Synthesis, Inhaltsverzeichnis Synthesis 2023; 55(21): 3526-3534DOI: 10.1055/s-0041-1738433 special topic C–H Bond Functionalization of Heterocycles Palladium-Catalyzed C7–H (Hetero)arylation of Pyrazolo[1,5-a]pyrazines with Heteroarenes and Aryl Iodides with the Assistance of Silver Salts Thanh V. Q. Nguyen ∗ a Medicinal Chemistry, Research and Early Development, Respiratory and Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden , Armand Levoin a Medicinal Chemistry, Research and Early Development, Respiratory and Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden b University of Strasbourg, 4 Rue Blaise Pascal, 67081 Strasbourg, France , Lorenzo Poli a Medicinal Chemistry, Research and Early Development, Respiratory and Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden b University of Strasbourg, 4 Rue Blaise Pascal, 67081 Strasbourg, France› InstitutsangabenArtikel empfehlen Abstract Artikel einzeln kaufen Alle Artikel dieser Rubrik Abstract Pyrazolo[1,5-a]pyrazines coupled with heteroarenes and aryl iodides selectively at the C7 position to afford a broad library of bi(hetero)aryl structures under ligand-free palladium-catalyzed conditions. The key to the success of the reaction is the use of silver salts as the oxidant or the base, allowing the regioselective C–H bond functionalization to occur under relatively mild conditions. Key words Key wordsC–H bond functionalization - fused-ring systems - heteroarenes - homogeneous catalysis - synthetic methods Volltext Referenzen References 1a Gerstenberger BS, Ambler C, Arnold EP, Banker ME, Brown MF, Clark JD, Dermenci A, Dowty ME, Fensome A, Fish S, Hayward MM, Hegen M, Hollingshead BD, Knafels JD, Lin DW, Lin TH, Owen DR, Saiah E, Sharma R, Vajdos FF, Xing L, Yang X, Yang X, Wright SW. J. Med. Chem. 2020; 63: 13561 1b Martínez González S, Hernández AI, Álvarez RM, Rodríguez A, Ramos-Lima F, Bischoff JR, Albarrán MI, Cebriá A, Hernández-Encinas E, García-Arocha J, Cebrián D, Blanco-Aparicio C, Pastor J. Bioorg. Med. Chem. Lett. 2017; 27: 4794 1c Ratni H, Karp GM, Weetall M, Naryshkin NA, Paushkin SV, Chen KS, McCarthy KD, Qi H, Turpoff A, Woll MG, Zhang X, Zhang N, Yang T, Dakka A, Vazirani P, Zhao X, Pinard E, Green L, David-Pierson P, Tuerck D, Poirier A, Muster W, Kirchner S, Mueller L, Gerlach I, Metzger F. J. Med. Chem. 2016; 59: 6086 2a Bozhanov VI, Bohdan DP, Borysov OV, Silin AV, Zaremba OV, Avramenko MM, Volochnyuk DM, Ryabukhin SV, Gavrilenko KS. ChemistrySelect 2022; 7: e202104287 2b Barsanti PA, Aversa RJ, Jin X, Pan Y, Lu Y, Elling R, Jain R, Knapp M, Lan J, Lin X, Rudewicz P, Sim J, Taricani L, Thomas G, Xiao L, Yue Q. ACS Med. Chem. Lett. 2015; 6: 37 3a Lindsay-Scott PJ, Charlesworth NG, Grozavu A. J. Org. Chem. 2017; 82: 11295 3b Mousseau JJ, Bull JA, Ladd CL, Fortier A, Sustac Roman D, Charette AB. J. Org. Chem. 2011; 76: 8243 Several reviews on C–H arylation, see: 4a Caro-Diaz EJ. E, Urbano M, Buzard DJ, Jones RM. Bioorg. Med. Chem. Lett. 2016; 26: 5378 4b Yamaguchi J, Yamaguchi AD, Itami K. Angew. Chem. Int. Ed. 2012; 51: 8960 4c Yuan S, Chang J, Yu B. Top. Curr. Chem. 2020; 378: 23 4d Albano G, Punzi A, Capozzi MA. M, Farinola GM. Green Chem. 2022; 24: 1809 4e Hagui W, Doucet H, Soulé J.-F. Chem 2019; 5: 2006 4f Li B, Ali AI. M, Ge H. Chem 2020; 6: 2591 ; and references therein 5 Choy PY, Wong SM, Kapdi A, Kwong FY. Org. Chem. Front. 2018; 5: 288 6a Faarasse S, El Brahmi N, Guillaumet G, El Kazzouli S. Molecules 2021; 26: 5763 6b Aziz J, Piguel S. Synthesis 2017; 49: 4562 7a Bedford RB, Durrant SJ, Montgomery M. Angew. Chem. Int. Ed. 2015; 54: 8787 7b Oh KH, Kim SM, Lee MJ, Park JK. Adv. Synth. Catal. 2015; 357: 3927 7c Wu H.-C, Chu J.-H, Li C.-W, Hwang L.-C, Wu M.-J. Organometallics 2016; 35: 288 8 Nguyen TV. Q, Poli L, Garrison AT. Chem. Commun. 2022; 58: 827 9 Cs2CO3 could facilitate the H/D exchange of (hetero)arenes and DMSO-d 6 in the absence of D2O, see: Salamanca V, Albéniz AC. Eur. J. Org. Chem. 2020; 3206 Formation of (hetero)arene-Ag complex was generally proposed when silver salt was indispensable for C–H bond cleavage (experimentally confirmed when Ag salt was crucial for H/D exchange), for example, see: 10a Zhang H.-H, Wang C.-X, Sheng F.-F, Liu K.-H, Gu J.-G, Shen K, Sun Z.-Y, Hong K. Synthesis 2022; 54: 4025 10b Tlahuext-Aca A, Lee SY, Sakamoto S, Hartwig JF. ACS Catal. 2021; 11: 1430 10c Liu KH, Hu GQ, Wang CX, Sheng FF, Bai JW, Gu JG, Zhang HH. Org. Lett. 2021; 23: 5626 Silver cation could act as iodide scavenger to remove iodide from palladium, see: 11a Arroniz C, Denis JG, Ironmonger A, Rassias G, Larrosa I. Chem. Sci. 2014; 5: 3509 11b Srinivasan R, Dey A, Nagarajan NS, Kumaran RS, Gandhi T, Maiti D. Chem. Commun. 2017; 53: 11709 11c Joshi A, Semwal R, Suresh E, Adimurthy S. Chem. Commun. 2019; 55: 10888 Zusatzmaterial Zusatzmaterial Supporting Information
