Benzylideneacetone tricarbonyliron O

Described here is the preparation of (benzylideneacetone ) tricarbonyliron(O) and (l,S-cyclooctadiene)tricarbonyl ruthenium(0). Both compounds function as convenient sources of the metal tricarbonyl moiety by displacement of the organic ligand under mild conditions. 

While a great number of tricarbonyl(i -diene)iron complexes have been reported and their reactivity investigated, much less is known of the corresponding heterodiene complexes. In recent years, synthesis of several tricarbonyl(heterodiene)iron systems involving i coordination of the heterodiene unit has been achieved. Among the tetracarbonyl( f-olefin)iron complexes prepared by Weiss was tetracarbonyl(cinnamaldehyde)iron. 

The complex functions as a convenient source of the tricarbonyliron moiety by displacement of the 0, -unsaturated ketone. For example, reaction with 1,3-cycloheptadiene results in a 78% yield of ( /-l,3-cycloheptadiene) tricarbonyliron. More importantly, it may be used in syntheses of tricarbonyl(diene)iron complexes where the iron carbonyls are not satisfactory. Several complexes of sensitive heptafulvenes have been prepared in this way, and the reagent has been used in the synthesis of tricarbonyliron complexes of several steroids. 

These reactions may be carried out under mild conditions (60°, benzene, 4-8 h) and are clean, in that no colloidal iron or other iron carbonyls are produced. The work-up is thus much easier, and the reactions can be 

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Carbon disulfide complexes of iron 14 are obtained in the reaction of (benzylideneacetone)-tricarbonyliron (o) with P(OMe)3 in carbon disulfide. The complexes react with acetylenes to form iron-carbene complexes 15 ". Depending on the phosphorous ligands, rearrangement to give 16 is observed... 

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