Download PDF
Synlett 2013; 24(11): 1364-1370
DOI: 10.1055/s-0033-1338938
letter
© Georg Thieme Verlag Stuttgart · New York

Construction of Cyclohepta[b]indoles via Platinum-Catalyzed Intermolecular Formal [4+3]-Cycloaddition Reaction of α,β-Unsaturated Carbene Complex Intermediates with Siloxydienes

Hiroyuki Kusama
Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan   Fax: +81(3)57342931   Email: niwasawa@chem.titech.ac.jp
,
Hideyuki Sogo
Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan   Fax: +81(3)57342931   Email: niwasawa@chem.titech.ac.jp
,
Kodai Saito
Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan   Fax: +81(3)57342931   Email: niwasawa@chem.titech.ac.jp
,
Takuya Suga
Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan   Fax: +81(3)57342931   Email: niwasawa@chem.titech.ac.jp
,
Nobuharu Iwasawa*
Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan   Fax: +81(3)57342931   Email: niwasawa@chem.titech.ac.jp
› Author Affiliations
Further Information

Publication History

Received: 11 March 2013

Accepted after revision: 16 April 2013

Publication Date:
15 May 2013 (online)

    Permissions and Reprints All articles of this category


Abstract

Platinum(II)-catalyzed intermolecular formal [4+3]-cycloaddition reaction of α,β-unsaturated carbene complex intermediates with siloxydienes proceeded under mild conditions to give cyclohepta[b]indole derivatives in good yield. The reaction was found to proceed via 1,2-alkyl shift of the carbene complex intermediates obtained by [4+2]-cycloaddition reaction of the unsaturated carbenes with dienes.

