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Synlett 2006(15): 2423-2426  
DOI: 10.1055/s-2006-950426
LETTER
© Georg Thieme Verlag Stuttgart · New York

Palladium-Catalyzed C-H Arylation of Thieno[2,3-b]thiophene: An Approach to Novel 2,5-Diaryl/Heteroaryl Thieno[2,3-b]thiophenes

Sabir H. Mashraqui*, Mohamed Ashraf, Shailesh G. Ghadigaonkar
Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz-E, Mumbai 400098, India
Fax: +91(22)26528547; e-Mail: sh_mashraqui@yahoo.com;
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Publication History

Received 27 June 2006
Publication Date:
08 September 2006 (online)

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Abstract

Direct C-H arylation of thieno[2,3-b]thiophene is reported under Pd(OAc)2/n-Bu4NBr catalysis and provides rapid entry into the first examples of 2,5-diaryl thienothiophenes. The reaction works well with either electron-deficient or electron-rich halo-arenes, giving satisfactory yields of diarylation products. Novel push-pull thienothiophenes bearing electron-deficient aryl groups (λmax 318-373 nm and λcut-off 430 nm) are potentially interesting for their photonic properties.

Key words

palladium catalysis - C-H arylation - thieno[2,3-b]thiophene - 2,5-diarylthieno[2,3-b]thiophenes - UV-visible

