Synlett 2021(18): 2708-2710  
DOI: 10.1055/s-0030-1259003
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Towards a Practical Brønsted Acid Catalyzed and Hantzsch Ester Mediated Asymmetric Reductive Amination of Ketones with Benzylamine

Vijay N. Wakchaure, Marcello Nicoletti, Lars Ratjen, Benjamin List*
Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
Fax: +49(208)3062982; e-Mail: list@mpi-muelheim.mpg.de;
Further Information

Publication History

Received 24 August 2010
Publication Date:
14 October 2010 (online)

  Permissions and Reprints All articles of this category
Preview

Abstract

We report the use of benzylamine as the amine component in Hantzsch ester mediated and chiral Brønsted acid catalyzed enantioselective reductive aminations of ketones. The method is noteworthy because the benzyl group is easily removable, and amine product purification is achieved through Hantzsch ester oxidation product removal via basic hydrolysis.

Key words

benzylamine - Hantzsch ester - reductive amination - ­organocatalysis - chiral amines - Brønsted acids

    References and Notes

  • For a review on asymmetric reductive aminations, see:
  • 1a Tararov VI. Börner A. Synlett  2005,  203 
  • For reviews on catalytic asymmetric imine reductions, see:
  • 1b Ohkuma T. Kitamura M. Noyori R. In Catalytic Asymmetric Synthesis   2nd ed.:  Ojima I. Wiley-VCH; New York: 2000.  Chap. 1.
    Search in Google Scholar
  • 1c Ohkuma T. Noyori R. In Comprehensive Asymmetric Catalysis   Suppl. 1:  Jacobsen EN. Pfaltz A. Yamamoto H. Springer; New York: 2004.  p.43 
    Search in Google Scholar
  • 1d Nishiyama H. Itoh K. In Catalytic Asymmetric Synthesis   2nd ed.:  Ojima I. Wiley-VCH; New York: 2000. 
    Search in Google Scholar
  • 1e Blaser H.-U. Buser H.-P. Jalett H.-P. Pugin B. Spindler F. Synlett  1999,  867 
  • 1f Kadyrov R. Riermeier TH. Angew. Chem. Int. Ed.  2003,  42:  5472 
    Search in Google Scholar
  • 1g Williams GD. Pike RA. Wade CE. Wills M. Org. Lett.  2003,  5:  4227 
    Search in Google Scholar
  • 1h Kadyrov R. Riermeier TH. Dingerdissen U. Tararov V. Börner A. J. Org. Chem.  2003,  68:  4067 
    Search in Google Scholar
  • 1i Chi YX. Zhou YG. Zhang XM. J. Org. Chem.  2003,  68:  4120 
    Search in Google Scholar
  • 2 Hoffmann S. Seayad AM. List B. Angew. Chem. Int. Ed.  2005,  44:  7424 
    CrossrefPubMedSearch in Google Scholar
  • For other organocatalytic asymmetric reductive aminations and imine reductions, see:
  • 3a Rueping M. Sugiono E. Azap C. Theissmann T. Bolte M. Org. Lett.  2005,  7:  3781 
    Search in Google Scholar
  • 3b Storer RI. Carrera DE. Ni Y. MacMillan DWC. J. Am. Chem. Soc.  2006,  128:  84 
    Search in Google Scholar
  • 3c Singh S. Batra UK. Indian J. Chem., Sect. B: Org. Chem. Incl. Med. Chem.  1989,  28:  1 ; please note that so far, we have been unable to reproduce any of the enantioselectivities reported in this paper
    Search in Google Scholar
  • For organocatalytic asymmetric of α-imino ester reductions, see:
  • 3d Li G. Liang Y. Antilla JC. J. Am. Chem. Soc.  2007,  129:  5830 
