cl-2 or Fe(R (2)P(CH2)(n)PR(2))Cl-2 with allylmagnesium chloride. Some of them were also made by reaction of Fe(PR(3))(2)Cl-2 with isopropylmagnesium chl oride, or with active-magnesium and allyl chloride, or by reaction bet ween tris(eta(3)-allyl)iron and bis(dimethylphosphino)ethane. The new compounds were characterized by NMR spectroscopy and shown to be forme d as a mixture of two isomers that differ in the mutual arrangement of the two allyl groups. The reactions of the bis(allyl)iron compounds w ith 1,3-dienes were studied: complexes containing eta(4)-1,3-C4H6, eta (4)-1-C3H5C4H5 or eta(5)-l-ethylcyclohexadienyl groups were isolated f rom the reaction with 1,3-butadiene. The reaction between (eta(3)-C3H5 )(2)Fe((Pr2PC2H4PPr)-Pr-i-Pr-i(2)) and 1,3-cyclohexadiene gave (5)-cyc lohexadienyl)Fe((Pr2PC2H4PPr2)-Pr-i-Pr-i)H.