Molybdenum-Mediated Vinylidene Rearrangement of Internal Acylalkynes and Sulfonylalkynes

Kuwabara, Takuya; Sakajiri, Kousuke; Oyama, Yukiko; Kodama, Shintaro; Ishii, Youichi

doi:10.1021/acs.organomet.9b00019

Cited by 15 publications

(7 citation statements)

References 54 publications

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“…Recently our attention has focused on expanding the scope of the vinylidene rearrangenment from the viewpoints of the reaction site and the group migrating. For the former subject, we have demonstrated that d 6 metal centers such as Ir III and Mo 0 are capable of the 1,2-carbon migration . For the latter, we report herein the vinylidene rearrangement of P- and S-substituted internal alkynes at a ruthenium center, in which the heteroatom substituents are the actual migrating groups, as evidenced by 13 C-labeling experiments.…”

Section: Introductionmentioning

confidence: 79%

Ruthenium Vinylidene Complexes Generated by Selective 1,2-Migration of P- and S-Substituents: Synthesis, Structures, and Dichromism Arising from an Intramolecular CH···O Hydrogen Bond

et al. 2020

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Investigation of the vinylidene rearrangement of phosphorus-and sulfur-substituted internal alkynes at a ruthenium center unveiled selective 1,2-migration of P-and S-substituents and unexpected dichromatic behaviors of a part of the resulting vinylidene complexes. Reactions of [CpRu(dppe)Cl] and R 1 C CR 2 , where R 1 = alkyl, Ar and R 2 = P(O)(OR) 2 , P(O)R 2 , SR, SO 2 R, in the presence of NaBAr F 4 afforded the corresponding vinylidene complexes [CpRu{CC(R 1 )(R 2 )}(dppe)][BAr F 4 ], which were fully characterized by NMR and elemental analysis and, in some cases, X-ray diffraction analysis. 13 C-labeling experiments disclosed selective migration of the P-and Ssubstituents. To our surprise, some of the products displayed dichromatic characters: although solutions of all the vinylidene products are yellow, several products were obtained as yellow and red crystals, others as red-purple crystals, and the rest as yellow crystals. UV−vis absorption spectra for the complexes displaying a dichromatic nature were recorded both in solution and in the solid state. X-ray diffraction analysis revealed that an intramolecular CH•••O hydrogen bond between one of the methylene CH bonds in the dppe ligand and the EO group (E = P, S) is present in the red and the red-purple crystals, which affects the conformation of the vinylidene ligand. In contrast, such hydrogen bonds were not observed in the yellow crystals. Time-dependent density functional theory (TD-DFT) analysis based on the crystal structures revealed that the structural changes of the vinylidene ligand upon the hydrogen bonding account for the dichromism.

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Section: Introductionmentioning

confidence: 79%

Ruthenium Vinylidene Complexes Generated by Selective 1,2-Migration of P- and S-Substituents: Synthesis, Structures, and Dichromism Arising from an Intramolecular CH···O Hydrogen Bond

et al. 2020

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“…Transition metal-mediated heavier vinylidene–heavier alkyne rearrangements as the one proposed herein or vice versa have so far not been observed despite significant progress in the synthesis of isolable heavier vinylidenes ,, and heavier alkynes during the last two decades, although the NHC-mediated 1,2-boryl ligand migration from a digermavinylidene to the unsymmetrical mono NHC-stabilized digermyne in the absence of transition metals has been reported by Aldridge and co-workers . In stark contrast, the transition metal-mediated interconversions of all-carbon alkynes and the corresponding vinylidenes are well-established reactions of considerable preparative use. , …”

Section: Results and Discussionmentioning

confidence: 99%

Transition Metal Complexes of Heavier Vinylidenes: Allylic Coordination vs Vinylidene–Alkyne Rearrangement at Nickel

et al. 2021

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Transition metal π-allyl complexes are key reagents/intermediates of various catalytic and stoichiometric allylation reactions. We now report the first transition metal complex of a heavier allylic π-system. The η 3 -Si 2 Ge allyl nickel complex is formally obtained by the oxidative addition of the Si−Cl bond of the heavier vinylidene [R 2 (Cl)Si−(R)Si(NHC)Ge:] to [Ni(COD) 2 ] (R = 2,4,6triisopropylphenyl; NHC = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene; COD = 1,5-cyclooctadiene). Due to geometric constraints, the coordination to the Ni(II) center occurs through the formal SiGe double bond instead of the residual lone pair of electrons at germanium. In contrast, the Si−N bond of the analogous vinylidene [R 2 (Me 2 N)Si−(R)Si(NHC)Ge:] (obtained by nucleophilic substitution of Cl by NMe 2 ) does not oxidatively add to Ni(0), and a hydridosilagermene-η 2 -nickel complex is obtained instead. The formation of this complex necessarily implies the isomerization of the heavier vinylidene to the corresponding heteroalkyne with the SiGe triple bond in the coordination sphere of nickel followed by the activation of a C−H bond of one of the isopropyl groups of an N-heterocyclic carbene (NHC) ligand.

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“…In most studies on both catalytic and stoichiometric vinylidene rearrangements, terminal alkynes have been used as active substrates due to the high migration ability of a hydrogen atom . Thus, until recently, internal alkynes have found limited use except for several examples using alkoxycarbonyl-, acyl-, silyl-, stannyl-, sulfanyl-, and halogen-substituted internal alkynes. In this context, even unactivated internal alkynes with alkyl or aryl substituents have been demonstrated to participate in vinylidene rearrangements by us and other researchers, and these findings led to the development of novel catalytic alkyne transformations .…”

Section: Introductionmentioning

confidence: 99%

Retro-Vinylidene Rearrangements of P- and S-Substituted Ruthenium Vinylidene Complexes

et al. 2023

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P- and S-substituted vinylidene complexes, [Ru{CC(R)(E)}(dppe)Cp]BArF 4 [E = PO(OMe)2, PO(OEt)2, POPh2, SPh, and SO2Ph], were found to be active for retro-vinylidene rearrangements to add new entries of reversible systems of vinylidene/alkyne isomerization. Isotope labeling experiments revealed that PO(OMe)2- and POPh2-substituted complexes underwent the retro-vinylidene rearrangement via selective 1,2-migration of the P-substituents. In contrast, in the case of a SPh-substituted complex, both the SPh and the R groups served as migrating groups during the reversible alkyne/vinylidene isomerization, though the migration of the SPh group was still the major reaction path. These findings would deepen the mechanistic understanding of alkyne/vinylidene rearrangements of heteroatom-substituted internal alkynes.

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Molybdenum-Mediated Vinylidene Rearrangement of Internal Acylalkynes and Sulfonylalkynes

Cited by 15 publications

References 54 publications

Ruthenium Vinylidene Complexes Generated by Selective 1,2-Migration of P- and S-Substituents: Synthesis, Structures, and Dichromism Arising from an Intramolecular CH···O Hydrogen Bond

Ruthenium Vinylidene Complexes Generated by Selective 1,2-Migration of P- and S-Substituents: Synthesis, Structures, and Dichromism Arising from an Intramolecular CH···O Hydrogen Bond

Transition Metal Complexes of Heavier Vinylidenes: Allylic Coordination vs Vinylidene–Alkyne Rearrangement at Nickel

Retro-Vinylidene Rearrangements of P- and S-Substituted Ruthenium Vinylidene Complexes

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