923-28-4Relevant academic research and scientific papers
C-H Alkylation of Aldehydes by Merging TBADT Hydrogen Atom Transfer with Nickel Catalysis
Murugesan, Vetrivelan,Ganguly, Anirban,Karthika, Ardra,Rasappan, Ramesh
supporting information, p. 5389 - 5393 (2021/07/21)
Catalyst controlled site-selective C-H functionalization is a challenging but powerful tool in organic synthesis. Polarity-matched and sterically controlled hydrogen atom transfer (HAT) provides an excellent opportunity for site-selective functionalization. As such, the dual Ni/photoredox system was successfully employed to generate acyl radicals from aldehydes via selective formyl C-H activation and subsequently cross-coupled to generate ketones, a ubiquitous structural motif present in the vast majority of natural and bioactive molecules. However, only a handful of examples that are constrained to the use of aryl halides are developed. Given the wide availability of amines, we developed a cross-coupling reaction via C-N bond cleavage using the economic nickel and TBADT catalyst for the first time. A range of alkyl and aryl aldehydes were cross-coupled with benzylic and allylic pyridinium salts to afford ketones with a broad spectrum of functional group tolerance. High regioselectivity toward formyl C-H bonds even in the presence of α-methylene carbonyl or α-amino/oxy methylene was obtained.
C -Methylation of Alcohols, Ketones, and Indoles with Methanol Using Heterogeneous Platinum Catalysts
Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Jamil, Md. A. R.,Toyao, Takashi,Shimizu, Ken-Ichi
, p. 3091 - 3103 (2018/04/14)
A versatile, selective, and recyclable heterogeneous catalytic method for the methylation of C-H bonds in alcohols, ketones, and indoles with methanol under oxidant-free conditions using a Pt-loaded carbon (Pt/C) catalyst in the presence of NaOH is reported. This catalytic system is effective for various methylation reactions: (1) the β-methylation of primary alcohols, including aryl, aliphatic, and heterocyclic alcohols, (2) the α-methylation of ketones, and (3) the selective C3-methylation of indoles. The reactions are driven by a borrowing-hydrogen mechanism. The reaction begins with the dehydrogenation of the alcohol(s) to afford aldehydes, which subsequently undergo a condensation reaction with the nucleophile (aldehyde, ketone, or indole), followed by hydrogenation of the condensation product by Pt-H species to yield the desired product. In all of the methylation reactions explored in this study, the Pt/C catalyst exhibits a significantly higher turnover number than other previously reported homogeneous catalytic systems. Moreover, it is demonstrated that the high catalytic activity of Pt can be rationalized in terms of the adsorption energy of hydrogen on the metal surface, as revealed by density functional theory calculations on different metal surfaces.
A Ruthenium-Grafted Hydrotalcite as a Multifunctional Catalyst for Direct α-Alkylation of Nitriles with Primary Alcohols
Motokura, Ken,Nishimura, Daisuke,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
, p. 5662 - 5663 (2007/10/03)
Treatment of a hydrotacite, Mg6Al2(OH)16CO3, with an aqueous solution of RuCl3·nH2O afforded a monomeric Ru(IV) species on the surface of the hydrotalcite. This novel Ru-grafted hydrotalcite (Ru/HT) efficiently catalyzed α-alkylation of nitriles with primary alcohols through the cooperative catalysis between the Ru species and the surface base sites. The catalyst system could be further extended for the one-pot synthesis of α,α-dialkylated phenylacetonitriles via the base-catalyzed Michael reaction of α-alkylated phenylacetonitrile with activate olefins. Copyright
An Efficient Direct α-Alkylation of Ketones with Primary Alcohols Catalyzed by [Ir(cod)CI]2/PPh3/KOH System without Solvent
