Reactions of the thiocarbene complex Cp(CO)2Fe[CH(SMe)]+ with nucleophiles

Article abstract of DOI:10.1021/om50002a014

The thiocarbene complexes Cp(CO)(L)Fe[CH(SMe)]⁺, where L = CO, PPh₃, or P(OPh)₃, are prepared by H^- addition to Cp(CO)(L)Fe[C(SMe)₂]⁺ to give Cp(CO)(L)Fe[CH(SMe)₂], which upon treatment with CF₃SO₃H, HBF₄, or (Ph₃C)PF₆ provides Cp(CO)(L)Fe[CH(SMe)]⁺. Reactions of the electrophilic Cp-(CO)₂Fe[CH(SMe)]⁺ with a range of phosphines and phosphites, L (PPh₂Me, PPh₃, PPh₂Cl, PCl₃, P(OPh)₃, P(OCH₂)₃CMe, PPh₂H, P-c-Hx₂H, PPhH₂, P-c-HxH₂), give the carbene adducts (or ylides) Cp(CO)₂Fe[CH(SMe)(L)]⁺, most of which are air-stable, while the PCl₃ adduct is too unstable to isolate. An X-ray structural determination of Cp(CO)₂Fe[CH(SMe)(P(OCH₂)₃CMe)]PF₆ (monoclinic, P2₁/c, a = 10.359 (3) ?, b = 12.284 (4) ?, c = 16.234 (4) ?, β = 95.25 (3)°, V = 2057 ?³, Z = 4) confirms that the P atom is bonded to the carbene carbon in this and the other adducts. When Cp(CO)₂Fe[CH(SMe)(PPh₃)⁺ is heated at 200°C, Cp(CO)₂Fe(PPh₃)⁺ (88% yield) and cis- and trans-(MeS)CH=CH(SMe) are formed among other products. When Cp(CO)₂Fe[CH(SMe)(PR₂H)]⁺, where R = Ph or c-Hx, is pyrolyzed, rearrangement to the phosphine complex Cp(CO)₂Fe[PR₂(CH₂SMe)]⁺ (20% yield) occurs. The phosphonium proton in Cp(CO)₂Fe[CHSMe)(PPh₂)H)]⁺ is removed by n-BuLi or Et₃N to give Cp(CO)₂Fe[CH(SMe)(PPh₂)], which upon alkylation with MeOSO₂F yields Cp(CO)₂Fe[CH(SMe)(PPh₂Me)]⁺. The carbene ligand in Cp-(CO)₂Fe[CH(SMe)]⁺ reacts rapidly with water to give equal amounts of Cp(CO)₂Fe(CH₂SMe) and CpFe(CO)₃⁺ together with MeSH; deuterium-labeling experimental results are consistent with a mechanism involving a formyl Cp(CO)₂Fe[C(=O)H] intermediate. Diazomethane (CH₂N₂) reacts with Cp(CO)₂Fe[CH(SMe)]⁺ to yield the complex Cp(CO)₂Fe[SMe(CH=CH₂)]⁺ in which the olefin is coordinated to the metal through the S atom.