1198-37-4Relevant articles and documents
DMSO as a Switchable Alkylating Agent in Heteroarene C?H Functionalization
Garza-Sanchez, R. Aleyda,Patra, Tuhin,Tlahuext-Aca, Adrian,Strieth-Kalthoff, Felix,Glorius, Frank
, p. 10064 - 10068 (2018)
Herein, we report a novel strategy for the activation of DMSO to act as a versatile alkylating agent in heteroarene C?H functionalization. This direct, simple, and mild switch between methylation/trideuteromethylation and methylthiomethylation of heteroarenes was achieved under reagent-controlled photoredox catalysis conditions. The proposed mechanism is supported by both experimental and computational studies.
Molybdenum-Catalyzed Sustainable Friedl?nder Synthesis of Quinolines
Rubio-Presa, Rubén,Suárez-Pantiga, Samuel,Pedrosa, María R.,Sanz, Roberto
, p. 2216 - 2220 (2018)
Polysubstituted quinolines have been efficiently synthesized from nitroarenes and glycols, as reducing agents, under dioxomolybdenum(VI)-catalysis. Interestingly, the waste reduction byproduct is incorporated into the final heterocycle. This method repres
Late-stage functionalization of biologically active heterocycles through photoredox catalysis
DiRocco, Daniel A.,Dykstra, Kevin,Krska, Shane,Vachal, Petr,Conway, Donald V.,Tudge, Matthew
, p. 4802 - 4806 (2014)
The direct C-H functionalization of heterocycles has become an increasingly valuable tool in modern drug discovery. However, the introduction of small alkyl groups, such as methyl, by this method has not been realized in the context of complex molecule synthesis since existing methods rely on the use of strong oxidants and elevated temperatures to generate the requisite radical species. Herein, we report the use of stable organic peroxides activated by visible-light photoredox catalysis to achieve the direct methyl-, ethyl-, and cyclopropylation of a variety of biologically active heterocycles. The simple protocol, mild reaction conditions, and unique tolerability of this method make it an important tool for drug discovery.
β Arylaminoacrolein derivatives. II. Cyclodehydration of β arylaminoacrolein derivatives
Tamura,Yabe
, p. 2982 - 2986 (1974)
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A NEW GENERAL METHOD OF HOMOLYTIC ALKYLATION OF PROTONATED HETEROAROMATIC BASES BY CARBOXYLIC ACIDS AND IODOSOBENZENE DIACETATE.
Minisci, Francesco,Vismara, Elena,Fontana, Francesca,Barbosa, Maria Claudia Nogueira
, p. 4569 - 4572 (1989)
A new general, simple and mild procedure is reported in this communication, based on the photochemically induced decarboxylation of carboxylic acids by iodosobenzene diacetate to obtain the substitution of bases by nucleophilic alkyl radicals.
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Campbell,Schaffner
, p. 86,88 (1945)
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A General Organocatalytic System for Electron Donor-Acceptor Complex Photoactivation and Its Use in Radical Processes
De Pedro Beato, Eduardo,Melchiorre, Paolo,Spinnato, Davide,Zhou, Wei
supporting information, p. 12304 - 12314 (2021/08/20)
We report herein a modular class of organic catalysts that, acting as donors, can readily form photoactive electron donor-acceptor (EDA) complexes with a variety of radical precursors. Excitation with visible light generates open-shell intermediates under mild conditions, including nonstabilized carbon radicals and nitrogen-centered radicals. The modular nature of the commercially available xanthogenate and dithiocarbamate anion organocatalysts offers a versatile EDA complex catalytic platform for developing mechanistically distinct radical reactions, encompassing redox-neutral and net-reductive processes. Mechanistic investigations, by means of quantum yield determination, established that a closed catalytic cycle is operational for all of the developed radical processes, highlighting the ability of the organic catalysts to turn over and iteratively drive every catalytic cycle. We also demonstrate how the catalysts' stability and the method's high functional group tolerance could be advantageous for the direct radical functionalization of abundant functional groups, including aliphatic carboxylic acids and amines, and for applications in the late-stage elaboration of biorelevant compounds and enantioselective radical catalysis.
ZnMe2-Mediated, Direct Alkylation of Electron-Deficient N-Heteroarenes with 1,1-Diborylalkanes: Scope and Mechanism
Jo, Woohyun,Baek, Seung-Yeol,Hwang, Chiwon,Heo, Joon,Baik, Mu-Hyun,Cho, Seung Hwan
supporting information, p. 13235 - 13245 (2020/09/01)
The regioselective, direct alkylation of electron-deficient N-heteroarenes is, in principle, a powerful and efficient way of accessing alkylated N-heteroarenes that are important core structures of many biologically active compounds and pharmaceutical agents. Herein, we report a ZnMe2-promoted, direct C2- or C4-selective primary and secondary alkylation of pyridines and quinolines using 1,1-diborylalkanes as alkylation sources. While substituted pyridines and quinolines exclusively afford C2-alkylated products, simple pyridine delivers C4-alkylated pyridine with excellent regioselectivity. The reaction scope is remarkably broad, and a range of C2- or C4-alkylated electron-deficient N-heteroarenes are obtained in good yields. Experimental and computational mechanistic studies imply that ZnMe2 serves not only as an activator of 1,1-diborylalkanes to generate (α-borylalkyl)methylalkoxy zincate, which acts as a Lewis acid to bind to the nitrogen atom of the heterocycles and controls the regioselectivity, but also as an oxidant for rearomatizing the dihydro-N-heteroarene intermediates to release the product.
C2-Selective C-H methylation of heterocyclic N-oxides with sulfonium ylides
An, Won,Choi, Su Bin,Kim, Namhoon,Kwon, Na Yeon,Ghosh, Prithwish,Han, Sang Hoon,Mishra, Neeraj Kumar,Han, Sangil,Hong, Sungwoo,Kim, In Su
supporting information, p. 9004 - 9009 (2020/11/30)
A redox-neutral C2-selective methylation of heterocyclic N-oxides with sulfonium ylides is described herein. This report presents unprecedented findings for the utility of sulfonium ylides as the methylation source of N-heterocycles beyond the Corey-Chaykovsky reaction. Intriguingly, pyrrolidine plays a significant role in minimizing the reductive C2-methylation process. This method is characterized by its mild conditions, simplicity, and excellent site selectivity. The applicability of the developed protocol is showcased by the late-stage methylation and sequential transformations of complex drug molecules.
