[en] Seven unsymmetrical imidazolium chlorides featuring a mesityl (Mes) or 2,6-diisopropylphenyl substituent (Dip) on one of their nitrogen atoms and a cycloalkyl group of variable size (cyclopentyl, cyclohexyl, 1-adamantanyl, cycloheptyl, cyclooctyl, or cyclododecyl) on the other one served to prepare a small library of novel palladium PEPPSI complexes with the generic formula [PdCl2(NHC)(Py)]. Three symmetrical compounds featuring the bulky yet flexible 1,3-dicyclododecylimidazol-2-ylidene and the archetypical IMes and IDip ligands were also synthesized. All the products were isolated in modest to satisfactory yields (15–85%) and fully characterized using 1H and 13C NMR spectroscopies. The molecular structures of five of them were determined using single crystal X-ray diffraction analysis, which revealed that, in most cases, the conformational freedom of the N-cycloalkyl moieties subsisted in the crystal phase. Topographic maps and %VBur parameters were computed to quantify the steric requirements of the uNHC ligands. The catalytic activity of the ten complexes was assessed in the Suzuki–Miyaura cross-coupling of phenylboronic acid and aryl halides. The reactions required only a low catalyst loading (0.05–0.25 mol%) and were carried out under mild aerobic conditions in a green, water-based solvent mixture. High yields of biphenyl derivatives were achieved with all the aryl bromides tested, irrespective of the presence of electron-donating or withdrawing substituents on their aromatic ring. When 4-chloro-acetophenone, a representative electron-poor aryl chloride served as substrate, all the complexes featuring cycloalkyl substituents on their NHC ligand became mostly inactive, whereas the IMes and IDip-based catalyst precursors maintained a high activity.
Disciplines :
Chemistry
Author, co-author :
Mazars, François ; Université de Liège - ULiège > Département de chimie (sciences) > Chimie organométallique et catalyse homogène ; Laboratory of Catalysis, MolSys Research Unit, Institut de Chimie Organique (B6a), Liège, Belgium
Zaragoza, Guillermo; Unidade de Difracción de Raios X, RIAIDT, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
Delaude, Lionel ; Université de Liège - ULiège > Département de chimie (sciences) > Chimie organométallique et catalyse homogène ; Laboratory of Catalysis, MolSys Research Unit, Institut de Chimie Organique (B6a), Liège, Belgium
Language :
English
Title :
Synthesis, characterization, and catalytic evaluation of palladium PEPPSI complexes bearing unsymmetrical NHC ligands in Suzuki–Miyaura reactions
King, A.O., Yasuda, N., Palladium-Catalyzed Cross-Coupling Reactions in the Synthesis of Pharmaceuticals. Top. Organomet. Chem. 6 (2004), 205–245, 10.1007/b94551.
Nicolaou, K.C., Bulger, P.G., Sarlah, D., Palladium-Catalyzed Cross-Coupling Reactions in Total Synthesis. Angew. Chem. Int. Ed. 44 (2005), 4442–4489, 10.1002/anie.200500368.
Chinchilla, R., Nájera, C., The Sonogashira Reaction: A Booming Methodology in Synthetic Organic Chemistry. Chem. Rev. 107 (2007), 874–922, 10.1021/cr050992x.
Torborg, C., Beller, M., Recent Applications of Palladium-Catalyzed Coupling Reactions in the Pharmaceutical, Agrochemical, and Fine Chemical Industries. Adv. Synth. Catal. 351 (2009), 3027–3043, 10.1002/adsc.200900587.
A. de Meijere, F. Diederich (Eds.) Metal-Catalyzed Cross-Coupling Reactions, Wiley-VCH, Weinheim, 2004, https://doi.org/10.1002/9783527619535.
Biffis, A., Centomo, P., Del Zotto, A., Zecca, M., Pd Metal Catalysts for Cross-Couplings and Related Reactions in the 21st Century: A Critical Review. Chem. Rev. 118 (2018), 2249–2295, 10.1021/acs.chemrev.7b00443.
Suzuki, A., Cross-Coupling Reactions Of Organoboranes: An Easy Way To Construct C-C Bonds (Nobel Lecture). Angew. Chem. Int. Ed. 50 (2011), 6722–6737, 10.1002/anie.201101379.
Negishi, E.-I., Magical Power of Transition Metals: Past, Present, and Future (Nobel Lecture). Angew. Chem. Int. Ed. 50 (2011), 6738–6764, 10.1002/anie.201101380.
Johansson Seechurn, C.C.C., Kitching, M.O., Colacot, T.J., Snieckus, V., Palladium-Catalyzed Cross-Coupling: A Historical Contextual Perspective to the 2010 Nobel Prize. Angew. Chem. Int. Ed. 51:2012 (2010), 5062–5085, 10.1002/anie.201107017.
