Selective Dimerization of Alkyl Crotonates Catalyzed by Iron(0) Complexes Having 1,2-Bis(dimethylphosphino)ethane Ligands

Abstract

Highly selective dimerization of alkyl crotonates has been performed in the presence of a catalytic amount of FeHNp(dmpe)2 or FeH2(dmpe)2/UV irradiation at room temperature.

Iron-catalysed alkene and heteroarene H/D exchange by reversible protonation of iron-hydride intermediates

“…Control reactions ruled out any acid- or base-mediated isomerisation. The aforementioned observations, alongside previous work, 5 b ,27 would suggest that the deuteration of alkenes is occurring through a combination of (direct) C–H metallation and hydrometallation mechanisms, with the latter observed to mediate alkene isomerisation alongside exchange (Scheme 4).…”

Catalytic Dimerization of Crotonates

“…This reaction represents a particularly mild and rapid conversion of a C9 feedstock to a C18 product (Scheme ). Although I i Pr 2 Me 2 is quite effective, the use of catalytic KO t Bu provides an operationally straightforward and facile strategy for these dimerization reactions that is a considerable improvement over previous literature reports. − …”

“…6 12 Fe catalysts, such as 1−5 mol % of FeH 2 (dmpe) 2 /hν or FeNpH(dmpe) 2 (dmpe = 1,2-bis(dimethylphosphino)ethane, Np = 2-naphthyl) generate (E)-2-ethylidene-3-methylpentanedioates selectively with yields of 73−95% in neat crotonate at room temperature. 13 Herein, we report two facile and selective dimerization reactions of crotonates and alkenoates to 2-alkylidene-3-alkylpentanedioates eq 1.…”

“…The dimerization of ethyl crotonate with 22 mol % [NBu 4 ]­[SiPh 3 F 2 ] in THF at room temperature afforded a 74% yield of ethyl 2-ethylidene-3-methylpentanedioate after 2 h, but dimerization with P­[N­(CH 3 ) 2 ] 3 required more forcing conditions (300 MPa, 50 °C, 24 h) . Fe catalysts, such as 1–5 mol % of FeH 2 (dmpe) 2 / h ν or FeNpH­(dmpe) 2 (dmpe = 1,2-bis­(dimethylphosphino)­ethane, Np = 2-naphthyl) generate ( E )-2-ethylidene-3-methylpentanedioates selectively with yields of 73–95% in neat crotonate at room temperature . Herein, we report two facile and selective dimerization reactions of crotonates and alkenoates to 2-alkylidene-3-alkylpentanedioates eq . …”

Iron Dihydride Complexes: Synthesis, Reactivity, and Catalytic Applications

“…A report by Komiya et al. showed that under UV irradiation cis ‐(dmpe) 2 FeH 2 catalyzed selective dimerization of methyl crotonate (Figure , eq 1) . Similar reactions with methyl acrylate and methyl methacrylate failed, which was attributed to the poor activity of hydridoalkenyl species resulting from C−H bond activation.…”