32005-36-0Relevant articles and documents
Evidence for a Cooperative Mechanism Involving Two Palladium(0) Centers in the Oxidative Addition of Iodoarenes
Perego, Luca Alessandro,Payard, Pierre-Adrien,Haddou, Baptiste,Ciofini, Ilaria,Grimaud, Laurence
, p. 2192 - 2199 (2018)
Oxidative addition of iodoarenes (ArI) to Pd0 ligated by 1-methyl-1H-imidazole (mim) in polar solvents leads to cationic arylpalladium(II) complexes [ArPd(mim)3]+. Kinetic analyses evidence that this reaction is second order with respect to the concentration of Pd0, and a mechanism involving the cooperative intervention of two Pd0 centers has been postulated to explain this finding. This unusual behavior is also observed with other nitrogen-containing ligands and it is general for iodobenzenes substituted with electron-donating or weakly electron-withdrawing groups. In contrast, bromoarenes and electron-poor iodoarenes display first-order kinetics with respect to Pd0. Theoretical calculations performed at the density functional theory (DFT) level suggest the existence of mim-ligated ArI-Pd0 complexes, in which the iodoarene is bound to the metal in a halogen-bond-like fashion. Coordination weakens the C?I bond and facilitates the oxidative insertion of another Pd0 center across this C?I bond. This conceptually novel mechanism, involving the cooperative participation of two distinct metal centers, allows a full explanation of the experimentally observed kinetics.
Synthesis of Indoles by Reductive Cyclization of Nitro Compounds Using Formate Esters as CO Surrogates
Ahmed Fouad, Manar,Ferretti, Francesco,Formenti, Dario,Milani, Fabio,Ragaini, Fabio
supporting information, p. 4876 - 4894 (2021/09/20)
Alkyl and aryl formate esters were evaluated as CO sources in the Pd- and Pd/Ru-catalyzed reductive cyclization of 2-nitrostyrenes to give indoles. Whereas the use of alkyl formates requires the presence of a ruthenium catalyst such as Ru3(CO)12, the reaction with phenyl formate can be performed by using a Pd/phenanthroline complex alone. Phenyl formate was found to be the most effective CO source and the desired products were obtained in excellent yields, often higher than those previously reported using pressurized CO. The reaction tolerates many functional groups, including sensitive ones like a free aldehydic group or a pendant pyrrole. Detailed experiments and kinetic studies allow to conclude that the activation of phenyl formate is base-catalyzed and that the metal doesn't play a role in the decarbonylation step. The reactions can be performed in a single thick-walled glass tube with as little as 0.2 mol-% palladium catalyst and even on a 2 g scale. The same protocol can be extended to other nitro compounds, affording different heterocycles.
A synthesis method according to sets up qu tan hydrobromide
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Paragraph 0050-0052, (2017/10/22)
The invention discloses a synthesis method of eletriptan hydrobromate, which comprises the following steps: reacting (R)-1-acetyl-3-(N-methylpyrrolidinyl-2-methy)-5-bromo-1H-indole and metal in an organic solvent to form a metal complex, reacting the metal complex with a boron reagent in an organic solvent to form aryl borane or aryl borate, carrying out acid-catalyzed hydrolysis to obtain aryl boric acid, and carrying out coupling and hydrolysis on the aryl boric acid and 2-chloroethylphenyl sulfone under the actions of a catalyst and an alkali to obtain eletriptan, or directly carrying out coupling and hydrolysis on the metal complex and 2-chloroethylphenyl sulfone to obtain eletriptan; and carrying out salification on the eletriptan and hydrobromic acid in an organic solvent to finally obtain the eletriptan hydrobromate. The method is simple to operate, has the advantages of high safety, high stability, low cost and higher yield, and is suitable for industrial production.
