- New approach for induction of alkyl moiety to aliphatic amines by NaBH(OAc)3 with carboxylic acid
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We had found the novel N-alkylation method, which utilizes carboxylic acids as alkyl sources with sodium triacetoxyborohydride [NaBH(OAc)3]. Our methodology had been revealed to have some advantages over the reported similar procedures. Through
- Tamura, Satoru,Sugawara, Aoi,Sato, Erika,Sato, Fuka,Sato, Keigo,Kawano, Tomikazu
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supporting information
(2020/04/15)
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- A Supramolecular Strategy for Selective Catalytic Hydrogenation Independent of Remote Chain Length
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Performing selective transformations on complex substrates remains a challenge in synthetic chemistry. These difficulties often arise due to cross-reactivity, particularly in the presence of similar functional groups at multiple sites. Therefore, there is a premium on the ability to perform selective activation of these functional groups. We report here a supramolecular strategy where encapsulation of a hydrogenation catalyst enables selective olefin hydrogenation, even in the presence of multiple sites of unsaturation. While the reaction requires at least one sterically nondemanding alkene substituent, the rate of hydrogenation is not sensitive to the distance between the alkene and the functional group, including a carboxylate, on the other substituent. This observation indicates that only the double bond has to be encapsulated to effect hydrogenation. Going further, we demonstrate that this supramolecular strategy can overcome the inherent allylic alcohol selectivity of the free catalyst, achieving supramolecular catalyst-directed regioselectivity as opposed to directing-group selectivity.
- Bender, Trandon A.,Bergman, Robert G.,Raymond, Kenneth N.,Toste, F. Dean
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p. 11806 - 11810
(2019/08/22)
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- N-Acyl-N-(4-chlorophenyl)-4-nitrobenzenesulfonamides: Highly selective and efficient reagents for acylation of amines in water
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A variety of N-acyl-N-(4-chlorophenyl)-4-nitrobenzenesulfonamides (1a-e) were synthesized in one pot from 4-chloroaniline under solvent-free conditions and have been developed as chemoselective N-acylation reagents. Selective protection of primary amines in the presence of secondary amines, acylation of aliphatic amines in the presence of aryl amines, and monofunctionalization of primary-secondary diamines as well as selective N-acylation of amino alcohols using these reagents are described. All of the acylation reactions were carried out in water as a green solvent. High stability and easy preparation of these acylating reagents are other advantages of this method.
- Ebrahimi, Sara,Saiadi, Safoura,Dakhilpour, Simin,Mirsattari, Seyed Nezamoddin,Massah, Ahmad Reza
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- Iron-Catalyzed C-N Bond Formation via the Beckmann Rearrangement
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A simple, iron-based catalytic system allows for facile Beckmann rearrangement of various oximes. The mild conditions avoid the use of harsh or expensive acids, and the reactions do not require an inert atmosphere. Additionally, a range of amides can be accessed through this transformation.
- Jefferies, Latisha R.,Weber, Savannah R.,Cook, Silas P.
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supporting information
p. 331 - 334
(2015/02/19)
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- Chemo- and regioselective homogeneous rhodium-catalyzed hydroamidomethylation of terminal alkenes to N-alkylamides
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A rhodium/xantphos homogeneous catalyst system has been developed for direct chemo- and regioselective mono-N-alkylation of primary amides with 1-alkenes and syngas through catalytic hydroamidomethylation with 1-pentene and acetamide as model substrates. For appropriate catalyst performance, it appears to be essential that catalytic amounts of a strong acid promoter, such as p-toluenesulfonic acid (HOTs), as well as larger amounts of a weakly acidic protic promoter, particularly hexafluoroisopropyl alcohol (HORF) are applied. Apart from the product N-1-hexylacetamide, the isomeric unsaturated intermediates, hexanol and higher mass byproducts, as well as the corresponding isomeric branched products, can be formed. Under optimized conditions, almost full alkene conversion can be achieved with more than 80 % selectivity to the product N-1-hexylamide. Interestingly, in the presence of a relatively high concentration of HORF, the same catalyst system shows a remarkably high selectivity for the formation of hexanol from 1-pentene with syngas, thus presenting a unique example of a selective rhodium-catalyzed hydroformylation-hydrogenation tandem reaction under mild conditions. Time-dependent product formation during hydroamidomethylation batch experiments provides evidence for aldehyde and unsaturated intermediates; this clearly indicates the three-step hydroformylation/condensation/hydrogenation reaction sequence that takes place in hydroamidomethylation. One likely role of the weakly acidic protic promoter, HORF, in combination with the strong acid HOTs, is to establish a dual-functionality rhodium catalyst system comprised of a neutral rhodium(I) hydroformylation catalyst species and a cationic rhodium(III) complex capable of selectively reducing the imide and/or ene-amide intermediates that are in a dynamic, acid-catalyzed condensation equilibrium with the aldehyde and amide in a syngas environment. Taking control: A rhodium/xantphos homogeneous catalyst system has been developed for direct chemo- and regioselective mono-N-alkylation of primary amides with 1-alkenes and syngas through the new catalytic hydroamidomethylation reaction (see picture). Copyright
