Login Register Cart 0
Generic placeholder image

Current Organic Chemistry

Editor-in-Chief

ISSN (Print): 1385-2728
ISSN (Online): 1875-5348

Back
Journal Home About Journal Editorial Board Journal Insight Current Issue Volumes/Issues
Subscribe
Review Article

At the Speed of Light: Recent Advances on Photocatalyzed Generation and Applications of Iminyl Radicals Promoted by Visible-light

Author(s): Mario Valle-Sánchez, Osvaldo F. López-Saladino, Nelly González-Rivas, Yoxkin Estévez-Martínez, Bernardo A. Frontana-Uribe and Erick Cuevas-Yañez*

Volume 28, Issue 18, 2024

Published on: 11 June, 2024

Page: [1404 - 1436] Pages: 33

DOI: 10.2174/0113852728301428240517115907

Price: $65

Abstract

Nitrogen-positioned radicals are chemical entities that have a lengthier history than carbon ones and their high reactivity makes them invaluable. But, despite its power, much of its chemistry is still uncharted. Currently, developed methodologies to access nitrogen-positioned radicals, such as transition metal catalysis or visible-light photoredox methods through a single-electron transfer process, avoiding the use of harmful or toxic reagents, excess raw materials, solvents as well as pre-functionalization steps or extensive synthetic routes are in continuous progress. This revision aims to depict the recent advances in the field of iminyl-radicals’ syntheses, a special class of radicals placed on nitrogen, catalyzed by transition metals or photoredox techniques for the construction of C-N bonds and their synthetic applications. This work serves as a comprehensive guide for the scope of synthetic applications that this kind of radicals could have.