Love, J.A., Morgan, J.P., Trnak, T.M., Grubbs, R.H., A practical and highly active ruthenium-based catalyst that effects the cross metathesis of acrylonitrile. Angew. Chem. Int. Ed. 41 (2002), 4035–4037, 10.1002/1521-3773(20021104)41:21%3C4035::AID-ANIE4035%3E3.0.CO;2-I.
O'Brien, C.J., Kantchev, E.A.B., Valente, C., Hadei, N., Chass, G.A., Lough, A., Hopkinson, A.C., Organ, M.G., Easily prepared air- and moisture-stable Pd-NHC (NHC = N-heterocyclic carbene) complexes: A reliable, user-friendly, highly active palladium precatalyst for the Suzuki-Miyaura reaction. Chem. Eur. J. 12 (2006), 4743–4748, 10.1002/chem.200600251.
Nasielski, J., Hadei, N., Achonduh, G., Kantchev, E.A.B., O'Brien, C.J., Lough, A., Organ, M.G., Structure-Activity Relationship Analysis of Pd–PEPPSI Complexes in Cross-Couplings: A Close Inspection of the Catalytic Cycle and the Precatalyst Activation Model. Chem. Eur. J. 16 (2010), 10844–10853, 10.1002/chem.201000138.
Kantchev, E.A.B., O'Brien, C.J., Organ, M.G., Palladium Complexes of N-Heterocyclic Carbenes as Catalysts for Cross-Coupling Reactions—A Synthetic Chemist's Perspective. Angew. Chem. Int. Ed. 46 (2007), 2768–2813, 10.1002/anie.200601663.
Valente, C., Çalimsiz, S., Hoi, K.H., Mallik, D., Sayah, M., Organ, M.G., The development of bulky palladium NHC complexes for the most-challenging cross-coupling reactions. Angew. Chem. Int. Ed. 51 (2012), 3314–3332, 10.1002/anie.201106131.
Organ, M.G., Çalimsiz, S., Sayah, M., Hoi, K.H., Lough, A.J., Pd-PEPPSI-IPent: An Active, Sterically Demanding Cross-Coupling Catalyst and Its Application in the Synthesis of Tetra-Ortho-Substituted Biaryls. Angew. Chem. Int. Ed. 48 (2009), 2383–2387, 10.1002/anie.200805661.
Tornatzky, J., Kannenberg, A., Blechert, S., New catalysts with unsymmetrical N-heterocyclic carbene ligands. Dalton Trans. 41 (2012), 8215–8225, 10.1039/c2dt30256j.
Kaloglu, N., Özdemir, I., PEPPSI-Pd-NHC catalyzed Suzuki-Miyaura cross-coupling reactions in aqueous media. Tetrahedron 75 (2019), 2306–2313, 10.1016/j.tet.2019.02.062.
Song, A.-X., Zeng, X.-X., Ma, B.-B., Xu, C., Liu, F.-S., Direct (Hetero)arylation of Heteroarenes Catalyzed by Unsymmetrical Pd-PEPPSI-NHC Complexes under Mild Conditions. Organometallics 39 (2020), 3524–3534, 10.1021/acs.organomet.0c00494.
Slimani, I., Mansour, L., Özdemir, İ., Gürbüz, N., Hamdi, N., Synthesis, characterization and catalytic activity of PEPPSI-type palladium–NHC complexes. Inorg. Chim. Acta, 515, 2021, 120043, 10.1016/j.ica.2020.120043.
Nawaz, Z., Gürbüz, N., Naveed Zafar, M., Nawaz Tahir, M., Ashfaq, M., Karci, H., Özdemir, İ., Direct arylation (hetero-coupling) of heteroarenes via unsymmetrical palladium-PEPPSI-NHC type complexes. Polyhedron, 208, 2021, 115412.
Korukçu, M.Ç., Can, S., Pd–PEPPSI type complexes bearing unsymmetrical NHC ligand with phenyl-substituted backbone: Highly efficient catalysts for Heck-Mizoroki and Suzuki-Miyaura cross-coupling reactions. Appl. Organomet. Chem., 37, 2023, e7057.
Teci, M., Brenner, E., Matt, D., Toupet, L., N-Heterocyclic Carbenes Functioning as Monoligating Clamps. Eur. J. Inorg. Chem. 2013:16 (2013), 2841–2848.
Queval, P., Jahier, C., Rouen, M., Artur, I., Legeay, J.-C., Falivene, L., Toupet, L., Crévisy, C., Cavallo, L., Baslé, O., Mauduit, M., Multicomponent Synthesis of Unsymmetrical Unsaturated N-Heterocyclic Carbene Precursors and Their Related Transition-Metal Complexes. Angew. Chem. Int. Ed. 52 (2013), 14103–14107, 10.1002/anie.201308873.
Tarrieu, R., Dumas, A., Thongpaen, J., Vives, T., Roisnel, T., Dorcet, V., Crévisy, C., Baslé, O., Mauduit, M., Readily Accessible Unsymmetrical Unsaturated 2,6-Diisopropylphenyl N-Heterocyclic Carbene Ligands. Applications in Enantioselective Catalysis. J. Org. Chem. 82 (2017), 1880–1887, 10.1021/acs.joc.6b02888.
