- Preparation of alkylated compounds using the trialkylphosphate
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[Problem] trialkylphosphate strong base used reaction agent, a carboxylic acid, a ketone, an aldehyde, amine, amide, thiol, ester or Grignard reagent to a variety of substrates, and/or high efficiency to generate a highly stereoselective alkylation reaction, the alkylated compounds capable of producing new means. [Solution] was used as the alkylating agent in the alkylation of compound trialkylphosphate, strongly basic reaction production use. [Drawing] no
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Paragraph 0184-0185; 0200
(2021/11/02)
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- Regio- And Stereoselective (S N2) N -, O -, C - And S -Alkylation Using Trialkyl Phosphates
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Bimolecular nucleophilic substitution (S N 2) is one of the most well-known fundamental reactions in organic chemistry to generate new molecules from two molecules. In principle, a nucleophile attacks from the back side of an alkylating agent having a suitable leaving group, most commonly a halide. However, alkyl halides are expensive, very harmful, toxic and not so stable, which makes them problematic for laboratory use. In contrast, trialkyl phosphates are inexpensive, readily accessible and stable at room temperature, under air, and are easy to handle, but rarely used as alkylating agents in organic synthesis. Here, we describe a mild, straightforward and powerful method for nucleophilic alkylation of various N -, O -, C - and S -nucleophiles using readily available trialkyl phosphates. The reaction proceeds smoothly in excellent yield, and quantitative yield in many cases, and covers a wide range of substrates. Further, the rare stereoselective transfer of secondary alkyl groups has been achieved with inversion of configuration of chiral centers (up to 98% ee).
- Banerjee, Amit,Hattori, Tomohiro,Yamamoto, Hisashi
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- Nickel-Catalyzed Oxidative Transamidation of Tertiary Aromatic Amines with N -Acylsaccharins
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The use of tertiary amines as surrogates for secondary amines has prominent advantages in terms of stabilization and ease of handling. A Ni-catalyzed transamidation of N -acylsaccharins with tertiary aromatic amines is reported. By using tert -butyl hydroperoxide as the terminal oxidant, this reaction permits selective cleavage of the C(sp 3)-N bonds of unsymmetrical tertiary aromatic amines depending on the sizes of the alkyl substituents.
- Liu, Shengzhang,Yang, Lingyun,Tao, Jiasi,Yu, Weijie,Wang, Tao,Fu, Junkai
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supporting information
p. 1642 - 1646
(2021/06/21)
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- Ultrafast amidation of esters using lithium amides under aerobic ambient temperature conditions in sustainable solvents
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Lithium amides constitute one of the most commonly used classes of reagents in synthetic chemistry. However, despite having many applications, their use is handicapped by the requirement of low temperatures, in order to control their reactivity, as well as the need for dry organic solvents and protective inert atmosphere protocols to prevent their fast decomposition. Advancing the development of air- and moisture-compatible polar organometallic chemistry, the chemoselective and ultrafast amidation of esters mediated by lithium amides is reported. Establishing a novel sustainable access to carboxamides, this has been accomplished via direct C-O bond cleavage of a range of esters using glycerol or 2-MeTHF as a solvent, in air. High yields and good selectivity are observed while operating at ambient temperature, without the need for transition-metal mediation, and the protocol extends to transamidation processes. Pre-coordination of the organic substrate to the reactive lithium amide as a key step in the amidation processes has been assessed, enabling the structural elucidation of the coordination adduct [{Li(NPh2)(OCPh(NMe2))}2] (8) when toluene is employed as a solvent. No evidence for formation of a complex of this type has been found when using donor THF as a solvent. Structural and spectroscopic insights into the constitution of selected lithium amides in 2-MeTHF are provided that support the involvement of small kinetically activated aggregates that can react rapidly with the organic substrates, favouring the C-O bond cleavage/C-N bond formation processes over competing hydrolysis/degradation of the lithium amides by moisture or air.
- Bole, Leonie J.,Fairley, Michael,García-Alvarez, Joaquín,Hevia, Eva,Kennedy, Alan R.,Main, Laura,Mulks, Florian F.,O'Hara, Charles T.
