93407-33-1Relevant academic research and scientific papers
Direct Synthesis of α-Amino Nitriles from Sulfonamides via Base-Mediated C-H Cyanation
Shi, Shasha,Yang, Xianyu,Tang, Man,Hu, Jiefeng,Loh, Teck-Peng
, p. 4018 - 4022 (2021/05/26)
Herein, we disclose a transition-metal-free reaction system that enables α-cyanation of sulfonamides through C-H bond cleavage for the preparation of α-amino nitriles, including difficult-to-access all-alkyl α-tertiary scaffolds. More than 50 substrate examples prove a wide functional group tolerance. Additionally, its synthetic practicality is highlighted by gram-scalability and the late-stage modification of natural compounds. Mechanistic experiments suggest that this process involves in situ formation of an imine intermediate via base-promoted elimination of HF.
Site-Selective Electrochemical Benzylic C?H Amination
Hou, Zhong-Wei,Liu, Ding-Jin,Xiong, Peng,Lai, Xiao-Li,Song, Jinshuai,Xu, Hai-Chao
supporting information, p. 2943 - 2947 (2020/12/11)
C?H/N-H cross-coupling is an ideal strategy to synthesize various amines but remains challenging owing to the requirement for sacrificial chemical oxidants and the difficulty in controlling the regio- and chemo-selectivity. Herein we report a site-selective electrochemical amination reaction that can convert benzylic C?H bonds into C-N linkages via H2 evolution without need for external oxidants or metal catalysts. The synthetic strategy involves anodic cleavage of benzylic C?H to form a carbocation intermediate, which is then trapped with an amine nucleophile leading to C?N bond formation. Key to the success is to include HFIP as a co-solvent to modulate the oxidation potentials of the alkylbenzene substrate and the aminated product to avoid overoxidation of the latter.
Halogen-Bond-Induced Consecutive Csp3-H Aminations via Hydrogen Atom Transfer Relay Strategy
Alom, Nur-E,Ariyarathna, Jeewani P.,Bassiouni, Omar H.,Kaur, Navdeep,Kennell, Maureen L.,Li, Wei,Wu, Fan
, p. 2135 - 2140 (2020/04/09)
The utilization of a halogen bond in a number of chemical fields is well-known. Surprisingly, the incorporation of this useful noncovalent interaction in chemical reaction engineering is rare. We disclose here an uncommon use of halogen bonding to induce intermolecular Csp3-H amination while enabling a hydrogen atom transfer relay strategy to access privileged pyrrolidine structures directly from alkanes. Mechanistic studies support the presence of multiple halogen bond interactions at distinct reaction stages.
Organocatalytic nitrenoid transfer: Metal-free selective intermolecular C(sp3)-H amination catalyzed by an iminium salt
Combee, Logan A.,Raya, Balaram,Wang, Daoyong,Hilinski, Michael K.
, p. 935 - 939 (2018/02/07)
This report details the first organocatalytic method for nitrenoid transfer and its application to intermolecular, site-selective C(sp3)-H amination. The method utilizes a trifluoromethyl iminium salt as the catalyst, iminoiodinanes as the nitrogen source, and substrate as the limiting reagent. Activated, benzylic, and aliphatic substrates can all be selectively functionalized in yields up to 87%. A mechanistic proposal for the observed reactivity supported by experimental evidence invokes the intermediacy of a diaziridinium salt or related organic nitrenoid, species that have not been previously explored for the purpose of C-H amination. Finally, examples of late-stage functionalization of complex molecules highlight the selectivity and potential utility of this catalytic method in synthesis.
A Metal–Organic Framework with Exceptional Activity for C?H Bond Amination
Wang, Le,Agnew, Douglas W.,Yu, Xiao,Figueroa, Joshua S.,Cohen, Seth M.
supporting information, p. 511 - 515 (2018/02/21)
The development of catalysts capable of fast, robust C?H bond amination under mild conditions is an unrealized goal despite substantial progress in the field of C?H activation in recent years. A Mn-based metal–organic framework (CPF-5) is described that promotes the direct amination of C?H bonds with exceptional activity. CPF-5 is capable of functionalizing C?H bonds in an intermolecular fashion with unrivaled catalytic stability producing >105 turnovers.
Nondirected, cu-catalyzed sp3 C-H aminations with hydroxylamine-based amination reagents: Catalytic and mechanistic studies
Wang, Anqi,Venditto, Nicholas J.,Darcy, Julia W.,Emmert, Marion H.
