17598-10-6Relevant articles and documents
Defunctionalization of sp3 C–Heteroatom and sp3 C–C Bonds Enabled by Photoexcited Triplet Ketone Catalysts
An, Juzeng,Gu, Yiting,Martin, Ruben,Wakeling, Matthew,Yin, Hongfei
, p. 1031 - 1036 (2022/01/19)
A general strategy for enabling a light-induced defunctionalization of sp3 C–heteroatom and sp3 C–C bonds with triplet ketone catalysts and bipyridine additives is disclosed. This protocol is characterized by its broad scope without recourse to transition metal catalysts or stoichiometric exogeneous reductants, thus offering a complementary technique for activating σ sp3 C–C(heteroatom) bonds. Preliminary mechanistic studies suggest that the presence of 2,2′-bipyridines improves the lifetime of ketyl radical intermediates.
Near-Ambient-Temperature Dehydrogenative Synthesis of the Amide Bond: Mechanistic Insight and Applications
Kar, Sayan,Xie, Yinjun,Zhou, Quan Quan,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
, p. 7383 - 7393 (2021/06/30)
The current existing methods for the amide bond synthesis via acceptorless dehydrogenative coupling of amines and alcohols all require high reaction temperatures for effective catalysis, typically involving reflux in toluene, limiting their potential practical applications. Herein, we report a system for this reaction that proceeds under mild conditions (reflux in diethyl ether, boiling point 34.6 °C) using ruthenium PNNH complexes. The low-temperature activity stems from the ability of Ru-PNNH complexes to activate alcohol and hemiaminals at near-ambient temperatures through the assistance of the terminal N-H proton. Mechanistic studies reveal the presence of an unexpected aldehyde-bound ruthenium species during the reaction, which is also the catalytic resting state. We further utilize the low-temperature activity to synthesize several simple amide bond-containing commercially available pharmaceutical drugs from the corresponding amines and alcohols via the dehydrogenative coupling method.
Iridium-PPh3 Catalysts for Conversion of Amides to Enamines
Une, Yuta,Tahara, Atsushi,Miyamoto, Yasumitsu,Sunada, Yusuke,Nagashima, Hideo
supporting information, p. 852 - 862 (2019/03/04)
Studies on the deactivation mechanism of the reaction of N,N-dialkylamides with TMDS catalyzed by Vaska's complex, IrCl(CO)(PPh3)2 (1a), triggered the discovery of highly active Ir-PPh3 catalysts: Photochemically activated
Iron-Catalyzed Amide Formation from the Dehydrogenative Coupling of Alcohols and Secondary Amines
Lane, Elizabeth M.,Uttley, Katherine B.,Hazari, Nilay,Bernskoetter, Wesley
, p. 2020 - 2025 (2017/06/13)
The five-coordinate iron(II) hydride complex (iPrPNP)Fe(H)(CO) (iPrPNP = N[CH2CH2(PiPr2)]2) selectively catalyzes the dehydrogenative intermolecular coupling of alcohols and secondary amines to form tertiary amides. This is the most productive base-metal catalyst for dehydrogenative amidation reported to date, in some cases achieving up to 600 turnovers. The catalyst works well for sterically undemanding amines and alcohols or cyclic substrates and is particularly effective in the synthesis of formamides from methanol. However, the catalyst performance declines rapidly with the incorporation of large substituents on the amine or alcohol substrate. Variable-temperature NMR spectroscopic studies suggest that the catalyst resting state is an off-cycle iron(II) methoxide species, (iPrPN(H)P)Fe(H)(OCH3)(CO), resulting from addition of methanol across the Fe-N bond of (iPrPNP)Fe(H)(CO). This reversibly formed iron(II) methoxide complex is favored at mild temperatures but eliminates methanol upon heating.
CuCl/TBHP catalyzed synthesis of amides from aldehydes and amines in water
Lu, Shao-Yi,Badsara, Satpal Singh,Wu, Yi-Chun,Reddy, Daggula Mallikarjuna,Lee, Chin-Fa
supporting information, p. 633 - 636 (2016/01/26)
A CuCl/TBHP catalyzed amidation of aldehydes with amine under aqueous media is described. Both aliphatic and aromatic aldehydes coupled with a variety of amines under the reaction conditions employed.
Mild and direct conversion of esters to morpholine amides using diisobutyl(morpholino)aluminum: Application to efficient one-pot synthesis of ketones and aldehydes from esters
Jeon, Ah Ram,Kim, Min Eai,Park, Jae Kyo,Shin, Won Kyu,An, Duk Keun
, p. 4420 - 4424 (2014/06/10)
Morpholine amide intermediates, which are easily prepared by aminolysis of various esters with diisobutyl(morpholino)aluminum, react with organolithium and reducing agents (DIBALH or LDBMA) without isolation of the aminolysis intermediates to give ketones in 83-95% yields and aldehydes quantitatively.
Transamidation of amides with amines under solvent-free conditions using a CeO2 catalyst
Tamura, Masazumi,Tonomura, Takuya,Shimizu, Ken-Ichi,Satsuma, Atsushi
experimental part, p. 717 - 724 (2012/05/07)
Among various metal oxides, cerium oxide (CeO2) shows the highest catalytic activity for transamidation of picolinamide with n-octylamine. CeO2 acts as a reusable and effective heterogeneous catalyst for transamidation under solvent-free conditions. Transamidation of a variety of amides and amines produced the corresponding N-alkyl amides in high yields. This method provides the first example of a heterogeneous catalyst for transamidation using aliphatic amines as substrates. Characterization of acid-base properties and kinetic studies suggest that the cooperation of the weak Lewis acid sites and adjacent strong base sites play important roles in the transamidation reaction. The Royal Society of Chemistry 2012.
Recyclable hypervalent iodine(III) reagent iodosodilactone as an efficient coupling reagent for direct esterification, amidation, and peptide coupling
Tian, Jun,Gao, Wen-Chao,Zhou, Dong-Mei,Zhang, Chi
supporting information; experimental part, p. 3020 - 3023 (2012/08/07)
A hypervalent iodine(III) reagent plays a novel role as an efficient coupling reagent to promote the direct condensation between carboxylic acids and alcohols or amines to provide esters, macrocyclic lactones, amides, as well as peptides without racemization. The regeneration of iodosodilactone (1) can also be readily achieved. The intermediate acyloxyphosphonium ion C from the activation of a carboxylic acid is thought to be involved in the present esterification reaction.
Synthesis of amides from esters and amines with liberation of H2 under neutral conditions
Gnanaprakasam, Boopathy,Milstein, David
supporting information; experimental part, p. 1682 - 1685 (2011/04/22)
Efficient synthesis of amides directly from esters and amines is achieved under mild, neutral conditions with the liberation of molecular hydrogen. Both primary and secondary amines can be utilized. This unprecedented, general, environmentally benign reaction is homogeneously catalyzed under neutral conditions by a dearomatized ruthenium-pincer PNN complex and proceeds in toluene under an inert atmosphere with a high turnover number (up to 1000). PNP analogues do not catalyze this transformation, underlining the crucial importance of the amine arm of the pincer ligand. A mechanism is proposed involving metal-ligand cooperation via aromatization-dearomatization of the pyridine moiety and hemilability of the amine arm.
