Palladium-Catalyzed Direct C2-Arylation of Benzo[b]thiophenes with Electron-Rich Aryl Halides: Facile Access to Thienoacene Derivatives

Dedicated to Professor Victor Snieckus on the occasion of his 80^th birthday

Abstract

Direct coupling reaction of benzo[b]thiophene and electron-rich aryl bromides was achieved under Pd₂(dba)₃/SPhos catalysis in the presence of NaOt-Bu. The reaction system was applied for the installation of 2-(methylthio)phenyl group onto thiophene-fused polyaromatic molecules, demonstrating facile synthesis of precursors for thienoacene derivatives.

Key words

palladium catalyst - C–H functionalization - thiophene - poly­aromatic hydrocarbons - heteroacenes

• References and Notes


For selected reviews, see:
• 1a Sun Z. Ye Q. Chi C. Wu J. Chem. Soc. Rev. 2012; 41: 7857
• 1b Wang C. Dong H. Hu W. Liu Y. Zhu D. Chem. Rev. 2012; 112: 2208
• 1c Figueira-Duarte TM. Müllen K. Chem. Rev. 2011; 111: 7260
• 1d Pron A. Gawrys P. Zagorska M. Djuradoa D. Demadrillea R. Chem. Soc. Rev. 2010; 39: 2577
• 1e Anthony JE. Angew. Chem. Int. Ed. 2008; 47: 452
• 2 For a review, see: Takimiya K. Shinamura S. Osaka I. Miyazaki E. Adv. Mater. 2011; 23: 4347
• 3 Clar E. Polycyclic Hydrocarbons . Vol. 1. Academic Press; New York: 1964
• 4a Abe M. Mori T. Osaka I. Sugimoto K. Takimiya K. Chem. Mater. 2015; 27: 5049
• 4b Zou S. Wang Y. Gao J. Liu X. Hao W. Zhang H. Zhang H. Xie H. Yang C. Li H. Hu W. J. Mater. Chem. C 2014; 2: 10011
• 4c Chen L. Baumgarten M. Guo X. Li M. Marszalek T. Alsewailem FD. Pisula W. Muellen K. J. Mater. Chem. C 2014; 2: 3625
• 4d Guo X. Tsao HN. Gao P. Xia D. An C. Nazeeruddin MK. Baumgarten M. Grätzel M. Müllen K. RSC Adv. 2014; 4: 54130
• 4e Zheng T. Lu L. Jackson NE. Lou SJ. Chen LX. Yu L. Macromolecules 2014; 47: 6252
• 4f Li J. Qiao X. Xiong Y. Li H. Zhu D. Chem. Mater. 2014; 26: 5782
• 4g Yang YS. Yasuda T. Adachi C. Bull. Chem. Soc. Jpn. 2012; 85: 1186
• 4h Kim J. Yang C. Han A.-R. Oh JH. Seo JH. Chem. Mater. 2012; 24: 3464
• 5a Yue W. Ashraf RS. Nielsen CB. Collado-Fregoso E. Niazi MR. Yousaf SA. Kirkus M. Chen H.-Y. Amassian A. Durrant JR. McCulloch I. Adv. Mater. 2015; 27: 4702
• 5b Qi X. Zou S. Liu X. Hao W. Zhang H. Zang Z. Zhang H. Gao J. Hu W. New J. Chem. 2015; 39: 1045
• 5c Liu X. Qi X. Gao J. Zou S. Zhang H. Hao W. Zang Z. Li H. Hu W. Org. Electron. 2014; 15: 156
• 5d Son HJ. Lu L. Chen W. Xu T. Zheng T. Carsten B. Strzalka J. Darling SB. Chen LX. Yu L. Adv. Mater. 2013; 25: 838
• 5e Huang J. Luo H. Wang L. Guo Y. Zhang W. Chen H. Zhu M. Liu Y. Yu G. Org. Lett. 2012; 14: 3300
• 6 Ohta A. Akita Y. Ohkuna T. Chiba M. Fukunaga R. Miyafuji A. Nakata T. Tani N. Aoyagi Y. Heterocycles 1990; 31: 1951

