42331-17-9Relevant academic research and scientific papers
Aryl nitrenium ions from N-alkyl-N-arylamino-diazonium precursors: Synthesis and reactivity
Huh, Chan Woo,Aube, Jeffrey
, p. 699 - 706 (2014)
A means of generating an N-alkyl-N-arylaminodiazonium ion, which then loses nitrogen to form a reactive aryl nitrenium intermediate, is described. In this sequence, a set of triazenyl acetonitriles was synthesized by nucleophilic addition of a nitrile anion to an aryl azide followed by temperature-dependent alkylation at either of two nucleophilic triazenyl nitrogen atoms. An α,α-disubstituted acetonitrile and N-arylaminodiazonium moiety (or aryl nitrenium ion upon loss of N2) are embedded in the resulting 1,3,3-trisubsituted triazene, which undergoes liberation and recombination of these two components under acidic conditions to yield an α-arylated acetonitrile containing an all-carbon-quaternary center. We propose that the N-alkyl-N-arylaminodiazonium ion loses nitrogen to generate an aryl nitrenium species, which then reacts with an α,α-disubstituted acetonitrile either at the para- or meta-position of the aromatic ring to afford p-alkylaminoaryl acetonitrile derivatives or 3,3-substituted 1-methylindolin-2-imines, depending on the substrates and conditions.
Nickel-Catalyzed Aminofluoroalkylation of Alkenes: Access to Difluoroalkylated N-Containing Heterocyclic Compounds
Fu, Xiaoyi,Zhang, Tianyu,Wu, Jingjing,Sun, Yijie,Wu, Fanhong
supporting information, (2021/12/03)
A nickel-catalyzed aminofluoroalkylative cyclization of unactive alkenes with iododifluoromethyl ketones was developed to construct versatile difluoroalkylated Nitrogen-containing heterocycles including aziridines, pyrrolidines and piperidines in moderate to high yields. This method features a broad substrate scope and has been demonstrated on gram scale.
Enantiodivergent α-Amino C-H Fluoroalkylation Catalyzed by Engineered Cytochrome P450s
Zhang, Juner,Huang, Xiongyi,Zhang, Ruijie K.,Arnold, Frances H.
supporting information, p. 9798 - 9802 (2019/07/04)
The introduction of fluoroalkyl groups into organic compounds can significantly alter pharmacological characteristics. One enabling but underexplored approach for the installation of fluoroalkyl groups is selective C(sp3)-H functionalization due to the ubiquity of C-H bonds in organic molecules. We have engineered heme enzymes that can insert fluoroalkyl carbene intermediates into α-amino C(sp3)-H bonds and enable enantiodivergent synthesis of fluoroalkyl-containing molecules. Using directed evolution, we engineered cytochrome P450 enzymes to catalyze this abiological reaction under mild conditions with total turnovers (TTN) up to 4070 and enantiomeric excess (ee) up to 99%. The iron-heme catalyst is fully genetically encoded and configurable by directed evolution so that just a few mutations to the enzyme completely inverted product enantioselectivity. These catalysts provide a powerful method for synthesis of chiral organofluorine molecules that is currently not possible with small-molecule catalysts.
Direct ortho-Selective Amination of 2-Naphthol and Its Analogues with Hydrazines
Jia, Lei,Tang, Qiang,Luo, Meiming,Zeng, Xiaoming
, p. 5082 - 5091 (2018/05/15)
Described herein is a regioselective ortho-amination of 2-naphthol and its analogues with substituted hydrazines. It provides a direct methodology for the synthesis of N-arylaminated naphthol derivatives without the formation of related 1,1′-biaryl-2,2′-diamine or carbazole byproducts. Specifically, using N,N-disubstituted hydrazine precursors, N-unsubstituted ortho-aminated derivatives and related secondary amines can be formed in ethylene glycol in moderate to excellent yields. Variation of substrates to N,N′-diarylhydrazines and N-methyl-N,N′-diarylhydrazines led to N-aryl-1-amino-2-naphthol compounds. It is noted that biologically interesting indazole motifs can be facilely created by the reaction of N,N′-dialkylhydrazines with 2-naphthols. These ortho-amination reactions have the advantage of one-pot operation without the use of transition metal catalysts.
Aerobic intramolecular aminothiocyanation of unactivated alkenes promoted by in situ generated iodine thiocyanate
Feng, Yangyang,Hussain, Muhammad Ijaz,Zhang, Xiaohui,Shi, Jian,Hu, Wen,Xiong, Yan
supporting information, p. 2669 - 2676 (2018/05/04)
Aerobic intramolecular aminothiocyanation of unactivated alkenes has been developed by in situ generated iodine thiocyanate under open-flask conditions. This protocol provides a concise and efficient method for synthesizing SCN-containing pyrrolidine, piperidine and indoline derivatives with isolated yields of up to 87%. Furthermore, mixing iodine and sodium thiocyanate with oxygen afforded iodine thiocyanate (ISCN) and dithiocyanatoiodate [I(SCN)2]- which were testified by liquid chromatography mass spectrometry. A mechanistic investigation indicates that iodonium ion and sulfonium ion intermediates might be involved in this transformation.