, p. 1259 - 1268 (2017/05/29)
This work demonstrates the use of hydroxylamine-based amination reagents RSO2NH-OAc for the nondirected, Cu-catalyzed amination of benzylic C-H bonds. The amination reagents can be prepared on a gram scale, are benchtop stable, and provide benzylic C-H amination products with up to 86% yield. Mechanistic studies of the established reactivity with toluene as substrate reveal a ligand-promoted, Cu-catalyzed mechanism proceeding through Ph-CH2(NTsOAc) as a major intermediate. Stoichiometric reactivity of Ph-CH2(NTsOAc) to produce Ph-CH2-NHTs suggests a two-cycle, radical pathway for C-H amination, in which the decomposition of the employed diimine ligands plays an important role.
Catalytic Carbocation Generation Enabled by the Mesolytic Cleavage of Alkoxyamine Radical Cations
Zhu, Qilei,Gentry, Emily C.,Knowles, Robert R.
supporting information, p. 9969 - 9973 (2016/08/16)
A new catalytic method is described to access carbocation intermediates via the mesolytic cleavage of alkoxyamine radical cations. In this process, electron transfer between an excited state oxidant and a TEMPO-derived alkoxyamine substrate gives rise to a radical cation with a remarkably weak C?O bond. Spontaneous scission results in the formation of the stable nitroxyl radical TEMPO.as well as a reactive carbocation intermediate that can be intercepted by a wide range of nucleophiles. Notably, this process occurs under neutral conditions and at comparatively mild potentials, enabling catalytic cation generation in the presence of both acid sensitive and easily oxidized nucleophilic partners.
Alkylation of Sulfonamides with Trichloroacetimidates under Thermal Conditions
Wallach, Daniel R.,Chisholm, John D.
, p. 8035 - 8042 (2016/09/12)
An intermolecular alkylation of sulfonamides with trichloroacetimidates is reported. This transformation does not require an exogenous acid, base, or transition metal catalyst; instead the addition occurs in refluxing toluene without additives. The sulfonamide alkylation partner appears to be only limited by sterics, with unsubstituted sulfonamides providing better yields than more encumbered N-alkyl sulfonamides. The trichloroacetimidate alkylating agent must be a stable cation precursor for the substitution reaction to proceed under these conditions.
Iron-catalyzed efficient intermolecular amination of C(sp3)-H bonds with bromamine-T as nitrene source
Wang, Haiyu,Li, Yuxi,Wang, Zhiming,Lou, Jun,Xiao, Yuling,Qiu, Guofu,Hu, Xianming,Altenbach, Hans-Josef,Liu, Peng
, p. 25287 - 25290 (2014/07/07)
[Fe(N4Py)(CH3CN)](ClO4)2 can efficiently catalyze intermolecular nitrene insertion of sp3 C-H bonds with bromamine-T as the nitrene source, forming the desired tosylprotected amines with NaBr as the by-product.
A versatile tripodal Cu(I) reagent for C-N bond construction via nitrene-transfer chemistry: Catalytic perspectives and mechanistic insights on C-H aminations/amidinations and olefin aziridinations
Bagchi, Vivek,Paraskevopoulou, Patrina,Das, Purak,Chi, Lingyu,Wang, Qiuwen,Choudhury, Amitava,Mathieson, Jennifer S.,Cronin, Leroy,Pardue, Daniel B.,Cundari, Thomas R.,Mitrikas, George,Sanakis, Yiannis,Stavropoulos, Pericles
supporting information, p. 11362 - 11381 (2014/09/17)
A CuI catalyst (1), supported by a framework of strongly basic guanidinato moieties, mediates nitrene-transfer from PhI=NR sources to a wide variety of aliphatic hydrocarbons (C-H amination or amidination in the presence of nitriles) and olefins (aziridination). Product profiles are consistent with a stepwise rather than concerted C-N bond formation. Mechanistic investigations with the aid of Hammett plots, kinetic isotope effects, labeled stereochemical probes, and radical traps and clocks allow us to conclude that carboradical intermediates play a major role and are generated by hydrogen-atom abstraction from substrate C-H bonds or initial nitrene-addition to one of the olefinic carbons. Subsequent processes include solvent-caged radical recombination to afford the major amination and aziridination products but also one-electron oxidation of diffusively free carboradicals to generate amidination products due to carbocation participation. Analyses of metal- and ligand-centered events by variable temperature electrospray mass spectrometry, cyclic voltammetry, and electron paramagnetic resonance spectroscopy, coupled with computational studies, indicate that an active, but still elusive, copper-nitrene (S = 1) intermediate initially abstracts a hydrogen atom from, or adds nitrene to, C-H and C=C bonds, respectively, followed by a spin flip and radical rebound to afford intra- and intermolecular C-N containing products.