    Search in Google Scholar
  • 3e Kang Q. Zhao Z.-A. You S.-L. Adv. Synth. Catal.  2007,  349:  1657 
    Search in Google Scholar
  • For a theoretical study, see:
  • 3f Simón L. Goodman JM. J. Am. Chem. Soc.  2008,  130:  8741 
    Search in Google Scholar
  • For a review, see:
  • 3g Connon SJ. Org. Biomol. Chem.  2007,  5:  3407 
    Search in Google Scholar
  • For organo-catalytic asymmetric enamide reductions, see:
  • 3h Li G. Antilla JC. Org. Lett.  2009,  11:  1075 
    Search in Google Scholar
  • For selected examples of Lewis base catalyzed asymmetric imine reduction using silanes, see:
  • 3i Iwasaki F. Onomura O. Mishima K. Kanematsu T. Maki T. Matsumura Y. Tetrahedron Lett.  2001,  42:  2525 
    Search in Google Scholar
  • 3j Malkov AV. Mariani A. MacDougall KN. Kočovský P. Org. Lett.  2004,  6:  2253 
    Search in Google Scholar
  • 3k Malkov AV. Stoncius S. MacDougall KN. Mariani A. McGeoch GD. Kočovský P. Tetrahedron  2006,  62:  264 
    Search in Google Scholar
  • 3l Wang Z. Ye X. Wei S. Wu P. Zhang A. Sun J. Org. Lett.  2006,  8:  999 
    Search in Google Scholar
  • 3m Pei D. Zhang Y. Wei S. Wang M. Sun J. Adv. Synth. Catal.  2008,  350:  619 
    Search in Google Scholar
  • 3n Wang C. Wu X. Zhou L. Sun J. Chem. Eur. J.  2008,  14:  8789 
    Search in Google Scholar
  • 3o Wu PC. Wang ZY. Cheng MN. Zhou L. Sun J. Tetrahedron  2008,  64:  11304 
    Search in Google Scholar
  • 3p Gautier F.-M. Jones S. Martin SJ. Org. Biomol. Chem.  2009,  7:  229 
    Search in Google Scholar
  • 3q Guizzetti S. Benaglia M. Cozzi F. Rossi S. Celentano G. Chirality  2009,  21:  233 
    Search in Google Scholar
  • For structural and mechanistic studies, see:
  • 3r Zhang Z. Rooshenas P. Hausmann H. Schreiner PR. Synthesis  2009,  1531 
  • 4a Adair G. Mukherjee S. List B. Aldrichimica Acta  2008,  41:  31 
    Search in Google Scholar
  • For pioneering studies on the use of chiral phosphoric acid catalysts, see:
  • 4b Akiyama T. Itoh J. Yokota K. Fuchibe K. Angew. Chem. Int. Ed.  2004,  43:  1566 
    Search in Google Scholar
  • 4c Uraguchi D. Terada M. J. Am. Chem. Soc.  2004,  126:  5356 
    Search in Google Scholar
  • For reviews, see:
  • 4d Connon SJ. Angew. Chem. Int. Ed.  2006,  45:  3909 
    Search in Google Scholar
  • 4e Akiyama T. Chem. Rev.  2007,  107:  5744 
    Search in Google Scholar
  • 4f Terada M. Chem. Commun.  2008,  4097 
  • Also see:
  • 4g Guo Q.-X. Liu H. Guo C. Luo S.-W. Gu Y. Gong L.-Z. J. Am. Chem. Soc.  2007,  129:  3790 
    Search in Google Scholar
  • 4h Jia Y.-X. Zhong J. Zhu S.-F. Zhang C.-M. Zhou Q.-L. Angew. Chem. Int. Ed.  2007,  46:  5565 
    Search in Google Scholar
  • 4i Jiao P. Nakashima D. Yamamoto H. Angew. Chem. Int. Ed.  2008,  47:  2411 
    Search in Google Scholar
  • 5 Hoffmann S. Nicoletti M. List B. J. Am. Chem. Soc.  2006,  128:  13074 
    CrossrefPubMedSearch in Google Scholar
  • 6a Sakai T. Korenaga T. Washio N. Nishio Y. Minami S. Ema T. Bull. Chem. Soc. Jpn.  2004,  77:  1001 
    Search in Google Scholar
  • 6b Hata S. Iguchi I. