Synthesis of 1,2- and 1,4-disubstituted Tricarbonyl(pentadienyl)iron(+1) Cations and Reactions with Heteroatom Nucleophiles
American Chemical Society
Tricarbonyl(l,2-dimethylpentadienyl)iron(+1) (3a), tricarbonyl(2-methyl- 1-phenylpentadienyl)iron(+l) (3b), tricarbonyl(l,4-dimethylpentadienyl)iron(+l) (4a), and tricarbonyl(4-methyll-phenylpentadienyl)iron(+l) (4b) were prepared as their hexafluorophosphate salts by the dehydration of the appropriately substituted dienol complexes. The reaction of each cation with methanol and with triphenylphosphine proceeds with excellent regioselectivity to afford the corresponding methyl ethers and phosphonium salts, respectively. The reduction of each cation with sodium cyanoborohydride was also examined. Only for cation 3b was good regioselectivity observed; the other cations gave mixtures of diene complexes.