Download PDF
Synlett 2005(20): 3151-3153  
DOI: 10.1055/s-2005-921927
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthetic Radical Reactions Using Dibutylchlorogermane and ­Dibutylethoxygermane as Radical Mediators

Katsukiyo Miura*a, Kazunori Ootsukaa, Akira Hosomi*a,b
a Department of Chemistry, 21st Century COE, Graduate School of Pure and Applied Sciences, University of Tsukuba, and CREST, Japan Science and Technology Corporation (JST), Tsukuba, Ibaraki 305-8571, Japan
Fax: +81(29)8536503; e-Mail: miura@chem.tsukuba.ac.jp; e-Mail: hosomi@chem.tsukuba.ac.jp;
b Faculty of University Evaluation and Research, National Institution for Academic Degrees and University Evaluation, Kodaira, Tokyo 187-8587, Japan
Further Information

Publication History

Received 28 September 2005
Publication Date:
28 November 2005 (online)

    Permissions and Reprints All articles of this category

Abstract

In the presence of Et3B as radical initiator, dibutylchlorogermane (1a) and dibutylethoxygermane (1b) reacted with bromo- and iodoalkanes at room temperature to give the corresponding alkanes in high yields. Hydrogermane 1a was more reactive than 1b. However, 1b worked as a better radical mediator in intermolecular radical addition of haloalkanes to electron-deficient alkenes.

Key words

addition reactions - halides - organometallic reagents - radical reactions - reductions

    References

  • 1a Renaud P. Sibi MP. Radicals in Organic Synthesis   Wiley-VCH; Weinheim: 2001. 
    Google Scholar
  • 1b Curran DP. Porter NA. Giese B. Stereochemistry of Radical Reactions   VCH; Weinheim: 1996. 
    Google Scholar
  • 1c Curran DP. In Comprehensive Organic Synthesis   Vol. 4:  Trost BM. Fleming I. Pergamon Press; Oxford: 1991.  Chap. 4.1 and 4.2. p.715 
    Google Scholar
  • 1d Giese B. Radicals in Organic Synthesis: Formation of Carbon-Carbon Bonds   Pergamon Press; Oxford: 1986. 
    Google Scholar
  • 2 Boyer IJ. Toxicology  1989,  55:  253 
    CrossrefGoogle Scholar
  • 3 Baguley PA. Walton JC. Angew. Chem. Int. Ed.  1998,  37:  3073 ; and references therein
    Google Scholar
  • 4a Giese B. Kopping B. Chatgilialoglu C. Tetrahedron Lett.  1989,  30:  681 
    CrossrefGoogle Scholar
  • 4b Chatgilialoglu C. Acc. Chem. Res.  1992,  25:  188 
    CrossrefGoogle Scholar
  • 4c Chatgilialoglu C. Guerra M. Guerrini A. Seconi G. J. Org. Chem.  1992,  57:  2427 
    CrossrefGoogle Scholar
  • 4d Yamazaki O. Togo H. Matsubayashi S. Yokoyama M. Tetrahedron  1999,  55:  3735 
    CrossrefGoogle Scholar
  • 4e Studer A. Amrein S. Schleth F. Schulte T. Walton JC. J. Am. Chem. Soc.  2003,  125:  5726 
    CrossrefGoogle Scholar
  • 5a Sakurai H. Mochida K. Hosomi A. Mita F. J. Organomet. Chem.  1972,  38:  275 
    CrossrefGoogle Scholar
  • 5b Chatgilialoglu C. Ballestri M. Organometallics  1995,  14:  5017 
    CrossrefGoogle Scholar
  • 5c Nakamura T. Yorimitsu H. Shinokubo H. Oshima K. Bull. Chem. Soc. Jpn.  2001,  74:  747 
    CrossrefGoogle Scholar
  • For the hydrogermane-mediated intermolecular radical addition of iodoalkanes, see:
  • 6a Pike P. Hershberger S. Hershberger J. Tetrahedron Lett.  1985,  26:  6289 
    CrossrefGoogle Scholar
  • 6b Pike P. Hershberger S. Hershberger J. Tetrahedron  1988,  44:  6295 
    CrossrefGoogle Scholar
  • 7a Inoue K. Sawada A. Shibata I. Baba A. J. Am. Chem. Soc.  2002,  124:  906 
    CrossrefGoogle Scholar
  • 7b Hayashi N. Shibata I. Baba A. Org. Lett.  2005,  7:  3093 
    CrossrefGoogle Scholar
  • 7c Takami K. Mikami S. Yorimitsu H. Shinokubo H. Oshima K. Tetrahedron  2003,  59:  6627 ; and references therein
    CrossrefGoogle Scholar
  • 8 Barton DHR. Jang DO. Jaszberenyi JC. J. Org. Chem.  1993,  58:  6838 ; and references therein
    CrossrefGoogle Scholar
  • 9a The preparation of 1a was carried out by the following steps: butylation of GeCl4 with BuMgBr, dealkylative dichlorination of Bu4Ge with AlCl3 and AcCl, reduction of Bu2GeCl2 with LiAlH4, and chlorination of Bu2GeH2 with CuCl2. For the last step, see: Ohshita J. Toyoshima Y. Iwata A. Tang H. Kunai A. Chem. Lett.  2001,  886 
    Google Scholar
  • 9b For the preparation of 1a, see also: Satge J. Ann. Chim.  1961,  6:  519 
    Google Scholar
  • 11a Newcomb M. Horner JH. Filipkowski MA. Ha C. Park S.-U. J. Am. Chem. Soc.  1995,  117:  3674 
    CrossrefGoogle Scholar
  • 11b Gualtieri G. Geib SJ. Curran DP. J. Org. Chem.  2003,  68:  5013 
    CrossrefGoogle Scholar
  • 12 Newcomb M. In Radicals in Organic Synthesis   Vol. 1:  Renaud P. Sibi MP. Wiley-VCH; Weinheim: 2001.  Chap. 3.1. p.317 
    Google Scholar
  • 13 The reported value for k H(1c) at 80 °C is 3.8 × 105 M-1s-1. See: Chatgilialoglu C. Ballestri M. Escudié J. Pailhous I. Organometallics  1999,  18:  2395 
    CrossrefGoogle Scholar
10

The use of Bu2SnH2 as reducing agent was also attempted for the reduction of 2a. The Et3B-initiated reaction with Bu2SnH2 (1.2 equiv) for 24 h gave 3a in 34% yield with recovery of 2a (ca. 50%).