- Raoufmoghaddam, Saeed,Drent, Eite,Bouwman, Elisabeth
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p. 1759 - 1773
(2013/10/21)
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- Rhodium-catalyzed homogeneous reductive amidation of aldehydes
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The catalytic reductive amidation of an aldehyde (hexanal) with an amide (acetamide) is reported. Apart from the desired N-hexylacetamide, the two isomeric unsaturated intermediates as well as hexanol are produced together with higher mass products that arise from aldol condensation and diamide coupling of the aldehyde. Screening of different catalyst precursor salts, ligands and reaction conditions led to the finding that the catalytic system based on the (cyclooctadiene)rhodium chloride dimer, [Rh(cod)Cl]2, in combination with the ligand xantphos and an acid co-catalyst results in high selectivity for the desired product. Under optimized conditions nearly full conversion is reached with high selectivity to the desired N-alkylamide and with a very high N-alkylamide/alcohol ratio, while producing only small amounts of by-products. The scope of the reaction has been investigated using different amides as well as aldehydes; the results show the general applicability of this novel reaction, but with electron-withdrawing amides the selectivity to N-alkylamide is lower. NMR studies showed that the nucleophilic addition of acetamide to hexanal is acid catalyzed, forming N-(1-hydroxyhexyl)acetamide in equilibrium with both hexanal and the dehydrated unsaturated imides. A catalytic mechanism is proposed in which a strong acid such as HOTs acts as a co-catalyst by establishing a rapid chemical equilibrium between the aldehyde, acetamide and the intermediates. Furthermore, it is proposed that the presence of acid causes a change in catalytic species, enabling a cationic Rh/xantphos hydrogenation catalyst to selectively hydrogenate the intermediates to N-hexylacetamide in the presence of hexanal. Copyright
- Raoufmoghaddam, Saeed,Drent, Eite,Bouwman, Elisabeth
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supporting information
p. 717 - 733
(2013/04/23)
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- A simple, general, and highly chemoselective acetylation of alcohols using ethyl acetate as the acetyl donor catalyzed by a tetranuclear zinc cluster
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In the presence of a Zn-cluster catalyst, alcohols are efficiently converted to the corresponding acetate just by refluxing in EtOAc. The mild reaction conditions enabled the reactions of various functionalized alcohols to proceed in good to excellent yield. Moreover, even when a large excess of the acetyl donor is used, the hydroxyl groups are selectively acetylated in the presence of highly nucleophilic aliphatic amino groups, approaching chemoselectivity to that of enzymatic system. Georg Thieme Verlag Stuttgart.
- Iwasaki, Takanori,Maegawa, Yusuke,Hayashi, Yukiko,Ohshima, Takashi,Mashima, Kazushi
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experimental part
p. 1659 - 1663
(2009/12/04)
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- PRODUCTION METHOD FOR PRIMARY AMINE
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PROBLEM TO BE SOLVED: To provide a method for efficiently producing a primary amine. SOLUTION: By reacting n-hexyl acetate with ammonia in super-critical water as the reaction field, a reaction generating n-hexylamine, i.e. a reaction peculiar to super-critical water, is caused to occur. That is to say, a primary amine is generated by utilizing such a new chemical reaction that when ammonia is reacted with an acetate, a carbon atom adjacent to an ester bond is subjected to nucleophilic attack by ammonia, not by utilizing a normal-type reaction wherein the carbonyl carbon of an ester bond is subjected to the nucleophilic attack.
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Page/Page column 22-24; 48-50
(2008/06/13)
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- Synthesis of carboxamides by LDA-catalyzed Haller-Bauer and Cannizzaro reactions
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Equation presented. The first direct synthesis of N-alkylcarboxamides and N,N-dialkylcarboxamides by Haller-Bauer (HB) and Cannizzaro-type reactions has been realized. Lithium N,N-diisopropylamide (LDA) catalyst was successfully used in not only the HB reaction of benzylic ketones with lithium N-alkylamides to give the corresponding carboxamides and hydrocarbons but also in the Cannizzaro-type reaction of aldehydes with lithium N-alkylamides or lithium N,N-dialkylamides to give the corresponding carboxamides and alcohols.
- Ishihara, Kazuaki,Yano, Takayuki
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p. 1983 - 1986
(2007/10/03)
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