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p. 6500 - 6509
(2020/07/15)
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- Facile amidation of esters with aromatic amines promoted by lanthanide tris (amide) complexes
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The development of catalysts capable of catalyzing amidation of esters with amines to construct amides under mild conditions is of great importance. Compared to aliphatic amines, the direct catalytic amidation of esters with less nucleophilic aromatic amines is rather difficult. Employing simple lanthanide tris (amide) complexes Ln[N (SiMe3)2]3(μ-Cl)Li (THF)3 as the catalysts, it was found a broad range of aromatic amines and esters were efficiently converted into various amides in good yields under mild conditions. A plausible mechanism for this transformation was experimentally supported as starting from an amide exchange reaction between the lanthanide tris (amide) complex and the substrate amine.
- Li, Zhao,Guo, Chenjun,Chen, Jue,Yao, Yingming,Luo, Yunjie
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- Copper-Catalyzed Radical N-Demethylation of Amides Using N-Fluorobenzenesulfonimide as an Oxidant
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An unprecedented N-demethylation of N-methyl amides has been developed by use of N-fluorobenzenesulfonimide as an oxidant with the aid of a copper catalyst. The conversion of amides to carbinolamines involves successive single-electron transfer, hydrogen-atom transfer, and hydrolysis, and is accompanied by formation of N-(phenylsulfonyl)benzenesulfonamide. Carbinolamines spontaneously decompose to N-demethylated amides and formaldehyde, because of their inherent instability.
- Yi, Xuewen,Yi, Xuewen,Lei, Siyu,Liu, Wangsheng,Che, Fengrui,Yu, Chunzheng,Liu, Xuesong,Wang, Zonghua,Zhou, Xin,Zhang, Yuexia
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supporting information
p. 4583 - 4587
(2020/05/05)
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- HMF and furfural: Promising platform molecules in rhodium-catalyzed carbonylation reactions for the synthesis of furfuryl esters and tertiary amides
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A biomass involved rhodium-catalyzed carbonylative synthesis of furfuryl esters and tertiary amides has been developed. 5-Hydroxymethylfurfural (HMF) was used as both substrate and CO surrogate for the first time in a carbonylation reaction, and both alkyl and aryl iodides were tolerated well to afford the desired furfuryl esters in moderate to good yields. In addition, furfural was also utilized as a CO source for the synthesis of tertiary amides. A variety of tertiary amides were obtained in moderate to excellent yields with good functional groups compatibility. Notably, tertiary amines were used as the amine source through a C[sbnd]N bond cleavage pathway in the absence of additional oxidant.
- Qi, Xinxin,Zhou, Rong,Ai, Han-Jun,Wu, Xiao-Feng
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p. 215 - 221
(2019/11/25)
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- Enantioselective Desymmetrization of cis-3,5- O-Arylidenecyclohexanones Catalyzed by Cinchona-Derived Quaternary Ammonium Salts
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An enantioselective protocol for the desymmetrization of cis-3,5-O-arylidenecyclohexanones has been developed that proceeded under the catalysis of readily available and inexpensive Cinchona-derived quaternary ammonium salts. The synthetic relevance of the methodology was exemplified by the synthesis of a key intermediate that could be used in the preparation of the active pharmaceutical ingredient, paricalcitol (Zemplar).
- Cortigiani, Mauro,Gillick Healy, Malachi,Mereu, Andrea,Adamo, Mauro F. A.
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p. 4112 - 4119
(2019/04/30)
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- Straightforward α-Amino Nitrile Synthesis Through Mo(CO)6-Catalyzed Reductive Functionalization of Carboxamides
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The selective reduction of amides into an intermediate hemiaminal catalyzed by Mo(CO)6 together with the inexpensive and easy to handle TMDS (1,1,3,3-tetramethyldisiloxane) as reducing agent, followed by subsequent trapping of the hemiaminal with a cyanide source, allows for the straightforward synthesis of α-amino nitriles. The methodology presented here, displays high levels of chemoselectivity allowing for the reduction of amides in the presence of functional groups such as ketones, imines, aldehydes, and acids, which affords a simple route for the synthesis of α-amino nitriles with a broad scope of functionalities in high yields. Furthermore, the applicability of this methodology is demonstrated by scale up experiments and by derivatization of the target compounds into synthetically interesting products. The selective cyanation is successfully applied in late stage functionalizations of amide containing drugs and prolinol derivatives.
