Formal transfers of hydride from carbon-hydrogen bonds. Synthesis, structure, and reactions of [Cp(CO)2FeCH2]3CH

Article abstract of DOI:10.1021/om00114a018

The reaction of Cp(CO)₂FeNa with (CH₃SO₂OCH₂)₃CH (4) provided [Cp(CO)₂FeCH₂]₃CH (3) in 50% yield. Thermal decomposition of compound 3 occurred rapidly in solution at 25°C and produced approximately equimolar amounts of [Cp(CO)₂Fe]₂ (5) and dicarbonyl(cyclopentadienyl)(cyclopropylmethyl)iron (6). These products presumably result from decarbonylation of compound 3, formation of carbonyl-bridged intermediate 8, and reductive elimination. The reaction of compound 3 with 2 equiv of Ph₃C⁺PF₆^- yielded the Cp(CO)₂Fe⁺ complex 11 of Cp(CO)₂FeCH₂CH₂CH=CH₂ and negligible amounts of triphenylmethane. Ph₃C⁺ may accept an electron from compound 3, triggering loss of Cp(CO)₂Fe* and a shift of Cp(CO)₂FeCH₂ that converts the isobutyl skeleton of the starting material into the n-butyl skeleton of product 11. Irradiation of compound 3 at 350 nm produced [Cp(CO)₂Fe]₂ (5) and an exo/endo mixture of carbonyl(cyclopentadienyl)(η³-2-methyl-2-propenyl)iron (34). These products appear to result from decarbonylation, formation of carbonyl-bridged intermediate 8, further decarbonylation, formation of iron hydride 33 by β-elimination, reductive elimination, and further irradiation of dicarbonyl(cyclopentadienyl)(2-methyl-2-propenyl)iron (21).