A cationic cobalt catalyst efficiently promoted the reaction of -alkoxycarbonyloxyanilines at 30 °C, affording the corresponding -aminophenols in good to high yields. As reported previously, our mechanistic studies including oxygen-18 labelling experiments indicate that the rearrangement of the alkoxycarbonyloxy group proceeds in [1,3]-manner. In this article, we discuss the overall picture of the cobalt-catalysed [1,3]-rearrangement reaction including details of the reaction conditions and substrate scope.
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http://dx.doi.org/10.3762/bjoc.14.172 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK.
A highly enantioselective cobalt-catalyzed semipinacol rearrangement of symmetric α,α-diarylallylic alcohols is disclosed. A chiral cobalt-salen catalyst generates a highly electrophilic carbocation surrogate following hydrogen atom transfer and radical-polar crossover steps. This methodology provides access to enantioenriched α-aryl ketones through invertive displacement of a cobalt(IV) complex during 1,2-aryl migration.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China.
A cobalt-catalyzed intramolecular Markovnikov hydroalkoxycarbonylation and hydroaminocarbonylation of unactivated alkenes has been developed, enabling highly chemo- and regioselective synthesis of α-alkylated γ-lactones and α-alkylated γ-lactams in good yields. The mild reaction conditions allow use of mono-, di- and trisubstituted alkenes bearing a variety of functional groups. Preliminary mechanistic studies suggest the reaction proceeds through a CO-mediated hydrogen atom transfer (HAT) and radical-polar crossover (RPC) process, in which a cationic acylcobalt(IV) complex is proposed as the key intermediate.
View Article and Find Full Text PDFJ Am Chem Soc
March 2024
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States.
Even though metal-catalyzed enantioselective hydroborations of alkenes have attracted enormous attention, few preparatively useful reactions of α-alkyl acrylic acid derivatives are known, and most use rhodium catalysts. No examples of asymmetric hydroboration of the corresponding α-arylacrylic acid esters are known. In our continuing efforts to search for new applications of earth-abundant cobalt catalysts for broadly applicable organic transformations, we have identified 2-(2-diarylphosphinophenyl)oxazoline ligands and mild reaction conditions for efficient and highly regio- and enantioselective hydroboration of α-alkyl- and α-aryl- acrylates, giving β-borylated propionates.
View Article and Find Full Text PDFChem Commun (Camb)
January 2024
Université Paris-Saclay, CEA, CNRS, NIMBE, Gif-sur-Yvette 91191, France.
We describe the synthesis and characterisation of four organic Lewis acids based on fluorophosphoniums, with tetracarbonyl cobaltate as the counter-anion: [RPF][Co(CO)] (with R = -Tol, Cy, Pr, and Bu). Their catalytic activity was investigated for the carbonylation of β-lactones to succinic anhydrides. In the presence of [BuPF][Co(CO)] IV (3 mol%), 90% of succinic anhydride was afforded from β-propiolactone after 16 h at 80 °C, at a very mild pressure of 2 bar of carbon monoxide.
View Article and Find Full Text PDFACS Omega
July 2023
ZhengZhou JiShu Institute of AI Science, Zhengzhou, Henan 451162, P. R. China.
Organosilicon and organotin compounds have been widely used in many fields, such as organic synthesis, materials science, and biochemistry, because of their unique physical and electronic properties. Recently, two novel compounds containing C-Si or C-Sn bonds have been synthesized. These compounds can be used for late modification of drug-like molecules such as probenecid, duloxetine, and fluoxetine derivatives.
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