20619-23-2Relevant articles and documents
Solid Superbase-Catalyzed Stereoselective 1,4-Addition Reactions of Simple Amides in Batch and Continuous-Flow Systems
Borah, Parijat,Yamashita, Yasuhiro,Kobayashi, Shū
, p. 3807 - 3812 (2019)
The utilization of a catalytic solid superbase in fine synthesis is challenging. Here, we employed K/γ-Al2O3 catalytically as a highly efficient solid superbase to perform direct 1,4-addition reactions of simple amides with α,β-unsaturated carbonyls. The desired 1,5-dicarbonyl compounds were obtained in high yields with excellent anti-diastereoselectivities. K/γ-Al2O3 showed a Hammett basicity of 37>H_≥35. The solid base was characterized by using TGA-DTA, 27Al solid-state NMR spectroscopy, and XPS to determine the origin of the superbasicity. Continuous-flow synthesis of a 1,5-dicarbonyl compound was demonstrated by using the novel solid superbase-catalyzed 1,4-addition methodology. We have also uncovered the potential of K/γ-Al2O3 in asymmetric 1,4-addition reactions. (Figure presented.).
Metal-free n -arylation of secondary amides at room temperature
Tinnis, Fredrik,Stridfeldt, Elin,Lundberg, Helena,Adolfsson, Hans,Olofsson, Berit
, p. 2688 - 2691 (2015/06/16)
The arylation of secondary acyclic amides has been achieved with diaryliodonium salts under mild and metal-free conditions. The methodology has a wide scope, allows synthesis of tertiary amides with highly congested aryl moieties, and avoids the regioselectivity problems observed in reactions with (diacetoxyiodo)benzene.
Visible light photoredox-catalysed intermolecular radical addition of α-halo amides to olefins
Nakajima, Masaki,Lefebvre, Quentin,Rueping, Magnus
supporting information, p. 3619 - 3622 (2014/04/03)
We present α-chloro amides as a new class of α-acetyl radical precursors, which undergo a tin-free, photoredox-catalysed intermolecular α-alkylation with various olefins exclusively in an anti-Markovnikov fashion. The reaction represents a reductive atom
Insertion of benzene rings into the amide bond: one-step synthesis of acridines and acridones from aryl amides
Pintori, Didier G.,Greaney, Michael F.
supporting information; experimental part, p. 168 - 171 (2010/03/30)
"Chemical Equation Presented" Insertion of benzene rings into the amide bond using the reactive intermediate benzyne is described. Aromatic amides undergo smooth insertion when treated with O-triflatophenyl silane benzyne precursors, producing versatile a
Synthesis of indolones via radical cyclization of N-(2-halogenoalkanoyl)- substituted anilines
Nishio, Takehiko,Iseki, Kyoko,Araki, Norihito,Miyazaki, Takenori
, p. 35 - 41 (2007/10/03)
The radical reactions of N-(2-halogenoalkanoyl)-substituted anilines (anilides) of type 1 have been investigated under various conditions. Treatment of compounds 1a-1o with Bu3SnH in the presence of (2,2′-azobis(isobutyronitrile) (AIBN) afforded a mixture of the indolones (oxindoles) 2a-2o and the reduction products 5a-5o (Table 1). In contrast, the N-unsubstituted anilides 1p-1s, 1u, and 1v gave the corresponding reduction products exclusively (Table 1). Similar results were obtained by treatment of 1 with Ni powder (Table 2) or wth Et3B (Table 3). Anilides with longer N-(phenylalkyl) chains such as 6 and 7 were inert towards radical cyclization, with the exception of N-benzyl-2-bromo-N,2-dimethylpropanamide (6b), which, upon treatment with Ni powder in i-PrOH, afforded the cyclized product 9b in low yield (Table 4). Upon irradiation, the extended anilides 6, 7, 10, and 11 yielded the corresponding dehydrobromination products exclusively (Table 5).
Oxidative rearrangement of ketimines to amides by MCPBA and BF3·OEt2
Kim, So Yeon,An, Gwang-Il,Rhee, Hakjune
, p. 112 - 114 (2007/10/03)
Several amides were obtained by an efficient method from the corresponding alkyl aryl ketimines in high yields. Ketimines are readily prepared from the corresponding ketones. This procedure involves the oxidation of alkyl aryl ketimines with MCPBA with BF3·OEt2. In this reaction, only aryl group of alkyl aryl ketimines was migrated to the electron deficient nitrogen atom.
Triphenylphosphine/germanium(IV) chloride combination: A new agent for the reduction of α-bromo carboxylic acid derivatives
Kagoshima, Hirotaka,Hashimoto, Yukihiko,Oguro, Dai,Kutsuna, Takaaki,Saigo, Kazuhiko
, p. 1203 - 1206 (2007/10/03)
The Ph3P/GeCl4 combination was found to be effective for the reduction of various α-bromo carboxylic acid derivatives. When a-bromo carboxylic acid derivatives were treated with Ph3P/GeCl4, the corresponding dehalogenated products were obtained in good to excellent yields. Moreover, selected carboxylic acid derivatives were dehalogenated even when a catalytic amount (0.2 equiv) of GeCl4 was employed in the presence of water (1.0 equiv). The present reduction was also applied to the selective half-reduction of an α,α-dibromo-β-lactam.
Rearrangement Reactions of Oxaziridines to Nitrones. X-Ray Crystal and Molecular Structure of N-t-Butyl-α(o-hydroxyphenyl)nitrone
Christensen, Dorthe,Jorgensen, Karl Anker,Hazell, Rita G.
, p. 2391 - 2397 (2007/10/02)
Substituted N-benzylidene-t-butylamines are oxidized with m-chloroperoxybenzoic acid to oxaziridines which can rearrange to the corresponding nitrones when electron-donating groups are present in the phenyl ring.The oxaziridine-to-nitrone rearrangement, which has been considered as a 'pseudo-abnormal' reaction, can also be catalysed by Lewis acids.It has been found that the rearrangement of 2-t-butyl-3-(o-hydroxyphenyl)oxaziridine to the corresponding nitrone is of first order.The rearrangement has been investigated for different substituents in the phenyl ring, andin the case of 2-t-butyl-3-phenyloxaziridine substituted in the ortho position with electron-donating groups it has been found that the presence of protons of a Lewis acid is necessary.An X-ray structure of α-(o-hydroxyphenyl)-N-t-butylnitrone shows strong hydrogen bonding between the nitrone oxygen and the hydrogen in the hydroxy group.The oxaziridine-to-nitrone rearrangement is also analysed from a theoretical point of view using ab initio calculations.A Mulliken-population analysis of the C-O and N-O bonds in the oxaziridine ring for para-substitued 2-t-butyl-3-phenyloxaziridines shows a reduction of the C-O bond population when an electron-donating group is present in the para position of the phenyl ring compared with an electron-withdrawing group; the N-O bond populations show the reverse picture.A state-correlation diagram for the oxaziridine-to-nitrone rearrangement is also presented and the experimental and theoretical results support each other.
