6957-09-1Relevant academic research and scientific papers
The Barbier-Grignard-Type Arylation of Ketones and Unexpected Cross-Coupling of Phenolic Ketones using Unactivated Aryl Bromides
Wen, Yunming,Chen, Guifang,Huang, Shiqiang,Tang, Yu,Yang, Jun,Zhang, Yuanming
, p. 947 - 957 (2016/04/05)
A novel, highly versatile and efficient method has been developed for the Barbier-Grignard-type arylation of ketones and an unexpected cross-coupling of phenolic ketones was observed using unactivated bromides and magnesium in tetrahydrofuran/toluene at 96°C promoted by multicatalysts of cupric bromide (15 mol%), bismuth chloride (5 mol%) and silver bromide (10 mol%). The substituent and electronic effects on the reaction have been discussed. High yields of arylation and cross-coupling have been attained under mild conditions. A novel reasonable mechanism involving a quinone intermediate is proposed. The high chemical selectivity in the cross-coupling to the hydroxy group of phenolic ketones should help ketones find new applications.
Iodine-Promoted Metal-Free Aromatization: Synthesis of Biaryls, Oligo p-Phenylenes and A-Ring Modified Steroids
Domingo, Victoriano,Prieto, Consuelo,Castillo, Alexis,Silva, Lucia,Quílez Del Moral, José F.,Barrero, Alejandro F.
supporting information, p. 3359 - 3364 (2015/11/03)
We describe efficient procedures based on the use of iodine for the synthesis of biaryls from arylcyclohexenols or arylcyclohexanols using sub-stoichiometric/catalytic iodine and dimethyl sulfoxide (DMSO) as oxidant. Heteroarylcyclohexanols also produced the corresponding biaryl products. It was proven that biphenyl can also be efficiently obtained when the quantity of iodine was reduced to 0.05 equiv. The method is compatible with different functional groups in the aromatic ring (either electron-donating or electron-withdrawing groups). For substrate scope, apart from cyclohexanone and cyclohexenone, some substituted cyclohexanones were also used to synthesize the starting arylcyclohexanols. The process was applied to the synthesis of oligo p-phenylenes and A-ring aromatized steroids, where the combined use of I2/DMSO not only provoked the necessary migration of the methyl group at C-10, but also further extended the conjugation.
Enantioselective photoredox catalysis enabled by proton-coupled electron transfer: Development of an asymmetric aza-pinacol cyclization
Rono, Lydia J.,Yayla, Hatice G.,Wang, David Y.,Armstrong, Michael F.,Knowles, Robert R.
supporting information, p. 17735 - 17738 (2014/01/06)
The first highly enantioselective catalytic protocol for the reductive coupling of ketones and hydrazones is reported. These reactions proceed through neutral ketyl radical intermediates generated via a concerted proton-coupled electron transfer (PCET) event jointly mediated by a chiral phosphoric acid catalyst and the photoredox catalyst Ir(ppy)2(dtbpy)PF6. Remarkably, these neutral ketyl radicals appear to remain H-bonded to the chiral conjugate base of the Bronsted acid during the course of a subsequent C-C bond-forming step, furnishing syn 1,2-amino alcohol derivatives with excellent levels of diastereo- and enantioselectivity. This work provides the first demonstration of the feasibility and potential benefits of concerted PCET activation in asymmetric catalysis.
Ni-catalysed, domino synthesis of tertiary alcohols from secondary alcohols
Berini, Christophe,Navarro, Oscar
supporting information; experimental part, p. 1538 - 1540 (2012/02/16)
The use of in situ generated (NHC)-Ni catalytic species (NHC = N-heterocyclic carbene) allows for the synthesis, in short reaction times, of a variety of tertiary alcohols from secondary alcohols through a domino oxidation-addition protocol.
Preparation of α,n-dilithiotoluene equivalents. Synthesis of tamoxifen
Yus, Miguel,Ramón, Diego J.,Gómez, Inmaculada
, p. 3219 - 3225 (2007/10/03)
The successive reaction of chlorobenzyl alcohols with n-butyllithium and lithium powder in the presence of a substoichiometric amount of 4,4′-di-tert-butylbiphenyl (DTBB) at -78°C yields the expected (lithiooxymethyl)phenyllithium derivative, which is trapped by reaction with different ketones. The subsequent arene-catalysed lithiation at 25°C permits the one-pot chemoselective lithiation of the primary benzyl alcoholate in the presence of a tertiary one. These new functionalised benzyllithium derivatives react with different electrophilic compounds, such as aldehydes, ketones and chlorotrimethylsilane, to give after hydrolysis the expected functionalised benzyl alcohols. Some of these alcohols are successfully transformed into mono- or di-olefins by acidic treatment. This whole strategy is applied to the preparation of anti-cancer drug tamoxifen.
Electroreductive coupling of organic halides with aldehydes catalyzed by nickel(0) complex with 2,2′-bipyridine
Budnikova,Keshner,Kargin
, p. 453 - 456 (2007/10/03)
A method of electrosynthesis of secondary alcohols from aldehydes and organic halides under the action of nickel(0) complexes is proposed. The key stage is addition of σ-complex RNi(I)bipy (bipy is 2,2′-bipyridine) to the aldehyde group.
Synthesis and Anticonvulsant Activity of 1-Phenylcyclohexylamine Analogues
Thurkauf, Andrew,Costa, Brian de,Yamaguchi, Shun-ichi,Mattson, Mariena V.,Jacobson, Arthur E.,et al.
, p. 1452 - 1458 (2007/10/02)
Thirty-eight analogues of 1-phenylcyclohexylamine (PCA), a phencyclidine (PCP) derivative, were examined for their activities in the mouse maximal electroshock (MES) seizure test and in a motor-toxicity assay.In addition, we determined the binding affinities of the compounds for PCP acceptor sites in rat brain membranes labeled with -1-piperidine.Many of the analogues were protective against MES seizures (ED50s of 4-41 mg/kg, ip) and all of these compounds caused motor toxicity.The potencies in the motor toxicity and MES seizure tests showed a moderate correlation with the affinities for PCP sites.Several analogues exhibited a greater separation of potencies in the motor toxicity and MES seizure tests than did the parent compound PCA.These were obtained by (i) 3-methylation of the cyclohexyl ring trans to the phenyl ring, (ii) methoxylation at the ortho position on the phenyl ring, and (iii) contraction of the cyclohexane ring to form the corresponding cyclopentane.
