65001-62-9Relevant academic research and scientific papers
Photochemical Activation of Aromatic Aldehydes: Synthesis of Amides, Hydroxamic Acids and Esters
Nikitas, Nikolaos F.,Apostolopoulou, Mary K.,Skolia, Elpida,Tsoukaki, Anna,Kokotos, Christoforos G.
supporting information, p. 7915 - 7922 (2021/05/03)
A cheap, facile and metal-free photochemical protocol for the activation of aromatic aldehydes has been developed. Utilizing thioxanthen-9-one as the photocatalyst and cheap household lamps as the light source, a variety of aromatic aldehydes have been activated and subsequently converted in a one-pot reaction into amides, hydroxamic acids and esters in good to high yields. The applicability of this method was highlighted in the synthesis of Moclobemide, a drug against depression and social anxiety. Extended and detailed mechanistic studies have been conducted, in order to determine a plausible mechanism for the reaction.
On the Virtue of Indium in Reduction Reactions. A Comparison of Reductions Mediated by Indium and Zinc: Is Indium Metal an Effective Catalyst for Zinc Induced Reductions?
Matassini, Camilla,Bonanni, Marco,Marradi, Marco,Cicchi, Stefano,Goti, Andrea
supporting information, p. 1106 - 1113 (2019/12/24)
Indium(0)-mediated reductions have been reported for the transformation of several functional groups (imines, oximes, nitro groups, isoxazolidines, and conjugated alkenes, among others), prompted by the opportunity of performing the reactions in aqueous media and green conditions. We describe here the comparison of several reactions using indium or the less expensive zinc, carried out in order to evaluate the effective advantages brought about indium metal. We found some reactions for which use of In is mandatory and others where Zn worked equally well or even better. The reduction of hydroxylamines to the corresponding amines was the only reduction for which use of In provided much better results than Zn and was also possible to apply an efficient catalytic version with use of 2–5 mol-% In in the presence of stoichiometric Zn. Applicability of this catalytic reduction to “one-pot” model processes is also demonstrated.
Cobalt-Catalyzed Allylic Alkylation Enabled by Organophotoredox Catalysis
Takizawa, Koji,Sekino, Tomoyuki,Sato, Shunta,Yoshino, Tatsuhiko,Kojima, Masahiro,Matsunaga, Shigeki
supporting information, p. 9199 - 9203 (2019/06/04)
Co-catalyzed allylic substitution reactions have received little attention, arguably because of the lack of any known advantage of Co catalysis over either Rh or Ir catalysis. Described here is a general and regioselective Co-catalyzed allylic alkylation using an in situ catalyst activation by organophotoredox catalysis. This noble-metal-free catalytic system exhibits unprecedentedly high reactivities and regioselectivities for the allylation with an allyl sulfone, for the first time, representing the unique synthetic utility of the Co-catalyzed method compared to the related Rh- and Ir-catalyzed reactions.
Derivatization of secondary aliphatic alcohols to picolinates - A new option for HPLC analysis with chiral stationary phase
Nishimura, Keita,Tanabe, Shuhei,Shinohara, Riku,Kobayashi, Yuichi
, p. 273 - 282 (2019/04/27)
Derivatization of secondary alcohols (R1R2CHOH) to benzoates has frequently employed to determine enantiomer ratios using HPLC with chiral stationary phase (CSP). However, a small difference in substituents (R1, R2) often results in insufficient separation. To find an alternative derivatization that detects such a small difference, picolinates (2-pyridyl-CO2CHR1R2) possessing Me/Et, Me/vinyl, Me/acetylenic, Et/n-Pr, and n-Pr/allyl substituents were prepared and separation efficiency was compared with that of benzoates (PhCO2CHR1R2). Eight commercially available CSPs containing carbamates or benzoates of cellulose and amylose were examined to find that retention factors (k'1 and k'2) and resolution (Rs) of picolinates were greater than those of the corresponding benzoates and that good to excellent Rs values (≥1.25) were recorded over a wide range of CSPs.