    References and Notes

  • 1 Raimundo J.-M. Blanchard P. Gallego-Planas N. Mercier N. Ledoux-Rak I. Hierle R. Roncali J. J. Org. Chem.  2002,  67:  205 
    CrossrefGoogle Scholar
  • 2a Greenwald Y. Poplawski J. Ehrenfreund E. Speiser S. Synth. Met.  1997,  85:  1353 
    CrossrefGoogle Scholar
  • 2b Semenikhin OA. Ovsyannikava EV. Alpatova NM. Rotenberg ZA. Kazarinov VE. J. Electroanal. Chem.  1999,  463:  190 
    CrossrefGoogle Scholar
  • 3 Huang B. Li J. Jiang Z. Qin J. Yu G. Liu Y. Macromolecules  2005,  38:  6915 
    CrossrefGoogle Scholar
  • 4 Mitschke U. Osteritz EM. Debaerdemaeker T. Sokolowski M. Bauerle P. Chem. Eur. J.  1998,  4:  2211 
    CrossrefGoogle Scholar
  • 5a Blenkle M. Boldt P. Bräuchle C. Grahn W. Ledoux I. Nerenz H. Stadler S. Wichern J. Zyss J. J. Chem. Soc., Perkin Trans. 2  1996,  1377 
    Google Scholar
  • 5b Boldt P. Blenkle M. Cabrera I. Lupo W. Hickel W. Nonlinear Opt.  1994,  8:  173 
    Google Scholar
  • 6 Albota M. Betjonne D. Bredas J.-J. Ehrlich JE. Fu J.-Y. Heikeal AA. Hess SE. Kogej T. Levin MD. Marder SR. McCord-Maughon D. Perry JW. Rockel H. Rumi M. Subramaniam G. Webb WW. Wu X.-L. Xu C. Science  1998,  281:  1653 
    CrossrefGoogle Scholar
  • 7 Prim D. Kirsch G. J. Chem. Soc., Perkin Trans. 1  1994,  18:  2603 
    Google Scholar
  • 8 For a solitary report describing introduction of thiophene at the C2,C5 positions of thieno[2,3-b]thiophene by Stille’s protocol, see: Heeney M. Bailey C. Genevicius K. Shukunov M. Sparrowe D. Tierney S. McCulloch I. J. Am. Chem. Soc.  2005,  127:  1078 
    CrossrefGoogle Scholar
  • 9a Mashraqui SH. Hariharasubramanian H. Kumar S. Synthesis  1999,  2030 
    Google Scholar
  • 9b Mohareb RM. Sherif SM. Habashi A. Abdel-Sayed NI. Osman SS. Collect. Czech. Chem. Commun.  1995,  60:  1578 
    Google Scholar
  • 9c El-Saghier AMM. Bull. Chem. Soc. Jpn.  1993,  66:  2011 
    Google Scholar
  • 9d Dejong RL. Brandsma L. Synth. Commun.  1991,  21:  145 
    Google Scholar
  • 9e Junjappa H. Ila H. Asokan CV. Tetrahedron  1990,  46:  5423 
    Google Scholar
  • 9f Dalgaard L. Jensen L. Lawesson SO. Tetrahedron  1974,  30:  93 
    Google Scholar
  • 9g Abdel-Ghany H. Khodairy A. Phosphorous, Sulfur Silicon Relat. Elem.  2000,  166:  45 
    Google Scholar
  • 10a 3,4-Diaryl/heteroaryl thieno[2,3-b]thiophenes are well known, see: Mashraqui SH. Ashraf M. Harini H. Kellogg RM. Meetsma A. J. Mol. Struct.  2004,  689:  107 
    CrossrefGoogle Scholar
  • 10b Mashraqui SH. Sangvikar Y. Ashraf M. Kumar S. Daub ETH. Tetrahedron  2005,  61:  3507 
    CrossrefGoogle Scholar
  • 11a Hassan J. Sevignon M. Gozzi C. Schulz E. Lemaire M. Chem. Rev.  2002,  102:  1359 
    Google Scholar
  • 11b Littke AF. Fu GC. Angew. Chem. Int. Ed.  2002,  41:  4176 
    Google Scholar
  • 11c Espinet P. Echavarren AM. Angew. Chem. Int. Ed.  2004,  43:  4704 
    Google Scholar
  • 11d Fang Y.-Q. Hanan GS. Synlett  2003,  852 
    Google Scholar
  • 11e Wallace DJ. Chen C.-Y. Tetrahedron Lett.  2002,  43:  6987 
    Google Scholar
  • 11f Miyaura N. Suzuki A. Chem. Rev.  1995,  95:  2457 
    Google Scholar
  • 12 Akita Y. Itagaki Y. Takaziwa S. Ohta A. Chem. Pharm. Bull.  1989,  37:  1477 
    CrossrefGoogle Scholar
  • For leading references, see:
  • 13a Glover B. Harvey KA. Liu B. Sharp MJ. Tymoschenko MF. Org. Lett.  2003,  5:  301 
    Google Scholar
  • 13b Masui K. Mori A. Okano K. Takamura K. Kinoshita M. Ikeda T. Org. Lett.  2004,  6:  2011 
    Google Scholar
  • 13c Lane SB. Sames D. Org. Lett.  2004,  6:  2897 
    Google Scholar
  • 13d Sezen B. Sames D. J. Am. Chem. Soc.  2003,  125:  5274 
    Google Scholar
  • 13e Fujita Y. Hiraki K. Kiamogawa Y. Suenaga M. Toggoh K. Fujiwara Y. Bull. Chem. Soc. Jpn.  1989,  62:  1081 
    Google Scholar
  • 13f Jia C. Lu W. Kitamura T. Fujiwara Y. Org. Lett.  1999,  13:  2097 
    Google Scholar
  • 14 Chabert JFD. Gozzi C. Lemaire M. Tetrahedron Lett.  2002,  43:  1829 
    CrossrefGoogle Scholar
  • 15 Chabert JFD. Joucla L. David E. Lemaire M. Tetrahedron  2004,  60:  3221 
    CrossrefGoogle Scholar
  • 16 For a recent review on direct C-H arylations, see: Campeau C.-L. Fagnou K. Chem. Commun.  2006,  1253 
    CrossrefGoogle Scholar
  • 19 For a related mechanism proposed for Pd catalyzed arylations of 2-furfuraldehyde, see: McClure MS. Glover B. McSorley E. Millar A. Osterhout MH. Roschangar F. Org. Lett.  2001,  3:  1677 
    CrossrefPubMedGoogle Scholar
  • 20 That compound 12 containing an acetyl thiophene absorbs at lower energy (λmax 367 nm) than the cyano- or ester-substituted benzene analogues 6 or 10 (λmax 325-336 nm) may not be surprising on account of better charge delocalization available from a relatively less resonance-stabilized thiophene ring than from benzene. For discussion, see: Alobert ID. Marks TJ. Ratner MA. J. Am. Chem. Soc.  1997,  119:  6575 ; and references cited therein
    CrossrefGoogle Scholar
17