Key words

platinum - alkynes - cycloaddition - siloxy diene - cyclohepta[b]indole
 

  • References and Notes

    • 1a Carroll AR, Hyde E, Smith J, Quinn RJ, Guymer G, Forster PI. J. Org. Chem. 2005; 70: 1096
      CrossrefSearch in Google Scholar
    • 1b Kuehm-Caubère C, Caubère P, Jamart-Grégoire B, Pfeiffer B, Guardiola-Lemaître B, Manechez D, Renard P. Eur. J. Med. Chem. 1999; 34: 51
      CrossrefSearch in Google Scholar
    • 1c Raveh A, Carmeli S. J. Nat. Prod. 2007; 70: 196
      CrossrefPubMedSearch in Google Scholar
    • 1d Mo S, Krunic A, Chlipala G, Orjala J. J. Nat. Prod. 2009; 72: 894
      CrossrefSearch in Google Scholar
    • 1e Mo S, Krunic A, Santarsiero BD, Franzblau SG, Orjala J. Phytochemistry (Elsevier) 2010; 71: 2116
      CrossrefSearch in Google Scholar
    • 1f Rawson TE, Rüth M, Blackwood E, Burdick D, Corson L, Dotson J, Drummond J, Fields C, Georges GJ, Goller B, Halladay J, Hunsaker T, Kleinheinz T, Krell H, Li J, Liang J, Limberg A, McNutt A, Moffat J, Phillips G, Ran Y, Safina B, Ultsch M, Walker L, Wiesmann C, Zhang B, Zhou A, Zhu B, Rüger P, Cochran AG. J. Med. Chem. 2008; 51: 4465
      CrossrefSearch in Google Scholar
    • 1g Napper AD, Hixon J, McDonagh T, Keavey K, Pons J, Barker J, Yau WT, Amouzegh P, Flegg A, Hamelin E, Thomas RJ, Kates M, Jones S, Navia MA, Saunders JO, DiStefano PS, Curtis R. J. Med. Chem. 2005; 48: 8045
      CrossrefPubMedSearch in Google Scholar
    • 1h Mewshaw RE, Silverman LS, Mathew RM, Kaiser C, Sherrill RG, Cheng M, Tiffany CW, Karbon EW, Bailey MA, Borosky SA, Ferkany JW, Abreu ME. J. Med. Chem. 1993; 36: 1488
      CrossrefSearch in Google Scholar
    • 1i Kuehm-Caubere C, Caubere P, Jamart-Gregoire B, Negre-Salvayre A, Bonnefont-Rousselot D, Bizot-Espiard J, Pfeiffer B, Caignard D, Guardiola-Lemaitre B, Renard P. J. Med. Chem. 1997; 40: 1201
      CrossrefSearch in Google Scholar
  • 4 Amat M, Checa B, Llor N, Molins E, Bosch J. Chem. Commun. 2009; 2935
  • 6 Han X, Li H, Hughes RP, Wu J. Angew. Chem. Int. Ed. 2012; 51: 10390
    Search in Google Scholar
  • 7 Saito K, Sogou H, Suga T, Kusama H, Iwasawa N. J. Am. Chem. Soc. 2011; 133: 689
    CrossrefPubMedSearch in Google Scholar
  • 8 Theoretical investigation on the Pt(II)-catalyzed [3+2]-cycloaddition reactions: Liu T, Han L, Liu Y, Zhang D, Li W. Comput. Theor. Chem. 2012; 992: 97
    CrossrefSearch in Google Scholar
  • 12 During the preparation of this manuscript, Prof. Tang’s report on the same type of reaction appeared. Our reaction conditions are milder (r.t. vs. 100 °C) and their proposed reaction mechanisms are different from ours. See: Shu D, Song W, Li X, Tang W. Angew. Chem. Int. Ed. 2013; 52: 3237
    CrossrefPubMedSearch in Google Scholar
  • 13 The tetracyclic compound 7 was obtained as a single diastereomer because the other diastereomers are too strained to produce
  • 14 Tolman CA. Chem. Rev. 1977; 77: 313
    Search in Google Scholar
  • 16 In the reactions using P(C6F5)3 as ligand, product 6b was obtained as follows: MS 4 Å, 89%; MS 5 Å, 82%; none, 83%.
  • 17 There still remains a possibility of an alternative pathway that the [4+3]-cycloaddition product was obtained to some extent via ring closure of the indole nucleus at the C-3 carbon to the α,β-unsaturated silyl oxonium moiety in a 1,4-addition manner to directly give the seven-membered-ring product (Scheme 5).
