18871-71-1Relevant academic research and scientific papers
"Wolf and lamb" reactions: Equilibrium and kinetic effects in multipolymer systems
Cohen,Kraus,Patchornik
, p. 7620 - 7629 (1981)
Two reagents reacting avidly with each other in solution are rendered mutually inactive by attaching each to a separate batch of insoluble polymer. Two-stage reactions in which a soluble reagent reacts first with one polymeric reagent and the product with the second polymeric reagent afford advantages over analogous reactions in solution. In acylation reactions of carbon acids, the simultaneous use of a polymeric strong base and a polymeric acylating reagent proved to be superior to the use of soluble reagents, both for bringing about quantitative acylations and for coping with undesirable side reactions. New polymeric strong bases were prepared: polymeric trityllithium, para-substituted trityllithium polymers, and polymeric lithium diisopropylamide. Active esters of polymeric o-nitrophenol and N-1-hydroxybenzotriazole were used as acylation reagents. The scope and limitation of these reactions and their application to general multiphase systems are discussed.
Nickel-Catalyzed Claisen Condensation Reaction between Two Different Amides
Chen, Jiajia,Xu, Man,Yu, Subeen,Xia, Yuanzhi,Lee, Sunwoo
supporting information, p. 2287 - 2292 (2020/03/16)
A nickel-catalyzed Claisen condensation reaction between two amides, where one possesses an α-proton, for the synthesis of β-ketoamides was developed. Ni(glyme)Cl2 and terpyridine serve as the active catalysts in the presence of Mn and LiCl. N,N-Methylphenyl and N,N-diphenyl benzamide derivatives react with cyclic and noncyclic amides to give their corresponding β-ketoamides in moderate to good yields. In addition, a DFT calculation suggests that reductive elimination is the rate-determining step.
Chiral Vanadyl(V) Complexes Enable Efficient Asymmetric Reduction of β-Ketoamides: Application toward (S)-Duloxetine
Chen, Chien-Tien,Maity, Nabin Ch.,Agarwal, Rachit,Lai, Chien-Fu,Liao, Yiya,Yu, Wei-Ru
supporting information, p. 6408 - 6419 (2020/07/14)
High-valent chiral oxidovanadium(V) complexes derived from 3,5-substituted-N-salicylidene-l-tert-leucine were used as catalysts in asymmetric reduction of N-benzyl-β-ketoamides. Among six different solvents, three different alcohol additives, and two different boranes examined, the use of pinacolborane in tetrahydrofuran (THF) with a t-BuOH additive led to the best results at -20 °C. The corresponding β-hydroxyamides can be furnished with yields up to 92percent and an enantiomeric excess (ee) up to 99percent. We have successfully extended this catalytic protocol for the synthesis of an (S)-duloxetine precursor.
Selective cleaving the N–P bond of difluoromethylene phosphabetaines for effective synthesis of β-ketoamides
Liu, Yingle,Yang, Tao,Dong, Yuting,Cai, Junjie,Luo, Gen,Tong, Xia,Jiang, Yan,Yang, Yi,Xu, Xiu-Hua
supporting information, p. 1934 - 1937 (2019/06/25)
An unprecedent transition-metal-free protocol for the synthesis of β-ketoamides from β-ketoesters is described. This method involves selective cleaving N–P bond of an unusual aminating reagent, [tris(dimethylamino)phosphonio]difluoroacetate (ADFA), which
SO2F2-Mediated Oxidative Dehydrogenation and Dehydration of Alcohols to Alkynes
Zha, Gao-Feng,Fang, Wan-Yin,Li, You-Gui,Leng, Jing,Chen, Xing,Qin, Hua-Li
, p. 17666 - 17673 (2019/01/04)
Direct synthesis of alkynes from inexpensive, abundant alcohols was achieved in high yields (greater than 40 examples, up to 95% yield) through a SO2F2-promoted dehydration and dehydrogenation process. This straightforward transformation of sp3-sp3 (C-C) bonds to sp-sp (C=C) bonds requires only inexpensive and readily available reagents (no transition metals) under mild conditions. The crude alkynes are sufficiently free of impurities to permit direct use in further transformations, as illustrated by regioselective Huisgen alkyne-azide cycloaddition reactions with PhN3 to give 1,4-substituted 1,2,3-traiazoles (16 examples, up to 92% yield) and Sonogashira couplings (10 examples, up to 77% yield).