Selective catalytic oxidation of alcohols, aldehydes, alkanes and alkenes employing manganese catalysts and hydrogen peroxide
Saisaha, Pattama,Buettner, Lea,Van Der Meer, Margarethe,Hage, Ronald,Feringa, Ben L.,Browne, Wesley R.,De Boer, Johannes W.
supporting information, p. 2591 - 2603 (2013/10/21)
The manganese-containing catalytic system [MnIV,IV 2O3(tmtacn)2]2+ (1)/carboxylic acid (where tmtacn=N,N′,N′′-trimethyl-1,4,7-triazacyclononane), initially identified for the cis-dihydroxylation and epoxidation of alkenes, is applied for a wide range of oxidative transformations, including oxidation of alkanes, alcohols and aldehydes employing H2O2 as oxidant. The substrate classes examined include primary and secondary aliphatic and aromatic alcohols, aldehydes, and alkenes. The emphasis is not primarily on identifying optimum conditions for each individual substrate, but understanding the various factors that affect the reactivity of the Mn-tmtacn catalytic system and to explore which functional groups are oxidised preferentially. This catalytic system, of which the reactivity can be tuned by variation of the carboxylato ligands of the in situ formed [MnIII,III 2(O)(RCO2)2(tmtacn)2]2+ dimers, employs H2O2 in a highly atom efficient manner. In addition, several substrates containing more than one oxidation sensitive group could be oxidised selectively, in certain cases even in the absence of protecting groups. Copyright
Palladium-catalyzed selective anti-markovnikov oxidation of allylic esters
Dong, Jia Jia,Fananas-Mastral, Martin,Alsters, Paul L.,Browne, Wesley R.,Feringa, Ben L.
supporting information, p. 5561 - 5565 (2013/06/27)
An aldol alternative: The palladium(II)-catalyzed anti-Markovnikov oxidation of allylic esters to aldehydes at room temperature provides a viable alternative to valuable cross aldol products. High regioselectivity towards the aldehyde product was achieved using the ester protecting group for the allylic alcohol. Rapid isomerization and the much higher rate of oxidation of the branched isomer result in the same product forming from both linear and branched allylic esters. Copyright
[Pd(μ-Br)(PtBu3)]2 as a highly active isomerization catalyst: Synthesis of enol esters from allylic esters
Mamone, Patrizia,Gruenberg, Matthias F.,Fromm, Andreas,Khan, Bilal A.,Goossen, Lukas J.
, p. 3716 - 3719 (2012/09/08)
The dimeric Pd(I)-complex [Pd(μ-Br)(PtBu3)] 2 was found to be highly active for catalyzing double-bond migration in various substrates such as unsaturated ethers, alcohols, amides, and arenes, under mild conditions. It efficiently mediates the conversion of allylic esters into enol esters, rather than inserting into the allylic C-O bond. The broad applicability of this reaction was demonstrated with the synthesis of 22 functionalized enol esters.
Esters as acylating reagent in a Friedel-Crafts reaction: Indium tribromide catalyzed acylation of arenes using dimethylchlorosilane
Nishimoto, Yoshihiro,Babu, Srinivasarao Arulananda,Yasuda, Makoto,Baba, Akio
supporting information; experimental part, p. 9465 - 9468 (2009/04/06)
(Chemical Equation Presented) The Friedel-Crafts acylation of arenes with esters by dimethylchlorosilane and 10 mol % of indium tribromide has been achieved. The key intermediate RCOOSi(Cl)Me2 is generated from alkoxy esters with the evolution of the corresponding alkanes. The scope of the alkoxy ester moiety was wide: tert-butyl, benzyl, allyl, and isopropyl esters were successful. In addition, we demonstrated the direct synthesis of the indanone intermediate 11 of salviasperanol from ester 10.
Copper catalyzed asymmetric synthesis of chiral allylic esters
Geurts, Koen,Fletcher, Stephen P.,Feringa, Ben L.
, p. 15572 - 15573 (2007/10/03)
The complex derived from Taniaphos ligand 4 and CuBr?Me2S catalyzes the asymmetric addition of Grignard reagents to 3-bromopropenyl esters 1 to provide allylic esters 2 in high yields and high chemio-, regio-, and enantioselectivities. The work demonstrates that allylic asymmetric alkylation (AAA) can be done on substrates bearing a heteroatom at the γ-position. The method is a practical route to chiral, nonracemic allylic alcohols. The use of functionalized substrates 1 or Grignard reagents leads to more complex products 2, which can be further manipulated as demonstrated in conversion to (S)-5-ethyl-2(5H)-furanone 6 and (S)-benzoic acid-cyclopent-2-enyl ester 7. Copyright
Kinetic resolution and unusual regioselectivity in palladium-catalyzed allylic alkylations with a chiral P,S ligand
Faller,Wilt, Jeremy C.,Parr, Jonathan
, p. 1301 - 1304 (2007/10/03)
Effective kinetic resolutions of acyclic allylic acetates and benzoates have been obtained using a palladium/(S)-BINAP(S) catalyst system. Unusually large preferences for the formation of branched alkylation products from 3-but-2-enyl and crotyl substrate
