92520-13-3Relevant academic research and scientific papers
Biocatalytic, Intermolecular C?H Bond Functionalization for the Synthesis of Enantioenriched Amides
Arnold, Frances H.,Athavale, Soumitra V.,Gao, Shilong,Hirschi, Jennifer S.,Liu, Zhen,Mallojjala, Sharath Chandra
supporting information, p. 24864 - 24869 (2021/10/15)
Directed evolution of heme proteins has opened access to new-to-nature enzymatic activity that can be harnessed to tackle synthetic challenges. Among these, reactions resulting from active site iron-nitrenoid intermediates present a powerful strategy to forge C?N bonds with high site- and stereoselectivity. Here we report a biocatalytic, intermolecular benzylic C?H amidation reaction operating at mild and scalable conditions. With hydroxamate esters as nitrene precursors, feedstock aromatic compounds can be converted to chiral amides with excellent enantioselectivity (up to >99 % ee) and high yields (up to 87 %). Kinetic and computational analysis of the enzymatic reaction reveals rate-determining nitrenoid formation followed by stepwise hydrogen atom transfer-mediated C?H functionalization.
C-H Amination via Electrophotocatalytic Ritter-Type Reaction
Lambert, Tristan H.,Shen, Tao
supporting information, p. 8597 - 8602 (2021/06/28)
A method for C-H bond amination via an electrophotocatalytic Ritter-Type reaction is described. The reaction is catalyzed by a trisaminocyclopropenium (TAC) ion in an electrochemical cell under irradiation. These conditions convert benzylic C-H bonds to acetamides without the use of a stoichiometric chemical oxidant. A range of functionality is shown to be compatible with this transformation, and several complex substrates are demonstrated.
Chemoselective formation of C–N bond in wet acetonitrile using amberlyst-15(H) as a recyclable catalyst
Nandy, Sneha,Das, Asit Kumar,Bhar, Sanjay
supporting information, p. 3326 - 3336 (2020/08/13)
An economically efficient and environmentally benign protocol for the chemoselective one-pot synthesis of diversely N-substituted amides has been developed in good yield through the reaction of benzylic secondary alcohols as well as aliphatic tertiary alcohols and alkyl/aryl nitriles. Commercially available Amberlyst-15(H) has been utilized at 80 °C as an air-stable and reusable heterogeneous inexpensive solid acid catalyst without any anhydrous and inert environment. The attractive features of the present synthetic protocol are mild reaction conditions, short reaction time, excellent chemoselectivity, high atom economy and tolerance of various sensitive moieties.
Preparation, characterization and catalytic activity of palladium catalyst supported on MgCO3 for dynamic kinetic resolution of amines
Ferreira, Marina M. M.,Cabreira, Camila R.,Chaves, Pedro H. K.,Labussiére, Gabriela M.,Zimpeck, Renata C.,De Lima, Sania M.,De Siqueira, Fernanda A.
, p. 2144 - 2149 (2018/09/29)
Pd nanoparticle catalyst loading 4.7 wt.percent was prepared by the deposition-precipitation method and characterized by X-ray diffraction and transmission electron microscopy (TEM). The crystallite size estimated from the integral width of the highest intensity line using the Scherrer equation was 2.3 nm. Images obtained from TEM showed an equal distribution of the particles size between 0-2 and 2-4 nm, and also a good dispersion of the nanoparticles on the catalyst support. The catalytic activity of this nanocatalyst was studied for racemization reactions of (S)-(-)-1-phenylethylamine. After that, the catalyst was used in the chemoenzymatic dynamic kinetic resolution (DKR) of some primary amines. Expressive yields and optical purities were obtained.
A Single Lipase-Catalysed One-Pot Protocol Combining Aminolysis Resolution and Aza-Michael Addition: An Easy and Efficient Way to Synthesise β-Amino Acid Esters
Xu, Fan,Wu, Qiongsi,Chen, Xiaoyang,Lin, Xianfu,Wu, Qi
, p. 5393 - 5401 (2015/08/24)
A novel one-pot protocol combining aza-Michael addition and aminolysis resolution was developed to obtain chiral β-amino acid esters with lipase B from Candida antarctica (CAL-B) as the only catalyst. This method is conducted under mild reaction conditions and is very easy to handle. After a series of detailed optimization studies, ten racemic aromatic or aliphatic amines were subjected to this one-pot procedure, and twelve chiral β-amino acid esters and ten chiral amides were successfully synthesised with excellent ee values in theoretical yields. Scaled-up procedures also worked without apparent reduction in reaction rate or enantioselectivity, which makes this method suitable for large-scale production of chiral β-amino acid esters. A one-pot protocol for simultaneous synthesis of chiral β-amino acid esters and amides was developed by combining single lipase B from Candida antarctica (CAL-B) catalysed aza-Michael addition and aminolysis resolution. This method requires mild reaction conditions and is very easy to handle. Chiral β-amino acid esters and chiral amides were obtained with excellent ee values and in theoretical yields.
