Categories: Synthesis of N-Heterocycles >
Synthesis of 1,2,3-triazoles and benzotriazoles
The synthesis of 1-monosubstituted aryl 1,2,3-triazoles was achieved in good yields using calcium carbide as a source of acetylene. The copper-catalyzed 1,3-dipolar cycloaddition reactions were carried out without nitrogen protection and in a MeCN-H2O mixture.
Y. Jiang, C. Kuang, Q. Yang, Synlett, 2009, 3163-3166.
A Pd-catalyzed synthesis of 1H-triazoles from alkenyl halides and sodium azide represents a completely new reactivity pattern in the context of Pd chemistry.
J. Barluenga, C. Valdés, G. Beltrán, M. Escribano, F. Aznar, Angew. Chem. Int. Ed., 2006, 45, 6893-6896.
A tandem catalysis protocol based on decarboxylative coupling of alkynoic acids and 1,3-dipolar cycloaddition of azides avoids usage of gaseous or highly volatile terminal alkynes, reduces handling of potentially unstable and explosive azides to a minimum, and furnishes various functionalized 1,2,3-triazoles in excellent yields and a very good purity without the need for additional purification.
A. Kolarovič, M. Schnürch, M. D. Mihovilovic, J. Org. Chem., 2011, 76, 2613-2618.
Self-assembly of copper sulfate and a poly(imidazole-acrylamide) amphiphile provides a highly active, reusable, globular, solid-phase catalyst for click chemistry. The insoluble amphiphilic polymeric imidazole Cu catalyst drove the cycloaddition of various of alkynes and organic azides at very low catalyst loadings and can be readily reused without loss of activity to give the corresponding triazoles quantitatively.
Y. M. A. Yamada, S. M. Sarkar, Y. Uozumi, J. Am. Chem. Soc., 2012, 134, 9285-9286.
4-Aryl-1H-1,2,3-triazoles were synthesized from anti-3-aryl-2,3-dibromopropanoic acids and sodium azide by using inexpensive copper(I) iodide as the catalyst in the presence of cesium carbonate as base and DMSO as solvent.
Y. Jiang, C. Kuang, Q. Yang, Synthesis, 2010, 4256-4260.
4-Aryl-1H-1,2,3-triazoles were synthesized from anti-3-aryl-2,3-dibromopropanoic acids and sodium azide by a one-pot method using N,N-dimethylformamide as solvent in the presence of Pd2(dba)3 and Xantphos.
W. Zhang, C. Kuang, Q. Yang, Synthesis, 2010, 283-287.
1-Substituted-1,2,3-triazoles were conveniently synthesized from the corresponding aromatic and aliphatic azides in the presence of acetylene gas using mild, copper(I)-catalyzed ‘click chemistry'.
L.-Y. Wu, Y.-X. Xie, Z.-S. Chen, Y.-N. Niu, Y.-M. Liang, Synlett, 2009, 1453-1456.
A true Click catalytic system is based on commercially available [CuBr(PPh3)3]. This system is active at room temperature, with catalyst loadings of 0.5 mol % or less, in the absence of any additive, and it does not require any purification step to isolate pure triazoles.
S. Lal, S. Díez-González, J. Org. Chem., 2011, 76, 2367-2373.
A well-defined copper(I) isonitrile complex is an efficient, heterogeneous catalyst for azide-alkyne 1,3-dipolar cycloadditions and three-component reactions of halides, sodium azide and alkynes to form 1,4-disubstituted 1,2,3-triazoles in high yields under mild conditions in water. The complex can be recycled for at least five runs without significant loss of activity by simple precipitation and filtration.
M. Liu, O. Reiser, Org. Lett., 2011, 13, 1102-1105.
Cycloadditions of copper(I) acetylides to azides and nitrile oxides provide ready access to 1,4-disubstituted 1,2,3-triazoles and 3,4-disubstituted isoxazoles, respectively. The process is highly reliable and exhibits an unusually wide scope with respect to both components. Computational studies revealed a nonconcerted mechanism involving unprecedented metallacycle intermediates.
F. Himo, T. Lovell, R. Hilgraf, V. V. Rostovtsev, L. Noodleman, K. B. Sharpless, V. V. Fokin, J. Am. Chem. Soc., 2005, 127, 210-216.
A mild, zinc-mediated method for regioselective formation of 1,5-substituted 1,2,3-triazoles from a wide range of azides and alkynes works at room temperature. Additionally, the triazole 4-position can be further functionalized by reaction of the intermediate aryl-zinc with various electrophiles to accommodate a diverse three-component coupling strategy.