Hans, M., Lorkowski, J., Demonceau, A., Delaude, L., Efficient synthetic protocols for the preparation of common N-heterocyclic carbene precursors. Beilstein J. Org. Chem. 11 (2015), 2318–2325, 10.3762/bjoc.11.252.
Jadhav, B.D., Pardeshi, S.K., Synthesis and catalytic application of Pd complex catalysts: Atom-efficient cross-coupling of triarylbismuthines with haloarenes and acid chlorides under mild conditions. Appl. Organomet. Chem., 31(4), 2017, e3591.
Guillet, S.G., Voloshkin, V.A., Saab, M., Beliš, M., Van Hecke, K., Nahra, F., Nolan, S.P., Understanding existing and designing novel synthetic routes to Pd-PEPPSI-NHC and Pd-PEPPSI-PR3 pre-catalysts. Chem. Commun. 56 (2020), 5953–5956, 10.1039/d0cc02262d.
Rahman, M.M., Zhang, J., Zhao, Q., Feliciano, J., Bisz, E., Dziuk, B., Lalancette, R., Szostak, R., Szostak, M., Pd–PEPPSI N-Heterocyclic Carbene Complexes from Caffeine: Application in Suzuki, Heck, and Sonogashira Reactions. Organometallics 41 (2022), 2281–2290, 10.1021/acs.organomet.2c00262.
Janiak, C., A critical account on π–π stacking in metal complexes with aromatic nitrogen-containing ligands. J. Chem. Soc., Dalton Trans., 2000, 3885–3896, 10.1039/b003010o.
Altenhoff, G., Goddard, R., Lehmann, C.W., Glorius, F., An N-Heterocyclic Carbene Ligand with Flexible Steric Bulk Allows Suzuki Cross-Coupling of Sterically Hindered Aryl Chlorides at Room Temperature. Angew. Chem. Int. Ed. 42 (2003), 3690–3693, 10.1002/anie.200351325.
Altenhoff, G., Goddard, R., Lehmann, C.W., Glorius, F., Sterically Demanding, Bioxazoline-Derived N-Heterocyclic Carbene Ligands with Restricted Flexibility for Catalysis. J. Am. Chem. Soc. 126 (2021), 15195–15201, 10.1021/ja045349r.
Poater, A., Ragone, F., Mariz, R., Dorta, R., Cavallo, L., Comparing the Enantioselective Power of Steric and Electrostatic Effects in Transition-Metal-Catalyzed Asymmetric Synthesis. Chem. Eur. J. 16 (2010), 14348–14353, 10.1002/chem.201001938.
Falivene, L., Cao, Z., Petta, A., Serra, L., Poater, A., Oliva, R., Scarano, V., Cavallo, L., Towards the online computer-aided design of catalytic pockets. Nature Chem. 11:10 (2019), 872–879.
Poater, A., Ragone, F., Giudice, S., Costabile, C., Dorta, R., Nolan, S.P., Cavallo, L., Thermodynamics of N-Heterocyclic Carbene Dimerization: The Balance of Sterics and Electronics. Organometallics 27 (2008), 2679–2681, 10.1021/om8001119.
Clavier, H., Nolan, S.P., Percent buried volume for phosphine and N-heterocyclic carbene ligands: steric properties in organometallic chemistry. Chem. Commun. 46 (2010), 841–861, 10.1039/b922984a.
Mazars, F., Zaragoza, G., Delaude, L., Caffeine and theophylline as sustainable, biosourced NHC ligand precursors for efficient palladium-catalyzed Suzuki-Miyaura cross-coupling reactions. J. Organomet. Chem., 978, 2022, 122489, 10.1016/j.jorganchem.2022.122489.
Capello, C., Fischer, U., Hungerbühler, K., What is a green solvent? A comprehensive framework for the environmental assessment of solvents. Green Chem. 9 (2007), 927–934, 10.1039/B617536H.
Bruker, APEX3, Madison, WI, USA, 2005.
Clark, R.C., Reid, J.S., The Analytical Calculation of Absorption in Multifaceted Crystals, Acta Crystallogr. Sect. A: Fundam. Crystallogr. 51 (1995), 887–897, 10.1107/s0108767395007367.
Burla, M.C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G.L., De Caro, L., Giacovazzo, C., Polidori, G., Spagna, R., SIR2004: An Improved Tool for Crystal Structure Determination and Refinement. J. Appl. Crystallogr. 38 (2005), 381–388, 10.1107/s002188980403225x.
G.M. Sheldrick, SHELX-97 (SHELXS 97 and SHELXL 97), Programs for Crystal Structure Analyses, University of Göttingen, Göttingen (Germany), 1998.
G.M. Sheldrick, SADABS, Programs for Scaling and Correction of Area Detection Data, University of Göttingen, Göttingen (Germany), 1996.