« Previous Next »
Graphical Abstract

[1]
Joule, J.A.; Mills, K. Heterocyclic Chemistry; Wiley: Hoboken, New Jersey, 2013, p. 720.
[2]
Zard, S.Z. Recent progress in the generation and use of nitrogen-centred radicals. Chem. Soc. Rev., 2008, 37(8), 1603-1618.
[http://dx.doi.org/10.1039/b613443m] [PMID: 18648685]
[3]
Jiang, H.; An, X.; Tong, K.; Zheng, T.; Zhang, Y.; Yu, S. Visible-light-promoted iminyl-radical formation from acyl oximes: A unified approach to pyridines, quinolines, and phenanthridines. Angew. Chem. Int. Ed., 2015, 54(13), 4055-4059.
[http://dx.doi.org/10.1002/anie.201411342] [PMID: 25650356]
[4]
Shimbayashi, T.; Nakamoto, D.; Okamoto, K.; Ohe, K. Facile construction of tetrahydropyrrolizines by iron-catalyzed double cyclization of alkene-tethered oxime esters with 1,2-disubstituted alkenes. Org. Lett., 2018, 20(10), 3044-3048.
[http://dx.doi.org/10.1021/acs.orglett.8b01073] [PMID: 29737175]
[5]
Forrester, A.R.; Gill, M.; Thomson, R.H. Synthetic reactions with iminyl radicals. J. Chem. Soc. Chem. Commun., 1976, (17), 677.
[http://dx.doi.org/10.1039/c39760000677]
[6]
Boivin, J.; Fouquet, E.; Zard, S.Z. Ring opening induced by iminyl radicals derived from cyclobutanones: New aspects of tin hydride cleavage of S-phenyl sulfenylimines. J. Am. Chem. Soc., 1991, 113(3), 1055-1057.
[http://dx.doi.org/10.1021/ja00003a057]
[7]
Li, L.; Chen, H.; Mei, M.; Zhou, L. Visible-light promoted γ-cyanoalkyl radical generation: Three-component cyanopropylation/etherification of unactivated alkenes. Chem. Commun. (Camb.), 2017, 53(84), 11544-11547.
[http://dx.doi.org/10.1039/C7CC07347J] [PMID: 28990024]
[8]
Dauncey, E.M.; Morcillo, S.P.; Douglas, J.J.; Sheikh, N.S.; Leonori, D. Photoinduced remote functionalisations by iminyl radical promoted C-C and C-H Bond cleavage cascades. Angew. Chem. Int. Ed., 2018, 57(3), 744-748.
[http://dx.doi.org/10.1002/anie.201710790] [PMID: 29114978]
[9]
Le Vaillant, F.; Garreau, M.; Nicolai, S.; Gryn’ova, G.; Corminboeuf, C.; Waser, J. Fine-tuned organic photoredox catalysts for fragmentation-alkynylation cascades of cyclic oxime ethers. Chem. Sci. (Camb.), 2018, 9(27), 5883-5889.
[http://dx.doi.org/10.1039/C8SC01818A] [PMID: 30079201]
[10]
Nishimura, T.; Uemura, S. Palladium(0)-catalyzed ring cleavage of cyclobutanone oximes leading to nitriles via β-carbon elimination. J. Am. Chem. Soc., 2000, 122(48), 12049-12050.
[http://dx.doi.org/10.1021/ja005558l]
[11]
Uchiyama, K.; Hayashi, Y.; Narasaka, K. Synthesis of dihydropyrroles by the intramolecular addition of alkylideneaminyl radicals generated from O-2,4-dinitrophenyloximes of γ,δ-unsaturated ketones. Chem. Lett., 1998, 27(12), 1261-1262.
[http://dx.doi.org/10.1246/cl.1998.1261]
[12]
Castle, S.; Jackman, M.; Cai, Y. Recent advances in iminyl radical cyclizations. Synthesis, 2017, 49(8), 1785-1795.
[http://dx.doi.org/10.1055/s-0036-1588707]
[13]
McBurney, R.T.; Slawin, A.M.Z.; Smart, L.A.; Yu, Y.; Walton, J.C. UV promoted phenanthridine syntheses from oxime carbonate derived iminyl radicals. Chem. Commun. (Camb.), 2011, 47(28), 7974-7976.
[http://dx.doi.org/10.1039/c1cc12720a] [PMID: 21677988]
[14]
Davies, J.; Sheikh, N.S.; Leonori, D. Photoredox imino functionalizations of Olefins. Angew. Chem. Int. Ed., 2017, 56(43), 13361-13365.
[http://dx.doi.org/10.1002/anie.201708497] [PMID: 28857386]
[15]
Cai, Y.; Jalan, A.; Kubosumi, A.R.; Castle, S.L. Microwave-promoted tin-free iminyl radical cyclization with TEMPO trapping: A practical synthesis of 2-acylpyrroles. Org. Lett., 2015, 17(3), 488-491.