Method for applying discodermia phosphonium inner salt serving as novel ammonolysis reagent to synthesizing beta-keto-amide
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Paragraph 0033; 0034; 0035; 0036; 0037, (2017/04/26)
The invention discloses a method for applying discodermia phosphonium inner salt serving as a novel ammonolysis reagent to synthesizing beta-keto-amide. Under inert gas protection, in a polar solvent, beta-keto ester and discodermia phosphonium inner salt are adopted as raw materials, full stirring is carried out at certain temperature, and after the reaction is completed, beta-keto-amide is obtained through separation and purification. The method is mild in reaction condition, high in operability, low in cost, high in safety, environmentally friendly, high in reaction conversion rate and yield and short in technological process and has the advantage of being suitable for industrial production, the reaction scale is easy to expand, and product separation is easy.
Creation through immobilization: A new family of high performance heterogeneous bifunctional iminophosphorane (BIMP) superbase organocatalysts
Goldys, Anna M.,Nez, Marta G.,Dixon, Darren J.
supporting information, p. 6294 - 6297 (2015/02/05)
An immobilized chiral bifunctional iminophosphorane superbase organocatalyst has been developed and applied in a range of challenging enantioselective reactions. A unique feature of this novel catalytic system is that the final step creation of the iminophosphorane occurs at the point of immobilization. The utility of the immobilized catalyst system was demonstrated in the nitro-Mannich reaction of ketimines as well as the conjugate addition of high pKa 1,3-dicarbonyl pro-nucleophiles to nitrostyrene. Catalyst recycling was also demonstrated.
Direct synthesis of polysubstituted 2-aminothiophenes by Cu(ii)-catalyzed addition/oxidative cyclization of alkynoates with thioamides
Ge, Li-Shi,Wang, Zheng-Lin,An, Xing-Lan,Luo, Xiaoyan,Deng, Wei-Ping
supporting information, p. 8473 - 8479 (2014/12/10)
A facile and direct synthetic method was developed for the construction of structurally important 2-aminothiophenes in moderate to excellent yields (up to 91%), via Cu(ii)-catalyzed addition/oxidative cyclization of readily available thioamides with alkynoates under an air atmosphere. This journal is
Organocatalytic enantio- and diastereoselective conjugate addition to nitroolefins: When ketoamides surpass ketoesters
Du, Haiying,Rodriguez, Jean,Bugaut, Xavier,Constantieux, Thierry
supporting information, p. 8458 - 8466 (2014/07/08)
Our findings on the bifunctional squaramide-catalyzed enantioselective conjugate addition of ketoamides to nitroolefins are disclosed. It appears that simple acyclic methylene ketoamides, unlike the extensively studied ketoesters, afford the products in excellent diastereoselectivities, and maintain high yields and enantioselectivities. Moreover, competition and kinetic studies were conducted to rationalize the observed reactivity and selectivity. The high level of diastereocontrol, along with the amenability of the amide group to postfunctionalization, dramatically increase the synthetic usefulness of the transformation.
Orthoamides and iminium salts, LXXIII1: Contributions to the cleavage of carboxylic acid orthoamides - A new access to N,N,N',N'-tetraalkyl- carboxamidinium salts
Kantlehner, Willi,Lehmann, Hans Joerg,Stieglitz, Ruediger
, p. 442 - 456 (2013/09/24)
(Formula Presented) Orthoamides 7b-e of alkyne carboxylic acids are transformed by benzoyl chloride to give the corresponding amidinium chlorides 13b-f, which were isolated as the tetraphenylborates 14. The reaction of the orthoamide derivative of phenylp