C. D. Smith, M. F. Greaney, Org. Lett., 2013, 15, 4826-4829.
1,5-Diarylsubstituted 1,2,3-triazoles are formed in high yield from aryl azides and terminal alkynes in DMSO in the presence of a catalytic amount of tetraalkylammonium hydroxide or t-BuOK for base-labile substrates. The reaction is experimentally simple, does not require a transition-metal catalyst, and is not sensitive to atmospheric oxygen and moisture.
S. W. Kwok, J. R. Fotsing, R. J. Fraser, V. O. Rodinov, V. V. Fokin, Org. Lett., 2010, 12, 4217-4219.
The use of t-BuOK in wet DMF as desilylating reagent in a cycloaddition reaction of aromatic azides and trimethylsilyl alkynes generated 1,5-disubstituted 1,2,3-triazoles regioselectively in good yields at ambient temperature.
L. Wu, X. Chen, M. Tang, X. Song, G. Chen, X. Song, Q. Lin, Synlett, 2012, 23, 1529-1533.
In the presence Cp*RuCl(PPh3)2 or Cp*RuCl(COD) as catalyst, primary and secondary azides react with a broad range of terminal alkynes containing a range of functionalities selectively producing 1,5-disubstituted 1,2,3-triazoles. Both complexes also promote the cycloaddition reactions of organic azides with internal alkynes, providing access to fully-substituted 1,2,3-triazoles.
B. C. Boren, S. Narayan, L. K. Rasmussen, L. Zhang, H. Zhao, Z. Lin, G. Jia, V. V. Fokin, J. Am. Chem. Soc., 2008, 130, 8923-8930.
In the presence of inexpensive copper (I) iodide as the catalyst, a series of 1,4-disubstituted 1,2,3-triazoles were synthesized in a one-pot process from anti-3-aryl-2,3-dibromopropanoic acids and organic azides in dimethyl sulfoxide.
X. Chen, Y. Yang, C. Kuang, Q. Yang, Synthesis, 2011, 2907-2912.
A copper(I)-catalyzed three-component reaction of amines, propargyl halides and azides forms 1-substituted-1H-1,2,3-triazol-4-ylmethyl)-dialkylamines in water. Synthetic advantages are high atom economy, low environmental impact, atmospheric oxygen, wide substrate scope, mild reaction condition and good yields.
Z.-Y. Yan, Y.-B. Zhao, M.-J. Fan, W.-M. Liu, Y.-M. Liang, Tetrahedron, 2005, 61, 9331-9337.
A method for the regiospecific synthesis of 1,4,5-trisubstituted-1,2,3-triazole catalyzed by copper(I) iodide was developed. This is the first example of a regiospecific synthesis of 5-iodo-1,4-disubstituted-1,2,3-triazole, which can be further elaborated to a range of 1,4,5-trisubstituted-1,2,3-triazole derivatives.
Y.-M. Wu, J. Deng, Y. L. Li, Q.-Y. Chen, Synthesis, 2005, 1314-1318.
Inexpensive copper catalysts enabled modular one-pot multicomponent syntheses of fully decorated triazoles through a sustainable “click” reaction/direct arylation sequence.
L. Ackermann, H. K. Potukuchi, D. Landsberg, R. Vicente, Org. Lett., 2008, 10, 3081-3084.
Microwave irradiation significantly enhances the rate of formation of 1,4-disubstituted 1,2,3-triazoles from alkynes and in situ generated azides. Azides are derived from an efficient one-pot azidation of anilines with the reagent combination t-BuONO and TMSN3.
A. D. Moorhouse, J. E. Moses, Synlett, 2008, 2089-2092.
A reliable and operationally simple one-pot reaction for a one-carbon homologation of various aldehydes followed by Cu-catalyzed azide-alkyne click chemistry gives 1,4-disubstituted 1,2,3-triazoles in good yields without the need for isolation of the alkyne intermediates.
D. Luvino, C. Amalric, M. Smietana, J.-J. Vasseur, Synlett, 2007, 3037-3041.
1,2,3-Triazoles were prepared in good to modest yields by cycloaddition of alkyl azides onto enol ethers under solventless conditions. The reaction can access ring-fused triazoles that are unavailable by azide-alkyne cycloadditions and is easily scalable. The 1,2,3-triazole products bear functionality that may be readily derivatized.