[http://dx.doi.org/10.1021/ol5035047] [PMID: 25594391]
[16]
Singh, J.; Nelson, T.J.; Mansfield, S.A.; Nickel, G.A.; Cai, Y.; Jones, D.D.; Small, J.E.; Ess, D.H.; Castle, S.L. Microwave- and thermally promoted iminyl radical cyclizations: A versatile method for the synthesis of functionalized pyrrolines. J. Org. Chem., 2022, 87(24), 16250-16262.
[http://dx.doi.org/10.1021/acs.joc.2c01806] [PMID: 36472924]
[17]
Zhao, H.B.; Hou, Z.W.; Liu, Z.J.; Zhou, Z.F.; Song, J.; Xu, H.C. Amidinyl radical formation through anodic N-H Bond cleavage and its application in aromatic C-H bond functionalization. Angew. Chem. Int. Ed., 2017, 56(2), 587-590.
[http://dx.doi.org/10.1002/anie.201610715] [PMID: 27936308]
[18]
Wang, F.; Gerken, J.B.; Bates, D.M.; Kim, Y.J.; Stahl, S.S. Electrochemical strategy for hydrazine synthesis: Development and overpotential analysis of methods for oxidative N-N coupling of an ammonia surrogate. J. Am. Chem. Soc., 2020, 142(28), 12349-12356.
[http://dx.doi.org/10.1021/jacs.0c04626] [PMID: 32520537]
[19]
Yin, W.; Wang, X. Recent advances in iminyl radical-mediated catalytic cyclizations and ring-opening reactions. New J. Chem., 2019, 43(8), 3254-3264.
[http://dx.doi.org/10.1039/C8NJ06165C]
[20]
Krylov, I.B.; Segida, O.O.; Budnikov, A.S.; Terent’ev, A.O. Oxime‐derived iminyl radicals in selective processes of hydrogen atom transfer and addition to carbon‐carbon π‐bonds. Adv. Synth. Catal., 2021, 363(10), 2502-2528.
[http://dx.doi.org/10.1002/adsc.202100058]
[21]
Yang, H.B.; Selander, N. Divergent iron‐catalyzed coupling of O ‐acyloximes with silyl enol ethers. Chemistry, 2017, 23(8), 1779-1783.
[http://dx.doi.org/10.1002/chem.201605636] [PMID: 27995682]
[22]
Zhao, B.; Shi, Z. Copper‐catalyzed intermolecular heck‐like coupling of cyclobutanone oximes initiated by selective C-C bond cleavage. Angew. Chem. Int. Ed., 2017, 56(41), 12727-12731.
[http://dx.doi.org/10.1002/anie.201707181] [PMID: 28861945]
[23]
Morcillo, S.P.; Dauncey, E.M.; Kim, J.H.; Douglas, J.J.; Sheikh, N.S.; Leonori, D. Photoinduced remote functionalization of amides and amines using electrophilic nitrogen radicals. Angew. Chem. Int. Ed., 2018, 57(39), 12945-12949.
[http://dx.doi.org/10.1002/anie.201807941] [PMID: 30074300]
[24]
Yu, X.Y.; Chen, J.R.; Wang, P.Z.; Yang, M.N.; Liang, D.; Xiao, W.J. A visible‐light‐driven iminyl radical‐mediated C-C single bond cleavage/radical addition cascade of oxime esters. Angew. Chem. Int. Ed., 2018, 57(3), 738-743.
[http://dx.doi.org/10.1002/anie.201710618] [PMID: 29214705]
[25]
Ai, W.; Liu, Y.; Wang, Q.; Lu, Z.; Liu, Q. Cu-catalyzed redox-neutral ring cleavage of cycloketone O -acyl oximes: Chemodivergent access to distal oxygenated nitriles. Org. Lett., 2018, 20(2), 409-412.
[http://dx.doi.org/10.1021/acs.orglett.7b03707] [PMID: 29297695]
[26]
Zhao, Y.; Xia, W. Recent advances in radical-based C-N bond formation via photo-/electrochemistry. Chem. Soc. Rev., 2018, 47(8), 2591-2608.
[http://dx.doi.org/10.1039/C7CS00572E] [PMID: 29619455]
[27]
Wappes, E.A.; Nakafuku, K.M.; Nagib, D.A. Directed β C-H amination of alcohols via radical relay chaperones. J. Am. Chem. Soc., 2017, 139(30), 10204-10207.
[http://dx.doi.org/10.1021/jacs.7b05214] [PMID: 28741940]
[28]
Jiang, H.; Studer, A. α‐Aminoxy‐acid‐auxiliary‐enabled intermolecular radical γ‐C(sp3)-H Functionalization of ketones. Angew. Chem. Int. Ed., 2018, 57(6), 1692-1696.