Taguchi, Kazuhiko,Nakagawa, Hideto,Hirabayashi, Tomotaka,Sakaguchi, Satoshi,Ishii, Yasutaka
, p. 72 - 73 (2007/10/03)
α-Alkylation of ketones was successfully achieved by the reaction of ketones with alcohols catalyzed by iridium complexes in the presence of a small amount of base. For example, 2-octanone was allowed to react with butanol under the influence of [Ir(cod)Cl]2/PPh3/KOH to give 6-dodecanone in good yield. The reaction was found to proceed by using a 1:1 mixture of ketone and alcohol without use of any solvent. Copyright
Development of new iron catalysts for the tandem isomerization-aldol condensation of allylic alcohols
Uma, Ramalinga,Gouault, Nicolas,Crévisy, Christophe,Grée, René
, p. 6187 - 6190 (2007/10/03)
(bda)Fe(CO)3 and (COT)Fe(CO)3 are shown to be excellent catalysts for the tandem isomerization-aldol reaction of allylic alcohols with aldehydes and to significantly increase the scope of this aldolization process, especially, in the
Efficient isomerization of allylic alcohols to saturated carbonyl compounds by activated rhodium and ruthenium complexes
Uma, Ramalinga,Davies, Maxwell K.,Crevisy, Christophe,Gree, Rene
, p. 3141 - 3146 (2007/10/03)
A range of readily available rhodium complexes of the general structures Rh(PPh3)3+ PF6- and RhX(PPh3)3 (X = H, Me, Ph) have been prepared and used in situ for the isomerization of allylic alcohols to their corresponding saturated carbonyl compounds. The isomerization of octen-3-ol, selected as a model, yielded octan-3-one in good yield. This reaction has been extended to the corresponding ruthenium complexes of the general structures [RuCl(PPh3)3]+ PF6-, RuXCl(PPh3)3 and RuX2(PPh3)3 (X = H, Me, Ph). It is noteworthy that many of these complexes have not been employed previously for this isomerization. The scope and efficiency of the process has been demonstrated by four representative complexes [RhH(PPh3)3, RuH2(PPh3)3, RuPh2(PPh3)3, RuCl(PPh3)3+ PF6-] with a wide variety of allylic alcohols. The reaction of primary allylic alcohols in the presence of RuCl(PPh3)3+ PF6- in methanol yields aldehydes protected as their methyl acetals. Deuterium labelling experiments are in agreement with a 1,3-hydride shift mechanism.
From allylic alcohols to saturated carbonyls using Fe(CO)5 as catalyst: Scope and limitation studies and preparation of two perfume components
Cherkaoui, Hassan,Soufiaoui, Mohammed,Grée, René
, p. 2379 - 2383 (2007/10/03)
The direct conversion of allylic alcohols to saturated carbonyls, using Fe(CO)5 as a catalyst, offers good synthetic potential. Mono-, di- and even trisubstituted alkenes bearing various alkyl, aryl and electronwithdrawing groups on the allylic system give good to excellent yields of rearranged products. Limitations occur mainly with polyunsaturated derivatives. This reaction was applied to a short and efficient synthesis of cyclamen aldehyde and foliaver.
From allylic alcohols to aldols via a novel, tandem isomerization-condensation catalyzed by Fe(CO)5
Crévisy, Christophe,Wietrich, Marina,Le Boulaire, Virginie,Uma, Ramalinga,Grée, René
, p. 395 - 398 (2007/10/03)
Allylic alcohols react with aldehydes, in the presence of catalytic amounts of Fe(CO)5 and under irradiation, to give mainly aldol products. A small amount of ketone resulting from the classical isomerization process is also isolated. This new aldol-type reaction is a complete atom economy process occurring under neutral conditions.
Oxidation of aliphatic alcohols with the lead tetraacetate - Metal halide system under mechanical activation
Kapustina,Sokova,Makhaev,Borisov,Nikishin
, p. 1842 - 1845 (2007/10/03)
The mechanochemical oxidation of n-pentanol, n-hexanol, and n-octanol with the Pb(OAc)4 - MHal system (M = Li, K; Hal = Cl, Br) in the absence of a solvent affords esters, and secondary alcohols with the composition C8H17OH and C9H19OH give ketones.
