REACTIONS OF [ET3NH][(MU-CO)(MU-RS)FE2(CO)6] COMPLEXES WITH ACETYLENES - SYNTHESIS AND DECARBONYLATION OF ALPHA,BETA-UNSATURATED BRIDGING ACYL COMPLEXES

Reaction of [Et3NH](μ-CO)(μ-RS)Fe2(CO)6] with alkyl- and arylacetylenes (R1C≡CR2) produced neutral μ-vinyl complexes of the type (μ-σ,π-R1C═CHR2)(μ-RS)Fe2(CO)6. Presumably, formation of these products resulted from the in situ protonation of an intermediate vinylic anion by the triethylammonium cation.1H NMR correlations have shown that overall addition of the diiron and proton units has occurred in a cis fashion. In some cases, reaction of [Et3NH][(μ-CO) (μ-RS)Fe2(CO)6] with acetylenes generated the α,β-unsaturated acyl complexes (μ-R2CHC═C(R1)C═O)(μ-RS)Fe2(CO)6 as well. Bridging acyl complexes of this general class were prepared directly by the reactions of α,β-unsaturated acid chlorides R1(R2)C═CHC(O)Cl with [Et3NH][(μ-CO)(μ-RS)Fe2(CO)6]. In refluxing THF, these vinylacyl complexes underwent thermal decarbonylation to the respective μ-vinyl derivatives. © 1990, American Chemical Society. All rights reserved.