[http://dx.doi.org/10.1002/anie.201712066] [PMID: 29266582]
[29]
Lu, B.; Cheng, Y.; Chen, L.Y.; Chen, J.R.; Xiao, W.J. Photoinduced copper-catalyzed radical aminocarbonylation of cycloketone oxime esters. ACS Catal., 2019, 9(9), 8159-8164.
[http://dx.doi.org/10.1021/acscatal.9b02830]
[30]
He, B.Q.; Yu, X.Y.; Wang, P.Z.; Chen, J.R.; Xiao, W.J. A photoredox catalyzed iminyl radical-triggered C-C bond cleavage/addition/Kornblum oxidation cascade of oxime esters and styrenes: Synthesis of ketonitriles. Chem. Commun. (Camb.), 2018, 54(86), 12262-12265.
[http://dx.doi.org/10.1039/C8CC07072E] [PMID: 30318535]
[31]
Zhang, J.J.; Duan, X.H.; Wu, Y.; Yang, J.C.; Guo, L.N. Transition-metal free C-C bond cleavage/borylation of cycloketone oxime esters. Chem. Sci. (Camb.), 2019, 10(1), 161-166.
[http://dx.doi.org/10.1039/C8SC03315C] [PMID: 30713627]
[32]
Fleming, F.F.; Yao, L.; Ravikumar, P.C.; Funk, L.; Shook, B.C. Nitrile-containing pharmaceuticals: Efficacious roles of the nitrile pharmacophore. J. Med. Chem., 2010, 53(22), 7902-7917.
[http://dx.doi.org/10.1021/jm100762r] [PMID: 20804202]
[33]
Rappoport, Z. Chemistry of Functional Groups : A series of advanced treatises; Wiley: Hoboken, New Jersey, 1970.
[34]
López, R.; Palomo, C. Cyanoalkylation: Alkylnitriles in catalytic C-C bond‐forming reactions. Angew. Chem. Int. Ed., 2015, 54(45), 13170-13184.
[http://dx.doi.org/10.1002/anie.201502493] [PMID: 26387483]
[35]
Taylor, A.P.; Robinson, R.P.; Fobian, Y.M.; Blakemore, D.C.; Jones, L.H.; Fadeyi, O. Modern advances in heterocyclic chemistry in drug discovery. Org. Biomol. Chem., 2016, 14(28), 6611-6637.
[http://dx.doi.org/10.1039/C6OB00936K] [PMID: 27282396]
[36]
Shen, X.; Zhao, J.J.; Yu, S. Photoredox-catalyzed intermolecular remote C-H and C-C vinylation via iminyl radicals. Org. Lett., 2018, 20(17), 5523-5527.
[http://dx.doi.org/10.1021/acs.orglett.8b02540] [PMID: 30136853]
[37]
Jiang, H.; Studer, A. Iminyl‐radicals by oxidation of α‐imino‐oxy acids: Photoredox‐neutral alkene carboimination for the synthesis of pyrrolines. Angew. Chem. Int. Ed., 2017, 56(40), 12273-12276.
[http://dx.doi.org/10.1002/anie.201706270] [PMID: 28783243]
[38]
Yan, X.; Li, X.; Wang, Y.; Dai, Y.; Yan, X.; Zhao, D.; Xu, X. Iminyl-radical-mediated C-C cleavage/amination and alkene iminoamination enabled by visible-light-induced cerium catalysis. ACS Sustain. Chem.& Eng., 2021, 9(1), 101-105.
[http://dx.doi.org/10.1021/acssuschemeng.0c07850]
[39]
Singh, J.; Jones, S.A.; Nelson, T.J.; Botello, J.A.; Castle, S.L. Formal γ-C(sp3)-H activation of ketones via microwave-promoted and iminyl-radical-mediated 1,5-hydrogen atom transfer. J. Org. Chem., 2023, 88(14), 10287-10297.
[http://dx.doi.org/10.1021/acs.joc.3c00915] [PMID: 37390469]
[40]
Gholami, F.; Yousefnejad, F.; Larijani, B.; Mahdavi, M. Vinyl azides in organic synthesis: An overview. RSC Advances, 2023, 13(2), 990-1018.
[http://dx.doi.org/10.1039/D2RA06726A] [PMID: 36686934]
[41]
Wang, Q.; Huang, J.; Zhou, L. Synthesis of quinolines by visible‐light induced radical reaction of vinyl azides and α‐carbonyl benzyl bromides. Adv. Synth. Catal., 2015, 357(11), 2479-2484.
[http://dx.doi.org/10.1002/adsc.201500141]
[42]
Feng, L.; Yang, C.; Xia, W. Visible-light promoted selective imination of unactivated C-H bonds via copper-nitrene intermediates for the synthesis of 2 H -azirines. Org. Lett., 2019, 21(20), 8323-8327.
[http://dx.doi.org/10.1021/acs.orglett.9b03103] [PMID: 31584285]