- Trillo, Paz,Slagbrand, Tove,Adolfsson, Hans
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supporting information
p. 12347 - 12351
(2018/09/10)
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- NBu4NI-catalyzed oxidative amidation of aldehydes with tertiary amines
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An efficient oxidative coupling protocol for amide formation has been developed. Various tertiary amines and aromatic aldehydes were oxidized to their corresponding tertiary amides in moderate to good yields in the presence of a simple nBu4NI-catalyst.
- Wang, Shan,Wang, Jian,Guo, Rui,Wang, Gao,Chen, Shan-Yong,Yu, Xiao-Qi
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supporting information
p. 6233 - 6236
(2013/10/22)
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- Radical OfC transposition: A metal-free process for conversion of phenols into benzoates and benzamides
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We report a metal-free procedure for transformation of phenols into esters and amides of benzoic acids via a new radical cascade. Diaryl thiocarbonates and thiocarbamates, available in a single high-yielding step from phenols, selectively add silyl radicals at the sulfur atom of the CdS moiety. This addition step, analogous to the first step of the Barton-McCombie reaction, produces a carbon radical which undergoes 1,2 OfC transposition through an O-neophyl rearrangement. The usually unfavorable equilibrium in the reversible rearrangement step is shifted forward via a highly exothermic C-S bond scission in the O-centered radical, which furnishes the final benzoic ester or benzamide product. The metal-free preparation of benzoic acid derivatives from phenols provides a potentially useful alternative to metal-catalyzed carbonylation of aryl triflates.
- Baroudi, Abdulkader,Alicea, Jeremiah,Flack, Phillip,Kirincich, Jason,Alabugin, Igor V.
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scheme or table
p. 1521 - 1537
(2011/06/11)
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- DIRECT CONVERSION OF PHENOLS INTO AMIDES AND ESTERS OF BENZOIC ACID
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A method is provided for the preparation of an aromatic carboxylic acid aryl ester or an N-aryl aromatic carboxamide. The method comprises contacting an O,O-diaryl thiocarbonate or an O-aryl-N-aryl thiocarbamate with a reactant that regioselectively reacts with sulfur, which contact causes an O-neophyl rearrangement, thereby forming either the aromatic carboxylic acid aryl ester or the N-aryl aromatic carboxamide, respectively.
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Page/Page column 15-16; 21
(2011/10/12)
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- Metal-free transformation of phenols into substituted benzamides: A highly selective radical 1,2-O→C transposition in O-aryl-N-phenylthiocarbamates
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Radical merry-go-round: A highly efficient metal-free transformation of phenols into benzamides is designed through one-step conversion of phenols to aryl thiocarbamates and a subsequent radical addition/rearrangement/ fragmentation cascade. Computational analysis fully rationalizes the experimentally observed selectivity. Despite the possible competition from N-C fragmentation and N-neophyl rearrangement, the transformation exclusively follows the most kinetically and thermodynamically favored O-neophyl rearrangement path.
- Baroudi, Abdulkader,Flack, Phillip,Alabugin, Igor V.
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supporting information; experimental part
p. 12316 - 12320
(2010/12/29)
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- Synthesis, structure, and acylating properties of 1-aroyloxy-4,5-dimethyl- 1,2,3-triazoles
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Lead tetra-acetate oxidation of α-hydroxyimino aroylhydrazones of biacetyl (1) gives 1-aroyloxy-4,5-dimethyl-1,2,3-triazoles (2), the structures of which were confirmed by X-ray analysis. A mechanism for this reaction is discussed. The products (2) are effective aroylating agents for the amino function under mild conditions.
- Theocharis,Maroulis,Hadjiantoniou-Maroulis,Alexandrou
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p. 619 - 621
(2007/10/02)
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