Download PDF
Synthesis 2009(23): 4010-4014  
DOI: 10.1055/s-0029-1217052
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Microwave-Assisted Solid-Acid-Catalyzed Friedel-Crafts Alkylation and Electrophilic Annulation of Indoles Using Alcohols as Alkylating Agents

Aditya Kulkarni, Phong Quang, Béla Török*
Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA
Fax: +1(617)2876030; e-Mail: bela.torok@umb.edu;
Further Information

Publication History

Received 29 April 2009
Publication Date:
19 October 2009 (online)

    Permissions and Reprints All articles of this category

Abstract

Alcohols are considered environmentally benign alkylating agents since the only by-product generated in their reactions is water. Herein, we report a microwave-assisted Friedel-Crafts alkylation and electrophilic annulation of indoles using alcohols as alkylating agents. Alkylation of indoles using tert-butyl alcohol gives 3-substituted tert-butylindoles. A domino electrophilic annulation/aromatization­ of indoles using hexane-2,5-diol results in the formation of substituted carbazoles. The reaction is catalyzed by a strong, solid-acid catalyst montmorillonite K-10. The products were obtained in good yields and high selectivities.

Key words

alkylation - carbazoles - indole - tert-butyl alcohol - hexane-2,5-diol - montmorillonite K-10 - microwave heating - annulation