[43]
Chakrabarty, A.; Mukherjee, S. Iridium‐catalyzed enantioselective and chemodivergent allenylic alkylation of vinyl azides for the synthesis of α‐allenylic amides and ketones**. Angew. Chem. Int. Ed., 2022, 61(12), e202115821.
[http://dx.doi.org/10.1002/anie.202115821] [PMID: 35044711]
[44]
Paveliev, S.A.; Segida, O.O.; Mulina, O.M.; Krylov, I.B.; Terent’ev, A.O. Decatungstate-catalyzed photochemical synthesis of enaminones from vinyl azides and aldehydes. Org. Lett., 2022, 24(49), 8942-8947.
[http://dx.doi.org/10.1021/acs.orglett.2c03364] [PMID: 36399327]
[45]
Fang, Z.; Zhang, Y.; Zhang, Z.; Song, Q.; Wu, Y.; Liu, Z.; Ning, Y. Synthesis of gem -Disulfonyl enamines via an iminyl-radical-mediated formal 1,3-HAT/radical coupling cascade. Org. Lett., 2022, 24(35), 6374-6379.
[http://dx.doi.org/10.1021/acs.orglett.2c02277] [PMID: 36018352]
[46]
Zhang, J.; Li, X.; Xie, W.; Ye, S.; Wu, J. Photoredox-catalyzed sulfonylation of O-Acyl oximes via iminyl radicals with the insertion of sulfur dioxide. Org. Lett., 2019, 21(13), 4950-4954.
[http://dx.doi.org/10.1021/acs.orglett.9b01323] [PMID: 31179704]
[47]
Wang, P.Z.; Yu, X.Y.; Li, C.Y.; He, B.Q.; Chen, J.R.; Xiao, W.J. A photocatalytic iminyl radical-mediated C-C bond cleavage/addition/cyclization cascade for the synthesis of 1,2,3,4-tetrahydrophenanthrenes. Chem. Commun. (Camb.), 2018, 54(71), 9925-9928.
[http://dx.doi.org/10.1039/C8CC06145A] [PMID: 30116806]
[48]
Xia, P.J.; Ye, Z.P.; Hu, Y.Z.; Song, D.; Xiang, H.Y.; Chen, X.Q.; Yang, H. Photocatalytic, phosphoranyl radical-mediated N-O cleavage of strained cycloketone oximes. Org. Lett., 2019, 21(8), 2658-2662.
[http://dx.doi.org/10.1021/acs.orglett.9b00651] [PMID: 30942601]
[49]
Jiang, Y.S.; Liu, F.; Huang, M.S.; Luo, X.L.; Xia, P.J. Photocatalytic modular cyanoalkylamination of alkenes involving two different iminyl radicals. Org. Lett., 2022, 24(43), 8019-8024.
[http://dx.doi.org/10.1021/acs.orglett.2c03233] [PMID: 36264241]
[50]
Zhao, B.; Tan, H.; Chen, C.; Jiao, N.; Shi, Z. Photoinduced C-C bond cleavage and oxidation of cycloketoxime esters. Chin. J. Chem., 2018, 36(11), 995-999.
[http://dx.doi.org/10.1002/cjoc.201800206]
[51]
Yuan, Y.; Dong, W.H.; Gao, X.S.; Xie, X.M.; Zhang, Z.G. Visible-light-induced radical cascade cyclization of oxime esters and aryl isonitriles: Synthesis of cyclopenta[b]quinoxalines. Chem. Commun. (Camb.), 2019, 55(79), 11900-11903.
[http://dx.doi.org/10.1039/C9CC05655F] [PMID: 31528936]
[52]
Yu, X.Y.; Wang, P.Z.; Yan, D.M.; Lu, B.; Chen, J.R.; Xiao, W.J. Photocatalytic neophyl rearrangement and reduction of distal carbon radicals by iminyl radical‐mediated C-C bond cleavage. Adv. Synth. Catal., 2018, 360(18), 3601-3606.
[http://dx.doi.org/10.1002/adsc.201800834]
[53]
Jian, Y.; Chen, M.; Yang, C.; Xia, W. Minisci‐type C-H cyanoalkylation of heteroarenes through N-O/C-C bonds cleavage. Eur. J. Org. Chem., 2020, 2020(10), 1439-1442.
[http://dx.doi.org/10.1002/ejoc.201900406]
[54]
Ma, Z.Y.; Guo, L.N.; Gu, Y.R.; Chen, L.; Duan, X.H. Iminyl radical‐mediated controlled hydroxyalkylation of remote C(sp3)‐H bond via tandem 1,5‐HAT and difunctionalization of aryl alkenes. Adv. Synth. Catal., 2018, 360(22), 4341-4347.
[http://dx.doi.org/10.1002/adsc.201801198]
[55]
Xia, P.J.; Hu, Y.Z.; Ye, Z.P.; Li, X.J.; Xiang, H.Y.; Yang, H. O-Perfluoropyridin-4-yl Oximes: Iminyl radical precursors for photo- or thermal-induced N-O Cleavage in C(sp2)-C(sp3) bond formation. J. Org. Chem., 2020, 85(5), 3538-3547.
