Inexpensive cobalt catalysts with N-heterocyclic carbene ligands enable direct arene alkenylations with easily accessible alkenyl acetates through regioselective C-H/C-O functionalizations in a stereoconvergent fashion. The versatile cobalt catalyst was broadly applicable and thus also allowed for the efficient conversion of alkenyl phosphates, carbonates, and carbamates at ambient temperature.
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http://dx.doi.org/10.1002/anie.201412319 | DOI Listing |
Acc Chem Res
November 2024
State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China.
ACS Catal
July 2024
Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States.
Fe(II) carboxylates react with dioxygen and carboxylic acid to form Fe(μ-OH)(μ-O)(μ-X)(HX) (X = acetate or pivalate), which is an active oxidant for Rh-catalyzed arene alkenylation. Heating (150-200 °C) the catalyst precursor [(η-CH)Rh(μ-OAc)] with ethylene, benzene, Fe(II) carboxylate, and dioxygen yields styrene >30-fold faster than the reaction with dioxygen in the absence of the Fe(II) carboxylate additive. It is also demonstrated that Fe(μ-OH)(μ-O)(μ-X)(HX) is an active oxidant under anaerobic conditions, and the reduced material can be reoxidized to Fe(μ-OH)(μ-O)(μ-X)(HX) by dioxygen.
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April 2024
Departament de Bioquímica i Fisiologia-Secció de Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Avda. Joan XXIII 27-31, 08028 Barcelona, Spain.
An expeditious synthesis of γ- and δ-lactams from tethered alkenyl trichloroacetamides in the presence of 5% of RuCl(PPh) is reported. In this investigation we have demonstrated that microwave activation significantly enhances reaction rates, leading to the formation of the corresponding lactams in yields ranging from good to excellent. Thus, we have been able to prepare a wide range of lactams, including indole and morphan bicyclic scaffolds, where the corresponding reactions were completely diastereoselective.
View Article and Find Full Text PDFOrganometallics
April 2024
Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States.
The Ir(I) complex [Ir(μ-Cl)(coe)] (coe = cyclooctene) is a catalyst precursor for benzene alkenylation using Cu(II) carboxylate salts. Using [Ir(μ-Cl)(coe)], propenylbenzenes are formed from the reaction of benzene, propylene, and CuX (X = acetate, pivalate, or 2-ethylhexanoate). The Ir-catalyzed reactions selectively produce anti-Markovnikov products, -β-methylstyrene, -β-methylstyrene, and allylbenzene, along with minor amounts of the Markovnikov product, α-methylstyrene.
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March 2024
Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 2-12-1-E4-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan.
The carboxylation of unsaturated amine and alcohol compounds, including 4-benzylamino-1-phenyl-1-butyne (homopropargylamine), 2-butyne-1-ol (propargylic alcohol), and 2,3-butadiene-1-ol (allenylmethyl alcohol), using the hydroxidogold(I) complex, AuOH(IPr) [IPr = 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene], produces corresponding alkenylgold(I) complexes with a cyclic urethane or carbonate framework in high yields. The reaction takes place in aprotic THF at room temperature under the atmospheric pressure of CO in the absence of base additives. The products were characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography.
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