For selected reviews, see:
• 7a Rossi R. Bellina F. Lessi M. Manzini C. Adv. Synth. Catal. 2014; 356: 17
• 7b Roger J. Gottumukkala AL. Doucet H. ChemCatChem 2010; 2: 20
• 7c Alberico D. Scott ME. Lautens M. Chem. Rev. 2007; 107: 174
• 7d Miura M. Satoh T. Hirano K. Bull. Chem. Soc. Jpn. 2014; 87: 751 ; and references cited therein
• 8a Ghosh D. Lee HM. Org. Lett. 2012; 14: 5534
• 8b Hu P. Zhang M. Jie X. Su W. Angew. Chem. Int. Ed. 2012; 51: 227
• 9 Pyrazole-directed C–H arylation of thiophene was reported: Reddy VP. Qiu R. Iwasaki T. Kambe N. Org. Lett. 2013; 15: 1290

Selected examples for the arylation of benzo[b]thiophene:
• 10a Chabert JF. D. Joucla L. David E. Lemaire M. Tetrahedron 2004; 60: 3221
• 10b David E. Perrin J. Pellet-Rostaing S. Chabert JF. D. Lemaire M. J. Org. Chem. 2005; 70: 3569
• 10c Liégault B. Lapointe D. Caron L. Vlassova A. Fagnou K. J. Org. Chem. 2009; 74: 1826
• 10d Tamba S. Okubo Y. Tanaka S. Monguchi D. Mori A. J. Org. Chem. 2010; 75: 6998
• 10e Zhao L. Bruneau C. Doucet H. Tetrahedron 2013; 69: 7082
• 11 General Procedure for Scheme 2 In a Schlenk tube, a mixture of benzo[b]thiophene (1, 1.0 mmol), aryl bromide 2 (1.5 mmol), NaOt-Bu (3.0 mmol), Pd₂(dba)₃ (0.005 mmol), and SPhos (0.01 mmol) in o-xylene (2.0 mL) was heated at 140 °C for specified reaction time under N₂. The resulting mixture was poured into H₂O and extracted with EtOAc three times. Combined organic layers were dried over Na₂SO₄ and concentrated in vacuo. The residue was subjected to silica gel chromatography and/or preparative gel permeation chromatography (GPC). 2-(4-Methylphenyl)benzo[b]thiophene (3b) Purified by column chromatography (eluent: hexane–EtOAc, 40:1) followed by GPC, 57% yield, orange solid, mp 56–57 °C. ¹H NMR (400 MHz, CDCl₃): δ = 2.43 (s, 3 H), 7.20 (dd, J = 1.5, 7.0 Hz, 1 H), 7.32–7.37 (m, 4 H), 7.46 (dd, J = 1.5, 5.5 Hz, 1 H), 7.46 (s, 1 H), 7.80 (dd, J = 1.5, 7.0 Hz, 1 H), 7.84 (dd, J = 1.5, 7.0 Hz, 1 H). ¹³C NMR (100 MHz, CDCl₃): δ = 16.29, 122.23, 123.88, 124.38, 124.46, 124.47, 124.91, 125.86, 128.96, 131.23, 133.32, 138.39, 140.09, 140.38, 141.67. HRMS (APCI): m/z [M + H]⁺ calcd for C₁₅H₁₃S₂: 257.0487; found: 257.0481. For other compounds, see the Supporting Information.
• 12 General Procedure for Table 2 In a Schlenk tube, a mixture of thiophene-based fused compound (0.5 mmol), aryl bromide 2 (1.5 mmol), NaOt-Bu (1.5 mmol), Pd₂(dba)₃ (0.005 mmol), and SPhos (0.01 mmol) in o-xylene (2.0 mL) was heated at 140 °C for 24 h. The resulting mixture was poured into H₂O and extracted with EtOAc three times. Combined organic layers were dried over Na₂SO₄ and concentrated in vacuo. The residue was subjected to silica gel chromatography and/or GPC. 2,5-Bis(2-methylthiophenyl)thieno[3,2-b]thiophene (5) Purified by GPC, 69% yield, white solid, mp 198–199 °C. ¹H NMR (400 MHz, CDCl₃): δ = 2.45 (s, 6 H), 7.20 (dt, J = 1.6, 7.3 Hz, 2 H), 7.32–7.35 (m, 4 H), 7.44 (s, 2 H), 7.44 (dd, J = 1.4, 7.4 Hz, 2 H). ¹³C NMR (100 MHz, CDCl₃):δ = 16.20, 119.93, 124.80, 125.70, 128.65, 131.01, 133.36, 138.21, 139.37, 142.62. HRMS (APCI): m/z [M + H]⁺ calcd for C₂₀H₁₇S₄: 385.0208; found: 385.0201. For other compounds, see the Supporting Information.