[http://dx.doi.org/10.1021/acs.joc.9b03251] [PMID: 31971800]
[56]
Dauncey, E.M.; Dighe, S.U.; Douglas, J.J.; Leonori, D. A dual photoredox-nickel strategy for remote functionalization via iminyl radicals: Radical ring-opening-arylation, -vinylation and -alkylation cascades. Chem. Sci. (Camb.), 2019, 10(33), 7728-7733.
[http://dx.doi.org/10.1039/C9SC02616A] [PMID: 32180920]
[57]
Li, Y.H.; Wang, C.H.; Gao, S.Q.; Qi, F.M.; Yang, S.D. Visible photocatalysis of novel oxime phosphonates: Synthesis of β-aminophosphonates. Chem. Commun. (Camb.), 2019, 55(79), 11888-11891.
[http://dx.doi.org/10.1039/C9CC06075H] [PMID: 31528874]
[58]
Shu, W.; Nevado, C. Visible‐light‐mediated remote aliphatic C-H functionalizations through a 1,5‐hydrogen transfer cascade. Angew. Chem. Int. Ed., 2017, 56(7), 1881-1884.
[http://dx.doi.org/10.1002/anie.201609885] [PMID: 28097790]
[59]
Liu, Z.; Shen, H.; Xiao, H.; Wang, Z.; Zhu, L.; Li, C. Copper-catalyzed ring-opening radical trifluoromethylation of cycloalkanone oximes. Org. Lett., 2019, 21(13), 5201-5205.
[http://dx.doi.org/10.1021/acs.orglett.9b01803] [PMID: 31247800]
[60]
Chen, J.; Wang, P.Z.; Lu, B.; Liang, D.; Yu, X.Y.; Xiao, W.J.; Chen, J.R. Enantioselective radical ring-opening cyanation of oxime esters by dual photoredox and copper catalysis. Org. Lett., 2019, 21(23), 9763-9768.
[http://dx.doi.org/10.1021/acs.orglett.9b03970] [PMID: 31746212]
[61]
Chen, J.; He, B.Q.; Wang, P.Z.; Yu, X.Y.; Zhao, Q.Q.; Chen, J.R.; Xiao, W.J. Photoinduced, copper-catalyzed radical cross-coupling of cycloketone oxime esters, alkenes, and terminal alkynes. Org. Lett., 2019, 21(11), 4359-4364.
[http://dx.doi.org/10.1021/acs.orglett.9b01529] [PMID: 31141377]
[62]
Lei, W.L.; Feng, K.W.; Wang, T.; Wu, L.Z.; Liu, Q. Eosin Y- and copper-catalyzed dark reaction to construct Ene-γ-Lactams. Org. Lett., 2018, 20(22), 7220-7224.
[http://dx.doi.org/10.1021/acs.orglett.8b03147] [PMID: 30403485]
[63]
Zhang, J.Y.; Duan, X.H.; Yang, J.C.; Guo, L.N. Redox-neutral cyanoalkylation/cyclization of olefinic 1,3-dicarbonyls with cycloketone oxime esters: Access to cyanoalkylated dihydrofurans. J. Org. Chem., 2018, 83(7), 4239-4249.
[http://dx.doi.org/10.1021/acs.joc.8b00271] [PMID: 29557652]
[64]
Yu, X.Y.; Zhao, Q.Q.; Chen, J.; Chen, J.R.; Xiao, W.J. Copper‐catalyzed radical cross‐coupling of redox‐active oxime esters, styrenes, and boronic acids. Angew. Chem. Int. Ed., 2018, 57(47), 15505-15509.
[http://dx.doi.org/10.1002/anie.201809820] [PMID: 30295976]
[65]
Lou, J.; He, Y.; Li, Y.; Yu, Z. Transition‐metal‐promoted direct C-H cyanoalkylation and cyanoalkoxylation of internal alkenes via radical C-C bond cleavage of cycloketone oxime esters. Adv. Synth. Catal., 2019, 361(16), 3787-3799.
[http://dx.doi.org/10.1002/adsc.201900402]
[66]
Wang, P.; Zhao, B.; Yuan, Y.; Shi, Z. Radical-induced ring-opening and reconstruction of cyclobutanone oxime esters. Chem. Commun. (Camb.), 2019, 55(13), 1971-1974.
[http://dx.doi.org/10.1039/C8CC10109D] [PMID: 30681675]
[67]
Tian, L.; Gao, S.; Wang, R.; Li, Y.; Tang, C.; Shi, L.; Fu, J. Copper-catalyzed ring-opening C(sp3)-N coupling of cycloketone oxime esters: Access to 1°, 2° and 3° alkyl amines. Chem. Commun. (Camb.), 2019, 55(37), 5347-5350.
[http://dx.doi.org/10.1039/C9CC02030F] [PMID: 30994128]
[68]
Wu, J.; Zhang, J.Y.; Gao, P.; Xu, S.L.; Guo, L.N. Copper-catalyzed redox-neutral cyanoalkylarylation of activated alkenes with cyclobutanone oxime esters. J. Org. Chem., 2018, 83(2), 1046-1055.