Use of (cyclopentadienone)iron tricarbonyl complexes for c-n bond formation reactions between amines and alcohols
Brown, Thomas J.,Cumbes, Madeleine,Diorazio, Louis J.,Clarkson, Guy J.,Wills, Martin
, p. 10489 - 10503 (2018/05/31)
The application of a series of (cyclopentadienone)iron tricarbonyl complexes to "borrowing hydrogen" reactions between amines and alcohols was completed in order to assess their catalytic activity. The electronic variation of the aromatic groups flanking the C?O of the cyclopentadienone influenced the efficiency of the reactions; however, in other cases, the Kn?lker catalyst 1, containing trimethylsilyl groups flanking the cyclopentadienone ketone, gave the best results. In some cases, the change of the ratio of amine to alcohol improves the conversion significantly. The application of iron catalysts to the synthesis of a range of amines, including unsaturated amines, was investigated.
An Efficient Homogenized Ruthenium(II) Pincer Complex for N-Monoalkylation of Amines with Alcohols
Yang, Fa-Liu,Wang, Ying-Hui,Ni, Yong-Feng,Gao, Xiang,Song, Bing,Zhu, Xinju,Hao, Xin-Qi
, p. 3481 - 3486 (2017/07/04)
An ionic 2,6-bis(imidazo[1,2-α]pyridin-2-yl)pyridine-based N^N^N pincer ruthenium(II) complex exhibited high efficiency in the C–N bond formation between amines and alcohols by the “borrowing hydrogen” (BH) or “hydrogen autotransfer” (HA) concept. The synthetic protocol selectively generated monoalkylated amines without formation of tertiary amines during the reaction. The unique selectivity enabled the formation of symmetrically and asymmetrically substituted diamines. This methodology features several advantages including a low catalyst loading (as low as 0.5 mol-%), a short reaction time (as short as 2 h), and excellent N-monoalkylation selectivity.
Catalytic olefin hydroamination with aminium radical cations: A photoredox method for direct C-N bond formation
Musacchio, Andrew J.,Nguyen, Lucas Q.,Beard, G. Hudson,Knowles, Robert R.
, p. 12217 - 12220 (2014/12/09)
While olefin amination with aminium radical cations is a classical method for C-N bond formation, catalytic variants that utilize simple 2° amine precursors remain largely undeveloped. Herein we report a new visible-light photoredox protocol for the intramolecular anti-Markovnikov hydroamination of aryl olefins that proceeds through catalytically generated aminium radical intermediates. Mechanistic studies are consistent with a process involving amine oxidation via electron transfer, turnover-limiting C-N bond formation, and a second electron transfer step to reduce a carbon-centered radical, rendering the overall process redox-neutral. A range of structurally diverse N-aryl heterocycles can be prepared in good to excellent yields under conditions significantly milder than those required by conventional aminium-based protocols.
Pd(0)-catalyzed alkene oxy- and aminoalkynylation with aliphatic bromoacetylenes
Nicolai, Stefano,Sedigh-Zadeh, Raha,Waser, Jeroime
, p. 3783 - 3801 (2013/06/26)
Tetrahydrofurans and pyrrolidines are among the most important heterocycles found in bioactive compounds. Cyclization-functionalization domino reactions of alcohols or amines onto olefins constitute one of the most efficient methods to access them. In this context, oxy- and aminoalkynylation are especially important reactions, because of the numerous transformations possible with the triple bond of acetylenes, yet these methods have been limited to the use of silyl protected acetylenes. Herein, we report the first palladium-catalyzed oxy- and aminoalkynylation using aliphatic bromoalkynes, which proceeded with high diastereoselectivity and functional group tolerance. A one-pot hydrogenation of the triple bond gave then access to alkyl-substituted tetrahydrofurans and pyrroldines. Finally, a detailed study of the side products formed during the reaction gave a first insight into the reaction mechanism.
A new method for intramolecular chloroamination of unfunctionalized olefins
Liu, Gong-Qing,Li, Wei,Li, Yue-Ming
supporting information, p. 395 - 402 (2013/05/08)
A new method for the intramolecular chloroamination of unfunctionalized olefins is reported. The reactions were carried out at room temperature for 3 h using hydrated copper(II) chloride as both promoter and chlorine source, and the corresponding vincinal haloamines were obtained in good isolated yields.