One-pot stibine modified Co2(CO)8 catalyzed reductive N-alkylation of primary amides with carbonyl compounds
Rubio-Pérez, Laura,Sharma, Pankaj,Pérez-Flores, F. Javier,Velasco, Luis,Arias, J. Luis.,Cabrera, Armando
experimental part, p. 2342 - 2348 (2012/04/10)
A one-pot stibine modified Co2(CO)8 homogeneous catalytic reductive N-alkylation of primary amides using aldehydes/ketones as alkylating agents, is reported. Good to excellent yields of a wide range of secondary amides are obtained (up to 97%) under relative mild conditions.
Dynamic path bifurcation in the Beckmann reaction: Support from kinetic analyses
Yamamoto, Yutaro,Hasegawa, Hiroto,Yamataka, Hiroshi
experimental part, p. 4652 - 4660 (2011/07/29)
The reactions of oximes to amides, known as the Beckmann rearrangement, may undergo fragmentation to form carbocations + nitriles when the migrating groups have reasonable stability as cations. The reactions of oxime sulfonates of 1-substituted-phenyl-2-propanone derivatives (7-X) and related substrates (8-X, 9a-X) in aqueous CH3CN gave both rearrangement products (amides) and fragmentation products (alcohols), the ratio of which depends on the system; the reactions of 7-X gave amides predominantly, whereas 9a-X yielded alcohols as the major product. The logk-logk plots between the systems gave excellent linear correlations with slopes of near unity. The results support the occurrence of path bifurcation after the rate-determining TS of the Beckmann rearrangement/fragmentation reaction, which has previously been proposed on the basis of molecular dynamics simulations. It was concluded that path-bifurcation phenomenon could be more common than thought and that a reactivity-selectivity argument based on the traditional TS theory may not always be applicable even to a well-known textbook organic reaction.
HBF4·OEt2 as a mild and versatile reagent for the Ritter amidation of olefins: A facile synthesis of secondary amides
Subba Reddy,Sivasankar Reddy,Madan, Ch.,Yadav
experimental part, p. 4827 - 4829 (2010/10/02)
A variety of alkenes undergo smooth amidation with nitriles in the presence of HBF4·OEt2 at room temperature under mild conditions to afford the corresponding secondary amides in good to excellent yields. This is a highly efficient method for the preparation of α-aryl ethyl amides especially from vinyl arenes without any side reactions such as olefin polymerization. The use of readily available and easy to handle reagent HBF4·OEt2 makes this method simple, convenient, and practical.
Electron-donating and rigid p-stereogenic bisphospholane ligands for highly enantioselective rhodium-catalyzed asymmetric hydrogenations
Zhang, Xiaowei,Huang, Kexuan,Hou, Guohua,Cao, Bonan,Zhang, Xumu
supporting information; experimental part, p. 6421 - 6424 (2010/12/19)
More electron donating, more rigid: A new highly electron-donating P-stereogenic bisphospholane ligand (ZhangPhos) was synthesized in a practical and highly enantioselective manner from a commercially available chiral source. Better or comparable enantioselectivities and reactivities than TangPhos were achieved in rhodium-catalyzed hydrogenation of various functionalized olefins (see scheme; nbd=3,5-norbornadiene). Copyright
Highly enantioselective hydrogenation of enamides catalyzed by chiral phosphoric acids
Li, Guilong,Antilla, Jon C.
supporting information; experimental part, p. 1075 - 1078 (2009/07/25)
A highly enantioselective hydrogenation of enamides catalyzed by a dual chiral-achiral acid system was developed. By employing a substoichiometric amount of a chiral phosphoric acid and acetic acid, catalyst loadings as low as 1 mol % of the chiral cataly