[http://dx.doi.org/10.1021/acs.joc.7b02714] [PMID: 29239182]
[69]
Tu, J.L.; Tang, W.; Xu, W.; Liu, F. Iminyl-radical-promoted C-C bond cleavage/heck-like coupling via dual cobaloxime and photoredox catalysis. J. Org. Chem., 2021, 86(3), 2929-2940.
[http://dx.doi.org/10.1021/acs.joc.0c02834] [PMID: 33481602]
[70]
Ma, B.; Xia, Q.; Wang, D.; Jin, J.K.; Li, Z.; Liang, Q.J.; Sun, M.Y.; Liu, D.; Liu, L.J.; Shu, H.X.; Yang, J.; Li, D.; He, J. Metal‐organic framework supported copper photoredox catalysts for iminyl radical‐mediated reactions. Angew. Chem. Int. Ed., 2023, 62(21), e202300233.
[http://dx.doi.org/10.1002/anie.202300233] [PMID: 36896733]
[71]
Xiao, T.; Zhou, L.; Huang, H.; Anand, D. Iminyl-radical-triggered C-C bond cleavage of cycloketone oxime derivatives: Generation of distal cyano-substituted alkyl radicals and their functionalization. Synthesis, 2020, 52(11), 1585-1601.
[http://dx.doi.org/10.1055/s-0039-1690844]
[72]
Zhao, J.F.; Duan, X.H.; Gu, Y.R.; Gao, P.; Guo, L.N. Iron-catalyzed decarboxylative olefination of cycloketone oxime esters with α,β-unsaturated carboxylic acids via C-C bond cleavage. Org. Lett., 2018, 20(15), 4614-4617.
[http://dx.doi.org/10.1021/acs.orglett.8b01901] [PMID: 30024173]
[73]
Yang, L.; Gao, P.; Duan, X.H.; Gu, Y.R.; Guo, L.N. Direct C-H cyanoalkylation of quinoxalin-2(1 H)-ones via radical C-C bond cleavage. Org. Lett., 2018, 20(4), 1034-1037.
[http://dx.doi.org/10.1021/acs.orglett.7b03984] [PMID: 29364685]
[74]
Terhorst, S.; Tiwari, D.P.; Meister, D.; Petran, B.; Rissanen, K.; Bolm, C. Syntheses of trifluoroethylated n-heterocycles from vinyl azides and togni’s reagent involving 1, N-hydrogen-atom transfer reactions. Org. Lett., 2020, 22(12), 4766-4770.
[http://dx.doi.org/10.1021/acs.orglett.0c01566] [PMID: 32496070]
[75]
Chen, B.; Guo, S.; Guo, X.; Zhang, G.; Yu, Y. Selective access to 4-substituted 2-aminothiazoles and 4-substituted 5-thiocyano-2-aminothiazoles from vinyl azides and potassium thiocyanate switched by palladium and iron catalysts. Org. Lett., 2015, 17(19), 4698-4701.
[http://dx.doi.org/10.1021/acs.orglett.5b02152] [PMID: 26372853]
[76]
Li, W.; Zhou, P.; Zhao, Q.; Lin, K.; Zhu, T. Carbene-catalyzed [3 + 2 + 1] annulation via C-N radical coupling of iminyl radicals and ketyl radicals. Org. Biomol. Chem., 2023, 21(18), 3784-3788.
[http://dx.doi.org/10.1039/D3OB00468F] [PMID: 37092356]
[77]
Zhao, X.; Liang, S.; Fan, X.; Yang, T.; Yu, W. Correction to “iron-catalyzed intramolecular C-H amination of α-azidyl amides”. Org. Lett., 2020, 22(6), 2500-2500.
[http://dx.doi.org/10.1021/acs.orglett.0c00658] [PMID: 32109078]
[78]
Zhang, Y.; Yin, Z.; Wu, X.F. Iron‐catalyzed synthesis of dihydronaphthalenones from aromatic oxime esters. Adv. Synth. Catal., 2019, 361(13), 3223-3227.
[http://dx.doi.org/10.1002/adsc.201900283]
[79]
Yin, Z.; Zhang, Z.; Zhang, Y.; Dixneuf, P.H.; Wu, X.F. Carbonylation of tertiary carbon radicals: Synthesis of lactams. Chem. Commun. (Camb.), 2019, 55(32), 4655-4658.
[http://dx.doi.org/10.1039/C9CC02112D] [PMID: 30932101]
[80]
Zhao, J.F.; Gao, P.; Duan, X.H.; Guo, L.N. Iron‐catalyzed ring‐opening/allylation of cyclobutanone oxime esters with allylic sulfones. Adv. Synth. Catal., 2018, 360(9), 1775-1779.
[http://dx.doi.org/10.1002/adsc.201701630]
[81]
Gu, Y.R.; Duan, X.H.; Chen, L.; Ma, Z.Y.; Gao, P.; Guo, L.N. Iminyl radical-triggered intermolecular distal C(sp3)-H Heteroarylation via 1,5-Hydrogen-Atom Transfer (HAT). Cascade. Org. Lett., 2019, 21(4), 917-920.
