16547-13-0Relevant academic research and scientific papers
Reverse Polarity Reductive Functionalization of Tertiary Amides via a Dual Iridium-Catalyzed Hydrosilylation and Single Electron Transfer Strategy
Dixon, Darren J.,Duarte, Fernanda,Gabriel, Pablo,Leitch, Jamie A.,Rogova, Tatiana,Zavitsanou, Stamatia
, p. 11438 - 11447 (2020)
A strategy for the mild generation of synthetically valuable α-amino radicals from robust tertiary amide building blocks has been developed. By combining Vaska's complex-catalyzed tertiary amide reductive activation and photochemical single electron reduction into a streamlined tandem process, metastable hemiaminal intermediates were successfully transformed into nucleophilic α-amino free radical species. This umpolung approach to such reactive intermediates was exemplified through coupling with an electrophilic dehydroalanine acceptor, resulting in the synthesis of an array of α-functionalized tertiary amine derivatives, previously inaccessible from the amide starting materials. The utility of the strategy was expanded to include secondary amide substrates, intramolecular variants, and late-stage functionalization of an active pharmaceutical ingredient. Density functional theory analyses were used to establish the reaction mechanism and elements of the chemical system that were responsible for the reaction's efficiency.
BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
Fan, Qing-Hua,Liu, Xintong,Luo, Zhenli,Pan, Yixiao,Xu, Lijin,Yang, Ji,Yao, Zhen,Zhang, Xin
supporting information, p. 5205 - 5211 (2021/07/29)
A versatile metal- and base-free direct reductive amination of aldehydes with amines using formic acid as a reductant under the catalysis of inexpensive BF3·Et2O has been developed. A wide range of primary and secondary amines and diversely substituted aldehydes are compatible with this transformation, allowing facile access to various secondary and tertiary amines in high yields with wide functional group tolerance. Moreover, the method is convenient for the late-stage functionalization of bioactive compounds and preparation of commercialized drug molecules and biologically relevant N-heterocycles. The procedure has the advantages of simple operation and workup and easy scale-up, and does not require dry conditions, an inert atmosphere or a water scavenger. Mechanistic studies reveal the involvement of imine activation by BF3and hydride transfer from formic acid.
Direct N-Alkylation/Fluoroalkylation of Amines Using Carboxylic Acids via Transition-Metal-Free Catalysis
Lu, Chunlei,Qiu, Zetian,Xuan, Maojie,Huang, Yan,Lou, Yongjia,Zhu, Yiling,Shen, Hao,Lin, Bo-Lin
supporting information, p. 4151 - 4158 (2020/08/21)
A scalable protocol of direct N-mono/di-alkyl/fluoroalkylation of primary/secondary amines has been constructed with various carboxylic acids as coupling agents under the catalysis of a simple air-tolerant inorganic salt, K3PO4. Advantageous features include 100 examples, 10 drugs and drug-like amines, fluorinated complex tertiary amines, gram-scale synthesis and isotope-labelling amine, thus demonstrating the potential applicability in industry of this methodology. The involvement of relatively less reactive silicon-hydride compared with the traditional reactive metal-hydride or boron-hydride species required to reduce the amide intermediates presumably contributes to the remarkable functional group compatibility. (Figure presented.).
Regioselective, Photocatalytic α-Functionalization of Amines
Leng, Lingying,Fu, Yue,Liu, Peng,Ready, Joseph M.
supporting information, p. 11972 - 11977 (2020/08/06)
Photocatalytic α-functionalization of amines provides a mild and atom-economical means to synthesize α-branched amines. Prior examples featured symmetrical or electronically biased substrates. Here we report a controllable α-functionalization of amines in which regioselectivity can be tuned with minor changes to the reaction conditions.
Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
supporting information, p. 3800 - 3806 (2019/07/12)
A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
supporting information, p. 2301 - 2308 (2019/01/30)
The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
Coupling of C(sp3)-H bonds with C(sp2)-O electrophiles: mild, general and selective
Gui, Yong-Yuan,Liao, Li-Li,Sun, Liang,Zhang, Zhen,Ye, Jian-Heng,Shen, Guo,Lu, Zhi-Peng,Zhou, Wen-Jun,Yu, Da-Gang
supporting information, p. 1192 - 1195 (2017/02/05)
Herein is reported the mild and general coupling of amine/ether C(sp3)-H bonds with various kinds of C(sp2)-O electrophiles with high selectivity and efficiency. Valuable allylic/benzylic amines are generated in moderate to excellent yields. The utility of this transformation is demonstrated by a broad substrate scope (>50 examples), good functional group tolerance and facile product modification.
General Reductive Amination of Aldehydes and Ketones with Amines and Nitroaromatics under H2 by Recyclable Iridium Catalysts
Sui, Dejun,Mao, Fei,Fan, Haipeng,Qi, Zhengliang,Huang, Jun
supporting information, p. 1371 - 137 (2017/10/05)
Heterogeneous iridium catalysts were prepared and applied for the reductive amination of aldehydes and ketones with nitroaromatics and amines using H2. The iridium catalysts were prepared by pyrolysis of ionic liquid 1-methyl-3-cyanomethylimidazoulium chloride ([MCNI]Cl) with iridium chloride (IrCl3) in activated carbons. Iridium particles were well dispersed and stable in the N-doped carbon materials from [MCNI]Cl with activated carbon. The Ir@NC(600-2h) catalyst was found to be highly active and selective for the reductive amination of aldehydes and ketones using H2 and a variety of nitrobenzenes and amines were selectively converted into the corresponding secondary and tertiary amines. The Ir@NC(600-2h) catalyst can be reusable several times without evident deactivation.
Heterogeneous cobalt catalysts for reductive amination with H2: General synthesis of secondary and tertiary amines
Mao, Fei,Sui, Dejun,Qi, Zhengliang,Fan, Haipeng,Chen, Rizhi,Huang, Jun
, p. 94068 - 94073 (2016/10/22)
Heterogeneous Co@NC catalysts were prepared, characterized and applied for the reductive amination of aldehydes and ketones with H2 gas. The Co catalyst Co@NC (800-2 h) was found to be active and selective for the reductive amination of aldehydes and ketones using H2 gas. Thus, general synthesis of secondary and tertiary amines was developed by the Co-catalyzed reductive amination with H2 gas, and various secondary and tertiary amines can be obtained in high yields. Moreover, a practical synthesis of N-substituted isoindolinones was also presented by a one step process with the Co@NC (800-2 h) catalyst. The Co@NC (800-2 h) catalyst is reusable at least five times without evident loss of activity.