D. R. Rogue, J. L. Neill, J. W. Antoon, E. P. Stevens, Synthesis, 2005, 2497-2502.
Triazoles have been synthesized via a three-component coupling reaction of unactivated terminal alkynes, allyl carbonate, and trimethylsiyl azide under Pd(0)-Cu(I) bimetallic catalysis. The deallylation of the resulting allyltriazoles is described.
S. Kamijo, T. Jin, Z. Huo, Y. Yamamoto, J. Am. Chem. Soc., 2003, 125, 7786-7787.
Reaction of 4-bromo-NH-1,2,3-triazoles with alkyl halides in the presence of K2CO3 in DMF produced the corresponding 2-substituted 4-bromo-1,2,3-triazoles in a regioselective process. Subsequent Suzuki cross-coupling reaction provided an efficient synthesis of 2,4,5-trisubstituted triazoles, whereas hydrogenation furnished an efficient synthesis of 2,4-disubstituted triazoles.
X.-j. Wang, K. Sidhu, L. Zhang, S. Campbell, N. Haddad, D. C. Reeves, D. Krishnamurthy, C. H. Senanayake, Org. Lett., 2009, 11, 5460-5493.
A palladium-catalyzed and ultrasonic promoted Sonogashira coupling/1,3-dipolar cycloaddition of acid chlorides, terminal acetylenes, and sodium azide in one pot enables an efficient synthesis of 4,5-disubstituted-1,2,3-(NH)-triazoles in excellent yields.
J. Li, D. Wang, Y. Zhang, J. Li, B. Chen, Org. Lett., 2009, 11, 3024-3027.
TBAF-catalyzed [3 + 2] cycloadditions of 2-aryl-1-cyano- or 2-aryl-1-carbethoxy-1-nitroethenes with TMSN3 under solvent free conditions allow the preparation of 4-aryl-5-cyano- or 4-aryl-5-carbethoxy-1H-1,2,3-triazoles under mild reaction conditions with good to excellent yields.
D. Amantini, F. Fringuelli, O. Piermatti, F. Pizzo, E. Zunino, L. Vaccaro, J. Org. Chem., 2005, 70, 6526-6529.
Triazole-based monophosphine ligands have been prepared via efficient cycloadditions. Palladium complexes derived from these ligands are highly active catalysts for Suzuki-Miyaura coupling and amination reactions of aryl chlorides.
D. Liu, W. Gao, Q. Dai, X. Zhang, Org. Lett., 2005, 7, 4907-4910.
A highly efficient method for the synthesis of multisubstituted 1,2,3-triazoles via a direct Pd-catalyzed C-5 arylation has been developed.
S. Chuprakov, N. Chernyak, A. S. Dudnik, V. Gevorgyan, Org. Lett., 2007, 9, 2333-2336.
The use of nontoxic polyethylene glycol (PEG) as solvent and MesCO2H as cocatalyst enabled user-friendly palladium(0)-catalyzed C-H bond functionalizations under air in the absence of phosphine ligands. Direct arylations of 1,2,3-triazoles gave substituted triazoles in good yields. Recycling of the catalytic system led to a slight decrease of activity.
L. Ackermann, R. Vicente, Org. Lett., 2009, 11, 4922-4925.
Conditions for the palladium-catalyzed direct arylation of a wide range of heterocycles with aryl bromides employ a stoichiometric ratio of both coupling partners, as well as a substoichiometric quantity of pivalic acid, which results in significantly faster reactions. An evaluation of the influence of the nature of the aryl halide has also been carried out.
B. Liégault, D. Lapointe, L. Caron, A. Vlassova, K. Fagnou, J. Org. Chem., 2009, 74, 1826-1834.
A [3 + 2] cycloaddition of azides to benzynes affords a rapid and easy entry to a variety of substituted, functionalized benzotriazoles under mild conditions.
F. Shi, J. P. Waldo, Y. Chen, R. C. Larock, Org. Lett., 2008, 10, 2409-2412.
A 1,7-palladium migration-cyclization-dealkylation sequence for the regioselective synthesis of benzotriazoles proceed in excellent yields with high regioselectivities. The mechanism of the reaction has also been investigated.
J. Zhou, J. He, B. Wang, W. Yang, H. Ren, J. Am. Chem. Soc., 2011, 133, 6868-6870.
C-H activation of aryl triazene compounds followed by intramolecular amination in the presence of a catalytic amount of Pd(OAc)2 provides 1-aryl-1H-benzotriazoles at moderate temperature.
R. K. Kumar, M. A. Ali, T. Punniyamurthy, Org. Lett., 2011, 13, 2102-2105.