[http://dx.doi.org/10.1021/acs.orglett.8b03865] [PMID: 30688076]
[82]
Shimbayashi, T.; Okamoto, K.; Ohe, K. Iron‐catalyzed aminative cyclization/intermolecular homolytic aromatic substitution using oxime esters and simple arenes. Chem. Asian J., 2018, 13(4), 395-399.
[http://dx.doi.org/10.1002/asia.201701634] [PMID: 29239105]
[83]
Gu, Y.R.; Duan, X.H.; Yang, L.; Guo, L.N. Direct C-H cyanoalkylation of heteroaromatic N -oxides and quinones via C-C bond cleavage of cyclobutanone oximes. Org. Lett., 2017, 19(21), 5908-5911.
[http://dx.doi.org/10.1021/acs.orglett.7b02902] [PMID: 29072466]
[84]
Tang, Y.Q.; Yang, J.C.; Wang, L.; Fan, M.; Guo, L.N. Ni-catalyzed redox-neutral ring-opening/radical addition/ring-closing cascade of cycloketone oxime esters and vinyl azides. Org. Lett., 2019, 21(13), 5178-5182.
[http://dx.doi.org/10.1021/acs.orglett.9b01773] [PMID: 31247761]
[85]
Yu, J.X.; Teng, F.; Xiang, J.N.; Deng, W.; Li, J.H. One-carbon incorporation using cyclobutanone oxime ester enabled [2 + 2 + 1] carboannulation of 1,7-enynes by C-C/N-O bond cleavage and C-H functionalization. Org. Lett., 2019, 21(23), 9434-9437.
[http://dx.doi.org/10.1021/acs.orglett.9b03643] [PMID: 31762279]
[86]
Jiang, K.; Li, S.J.; Liu, Q.P.; Yu, N.; Li, Y.L.; Zhou, Y.Q.; He, K.C.; Lin, J.; Zheng, T.Y.; Lang, J.; Lan, Y.; Wei, Y. Iminyl radical-triggered relay annulation for the construction of bridged aza-tetracycles bearing four contiguous stereogenic centers. Chem. Sci. (Camb.), 2022, 13(24), 7283-7288.
[http://dx.doi.org/10.1039/D2SC01548J] [PMID: 35799821]
[87]
Li, X.; Yan, X.; Wang, Z.; He, X.; Dai, Y.; Yan, X.; Zhao, D.; Xu, X. Complementary oxidative generation of iminyl radicals from α-imino-oxy acids: Silver-catalyzed C-H Cyanoalkylation of Heterocycles and Quinones. J. Org. Chem., 2020, 85(4), 2504-2511.
[http://dx.doi.org/10.1021/acs.joc.9b03204] [PMID: 31910620]
[88]
Tang, J.; Sivaguru, P.; Ning, Y.; Zanoni, G.; Bi, X. Silver-catalyzed tandem C≡C bond hydroazidation/radical addition/cyclization of biphenyl acetylene: One-pot synthesis of 6-methyl sulfonylated phenanthridines. Org. Lett., 2017, 19(15), 4026-4029.
[http://dx.doi.org/10.1021/acs.orglett.7b01771] [PMID: 28737404]
[89]
Huang, F.; Zhang, S. Iminyl Radicals by reductive cleavage of N-O bond in oxime ether promoted by SmI2: A straightforward synthesis of five-membered cyclic imines. Org. Lett., 2019, 21(18), 7430-7434.
[http://dx.doi.org/10.1021/acs.orglett.9b02740] [PMID: 31512878]
[90]
Tian, W.F.; Wang, D.P.; Wang, S.F.; He, K.H.; Cao, X.P.; Li, Y. Visible-light photoredox-catalyzed iminyl radical formation by N-H cleavage with hydrogen release and its application in synthesis of isoquinolines. Org. Lett., 2018, 20(5), 1421-1425.
[http://dx.doi.org/10.1021/acs.orglett.8b00193] [PMID: 29451800]
[91]
Liu, W.D.; Lee, W.; Shu, H.; Xiao, C.; Xu, H.; Chen, X.; Houk, K.N.; Zhao, J. Diastereoselective radical aminoacylation of olefins through N-heterocyclic carbene catalysis. J. Am. Chem. Soc., 2022, 144(49), 22767-22777.
[http://dx.doi.org/10.1021/jacs.2c11209] [PMID: 36423331]
[92]
Dong, Y.X.; Zhang, C.L.; Gao, Z.H.; Ye, S. Iminoacylation of alkenes via photoredox N-heterocyclic carbene catalysis. Org. Lett., 2023, 25(5), 855-860.
[http://dx.doi.org/10.1021/acs.orglett.3c00006] [PMID: 36700625]

Rights & Permissions Print Cite
© 2025 Bentham Science Publishers | Privacy Policy