Typical procedure: To a solution of 1 (0.168 g, 1 mmol) and appropriate aryl halide (2.1 mmol) in dry DMF (15 mL) were introduced anhyd K2CO3 (0.600 g, ca. 2 mmol), n-Bu4NBr (0.644 g, 2 mmol) and Pd(OAc)2 (10 mg). The reaction mixture was stirred and heated at 80 °C for the time specified (Table [1] ) under a N2 atmosphere. The reaction mixture was allowed to cool to r.t., poured into H2O, extracted with CH2Cl2 and the organic extract dried over anhyd Na2SO4. The crude material obtained on solvent removal was purified by flash column chromatography on silica gel (hexane-CHCl3- mixtures) to obtain the corresponding diaryl thienothiophenes. 4: Yield 70%; mp 300 °C (dec.); IR (KBr): 2922, 1588, 1512, 1417, 1340, 1106, 932, 850, 750, 737, 694, 524, 485 cm-1; 1H NMR (CDCl3, 300 MHz): δ = 2.60 (s, 6 H, CH3), 7.61 (d, J = 10.5 Hz, 4 H, ArH), 8.31 (d, J = 10.5 Hz, 4 H, ArH); Anal. Calcd for C20H14N2O4S2: C, 58.54; H, 3.41; N, 6.83; S, 15.61. Found: C, 58.34; H, 3.63; N, 6.85; S, 15.49. 10: Yield 65%; mp 293-295 °C; IR (KBr): 3423, 2921, 1722, 1604, 1523, 1433, 1403, 1279, 1180, 1104, 1017, 965, 932, 850, 766, 700 cm-1; 1H NMR (CDCl3, 300 MHz): δ = 2.57 (s, 6 H, -CH3), 2.95 (s, 6 H, -OCH3), 7.54 (d, J = 6 Hz, 4 H, ArH), 8.11 (d, J = 6 Hz, 4 H, ArH); Anal. Calcd for C24H20O4S2: C, 66.05; H, 4.60; S, 14.70. Found: C, 66.10; H, 4.52; S, 14.55. 12: Yield 71%; mp >320 °C; IR (KBr): 3070, 2921, 1655, 1510, 1485, 1432, 1360, 1301, 1269, 1088, 1035, 937, 897, 881, 790, 745, 672, 610, 592, 555, 463 cm-1; 1H NMR (CDCl3, 300 MHz): δ = 2.57 (s, 6 H, CH3), 2.67 (s, 6 H, -COCH3), 7.29 (d, J = 3 Hz, 2 H, thiophene H), 7.60 (d, J = 3 Hz, 2 H, thiophene H); Anal. Calcd for C20H16O2S4: C, 57.69; H, 3.90; S, 31.22. Found: C, 57.54; H, 3.85; S, 31.02. 14: Yield 61%; mp 265-268 °C; IR (KBr): 2958, 2837, 1606, 1570, 1525, 1492, 1461, 1439, 1297, 1275, 1248, 1177, 1110, 1041, 1028, 926, 810, 825, 649, 628, 542, 517 cm-1; 1H NMR (CDCl3, 300 MHz): δ = 2.20 (s, 6 H, -CH3), 3.80 (s, 6 H, -OCH3), 6.90 (d, J = 8.0 Hz, 4 H, ArH), 7.35 (d, J = 8.0 Hz, 4 H, ArH); Anal. Calcd for C22H20O2S2: C, 69.47; H, 5.26; S, 16.84. Found: C, 69.31; H, 5.20; S, 16.64. 18: Yield 47%; mp 308-311 °C; IR (KBr): 3086, 2916, 1440, 1418, 1382, 1216, 1158, 1117, 1045, 1034, 999, 961, 902, 863, 830, 809, 736, 725, 564 cm-1; 1H NMR (CDCl3, 300 MHz): δ = 2.35 (s, 6 H, -CH3), 2.50 (s, 6 H, -CH3), 6.85 (s, 2 H, thienothiophene H), 7.30 (s, 4 H, ArH); Anal. Calcd for C22H18S4: C, 64.40; H, 4.40; S, 31.22. Found: C, 64.28; H, 4.42; S, 31.02.

18

The in situ reduction of Pd2+ to Pd0 is conceivable via DMF and or tributylamine mediated processes. Tributylamine in turn could be generated via the Hoffmann elimination of the quarternary ammonium salt under the reaction conditions.