  • 19 Tetracyclic compound 7a was not isomerized to the [4+3]-cycloaddition product 6a under the reaction conditions, and only 7a was recovered.
  • 22 Selected Compound Data Compound 6a: colorless oil. IR (neat): 3049, 2944, 2867, 1730, 1667, 1458, 1369, 1355, 1149, 1119, 742, 683 cm–1. 1H NMR (500 MHz, CDCl3): δ = 0.95 (t, J = 7.3 Hz, 3 H), 1.09–1.13 (m, 18 H), 1.15–1.25 (m, 3 H), 1.38–1.48 (m, 1 H), 1.48–1.57 (m, 1 H), 1.69 (s, 9 H), 1.70–1.79 (m, 2 H), 2.40 (ddd, J = 3.2, 8.2, 15.4 Hz, 1 H), 2.78 (ddd, J = 2.9, 10.3, 15.4 Hz, 1 H), 3.20 (ddd, J = 2.9, 8.2, 16.9 Hz, 1 H), 3.44–3.53 (m, 2 H), 5.24 (d, J = 8.1 Hz, 1 H), 7.19–7.25 (m, 2 H), 7.38–7.42 (m, 1 H), 8.02–8.07 (m, 1 H). 13C NMR (125 MHz in CDCl3): δ = 12.6, 14.2, 18.04, 18.05, 21.7, 25.3, 28.3, 32.2, 32.4, 39.2, 83.5, 107.4, 115.2, 117.5, 121.7, 122.2, 123.2, 130.2, 135.1, 136.6, 150.8, 153.1. HRMS–FAB: m/z [M]+ calcd for C30H47NO3Si: 497.3325; found: 497.3346. Compound 7a: colorless oil. IR (neat): 3048, 2944, 2867, 1709, 1656, 1478, 1368, 1347, 1224, 1178, 883, 749, 684 cm–1. 1H NMR (500 MHz, CDCl3, 330 K): δ = 0.72 (t, J = 7.4 Hz, 3 H), 0.94–0.99 (m, 2 H), 1.11–1.15 (m, 18 H), 1.15–1.25 (m, 3 H), 1.25–1.44 (m, 2 H), 1.58 (s, 9 H), 2.12–2.20 (m, 2 H), 2.23–2.31 (m, 1 H), 2.47 (s, 1 H), 2.90–3.04 (m, 1 H), 5.16 (s, 1 H), 6.91 (dt, J = 0.9, 7.4 Hz, 1 H), 7.10–7.15 (m, 2 H), 7.68–7.75 (m, 1 H). 13C NMR (125 MHz, CDCl3, 330 K): δ = 12.8, 14.1, 18.0, 19.8, 24.8, 25.8, 27.8, 28.5, 28.9, 39.7, 55.3, 81.3, 107.3, 115.0, 122.3, 124.6, 126.7, 130.1, 145.9, 150.5, 153.2. HRMS–FAB: m/z [M]+ calcd for C30H47NO3Si: 497.3325; found: 497.3329. Compound 6h: colorless oil. IR (neat): 3050, 2942, 2866, 1730, 1655, 1456, 1357, 1132, 1117, 883, 743, 687 cm–1. 1H NMR (500 MHz in CDCl3): δ = 1.06–1.10 (m, 18 H), 1.13–1.23 (m, 3 H), 1.66 (s, 9 H), 1.81–1.93 (m, 2 H), 2.03–2.13 (m, 2 H), 2.76–2.80 (m, 1 H), 3.10 (dd, J = 4.6, 18.2 Hz, 1 H), 3.44 (br d, J = 18.2 Hz, 1 H), 3.53–3.57 (m, 1 H), 5.53 (dd, J = 1.8, 7.9 Hz, 1 H), 7.18–7.22 (m, 2 H), 7.42–7.47 (m, 1 H), 8.05–8.10 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 12.6, 17.97, 17.99, 25.9, 28.2, 28.3, 31.7, 35.6, 37.8, 83.3, 109.4, 115.4, 116.9, 122.1, 123.0, 123.4, 128.8, 133.9, 134.9, 150.7, 154.0. HRMS–FAB: m/z [M]+ calcd for C29H43NO3Si: 481.3012; found: 481.3021. Compound 9: pale yellow oil. IR (neat): 3046, 2945, 2866, 1663, 1598, 1452, 1381, 1367, 1173, 746, 684 cm–1. 1H NMR (500 MHz, CDCl3): δ = 0.75 (d, J = 6.8 Hz, 3 H), 0.89 (d, J = 6.6 Hz, 3 H), 1.02–1.07 (m, 18 H), 1.08–1.18 (m, 3 H), 1.90–2.00 (m, 1 H), 2.06–2.16 (m, 1 H), 2.32 (s, 3 H), 2.41 (ddd, J = 3.2, 6.4, 16.8 Hz, 1 H), 3.11 (ddd, J = 3.2, 11.7, 16.1 Hz, 1 H), 3.23 (t, J = 7.4 Hz, 1 H), 3.64 (ddd, J = 3.5, 6.4, 16.1 Hz, 1 H), 5.12 (dd, J = 0.7, 7.4 Hz, 1 H), 7.14 (d, J = 8.2 Hz, 2 H), 7.21–7.29 (m, 2 H), 7.33–7.36 (m, 1 H), 7.51–7.55 (m, 2 H), 8.22–8.26 (m, 1 H). 13C NMR (125 MHz, CDCl3): δ = 12.6, 17.97, 17.99, 20.5, 21.5, 21.7, 22.8, 31.7, 35.2, 39.7, 105.9, 115.4, 118.3, 123.3, 123.8, 124.3, 126.1, 129.6, 131.4, 136.1, 136.3, 136.4, 144.5, 152.0. HRMS–FAB: m/z [M]+ calcd for C32H45NO3SSi: 551.2889; found: 551.2881.