    References

  • 1a Gribble GW. J. Chem. Soc., Perkin Trans. 1  2000,  1045 
    Google Scholar
  • 1b Nobuyoshi A. Akihiko O. Chikara M. Tatsuya T. Masami O. Hiromitsu S. J. Med. Chem.  1999,  42:  2946 
    Google Scholar
  • 1c Török M. Abid M. Mhadgut SC. Török B. Biochemistry  2006,  45:  5377 
    Google Scholar
  • 2a Cacchi B. Fabrizi G. Chem. Rev.  2005,  105:  2873 
    Google Scholar
  • 2b Török B. Abid M. London G. Esquibel J. Török M. Mhadgut SC. Yan P. Prakash GKS. Angew. Chem. Int. Ed.  2005,  44:  3086 
    Google Scholar
  • 2c Abid M. Teixeira L. Török B. Org. Lett.  2008,  10:  933 
    Google Scholar
  • 3a Heaney H. In Comprehensive Organic Synthesis   Vol. 2:  Trost BM. Fleming I. Pergamon; Oxford: 1991.  p.733 
    Google Scholar
  • 3b Heaney H. In Comprehensive Organic Synthesis   Vol. 2:  Trost BM. Fleming I. Pergamon; Oxford: 1991.  p.753 
    Google Scholar
  • 3c Olah GA. Krishnamurti R. Prakash GKS. In Comprehensive Organic Synthesis   Vol. 1:  Trost BM. Fleming I. Pergamon; Oxford: 1991.  p.293 
    Google Scholar
  • 3d Yonezawa N. Hino T. Ikeda T. Recent Res. Dev. Synth. Org. Chem.  1998,  1:  213 
    Google Scholar
  • 3e Friedel-Crafts and Related Reactions   Olah GA. Wiley; New York: 1963-1965. 
    Google Scholar
  • 3f Olah GA. Török B. Shamma T. Török M. Prakash GKS. Catal. Lett.  1996,  42:  5 
    Google Scholar
  • 3g Beregszászi T. Török B. Molnár Á. Olah GA. Prakash GKS. Catal. Lett.  1997,  48:  83 
    Google Scholar
  • 3h Török B. Kiricsi I. Molnár Á. Olah GA. J. Catal.  2000,  193:  132 
    Google Scholar
  • 3i Olah GA. Török B. Joschek JP. Bucsi I. Estevez PM. Rasul G. Prakash GKS. J. Am. Chem. Soc.  2002,  124:  11379 
    Google Scholar
  • 4a Chung JYL. Dormer PG. Variankaval N. Ball RG. Tsou NN. Org. Lett.  2008,  10:  3037 
    Google Scholar
  • 4b Sui Y. Liu L. Zhao J. Wang D. Chen Y. Tetrahedron  2007,  63:  5173 
    Google Scholar
  • 4c Lu S. Du D. Xu J. Org. Lett.  2006,  8:  2115 
    Google Scholar
  • 4d Li D. Guo Y. Ding Y. Xiao W. Chem. Commun.  2006,  799 
    Google Scholar
  • 4e Jia Y. Zhu S. Yang Y. Zhou Q. J. Org. Chem.  2006,  71:  75 
    Google Scholar
  • 5a Yadav JS. Subba Reddy BV. Rao KVR. Narayan Kumar GGKS. Tetrahedron Lett.  2007,  48:  5573 
    Google Scholar
  • 5b Jana U. Maiti S. Biswas S. Tetrahedron Lett.  2007,  48:  7160 
    Google Scholar
  • 5c Whitney S. Grigg R. Derrick A. Keep A. Org. Lett.  2007,  9:  3299 
    Google Scholar
  • 5d Matsuzawa H. Kanao K. Miyake Y. Nishibayashi Y. Org. Lett.  2007,  9:  5561 
    Google Scholar
  • 6 Dasgupta S. Török B. Curr. Org. Synth.  2008,  5:  321 
    CrossrefGoogle Scholar
  • 7a Corma A. Chem. Rev.  1995,  95:  559 
    Google Scholar
  • 7b Gates BC. Catalysis by Solid Acids, In Encyclopedia of Catalysis   Vol. 2:  Horváth I. Wiley; New York: 2003.  p.104 
    Google Scholar
  • 7c Yip ACK. Lam FLY. Hu XJ. Chem. Commun.  2005,  3218 
    Google Scholar
  • 7d Varma RS. Tetrahedron  2002,  58:  1235 
    Google Scholar
  • 8 Yadav GD. Kamble SB. Ind. Eng. Chem. Res.  2009,  48:  in press; DOI: 10.1021/ie800737v
    Google Scholar
  • 9 Velu S. Swamy CS. Res. Chem. Intermed.  2000,  26:  295 
    CrossrefGoogle Scholar
  • 10a Balogh M. Laszlo P. Organic Chemistry Using Clays   Springer-Verlag; Berlin: 1993. 
    Google Scholar
  • 10b Kappe CO. Stadler A. Microwaves in Organic and Medicinal Chemistry   Wiley-VCH; Weinheim: 2005. 
    Google Scholar
  • 10c Li A. Li T. Ding T. Chem. Commun.  1997,  1389 
    Google Scholar
  • 10d Polshettiwar V. Varma RS. Acc. Chem. Res.  2008,  41:  629 
    Google Scholar
  • 10e Dasgupta S. Török B. Org. Prep. Proced. Int.  2008,  40:  1 
    Google Scholar
  • 12 Abid M. Spaeth A. Török B. Adv. Synth. Catal.  2006,  348:  2191 
    CrossrefGoogle Scholar
  • 13 Knöler HJ. Reddy KR. Chem. Rev.  2002,  102:  4303 
    CrossrefPubMedGoogle Scholar
  • 14 Iraqi A. Wataru I. Chem. Mater.  2004,  16:  442 
    CrossrefGoogle Scholar
  • 15a Knölker HJ. Curr. Org. Synth.  2004,  1:  309 
    Google Scholar
  • 15b Sanz R. Escribano J. Pedrosa MR. Aguado R. Arnàiz FJ. Adv. Synth. Catal.  2007,  349:  713 
    Google Scholar
  • 16a Kulkarni A. Abid M. Török B. Huang X. Tetrahedron Lett.  2009,  50:  1791 
    Google Scholar
  • 16b De Paolis O. Teixeira L. Török B. Tetrahedron Lett.  2009,  50:  2939 
    Google Scholar
  • 17 Török B. Bucsi I. Beregszászi T. Kapocsi I. Molnár Á. J. Mol. Catal. A: Chem.  1996,  107:  305 
    Google Scholar
  • 18a Molnár Á. Török B. Bucsi I. Földvári A. Top. Catal.  1998,  6:  9 
    Google Scholar
  • 18b Molnár Á. Ledneczki I. Bucsi I. Bartók M. Catal. Lett.  2003,  89:  1 
    Google Scholar
  • 18c Ledneczki I. Forgo P. Molnár Á. Catal. Lett.  2007,  119:  296 
    Google Scholar
  • 19 Landge S. Atanassova V. Thimmaiah M. Török B. Tetrahedron Lett.  2007,  48:  5161 
    CrossrefGoogle Scholar
11

While a minimal amount of solvent was used during the sample preparation and product isolation, the reaction itself occurred under solvent-free conditions. Thus, the complete process is not solvent-free.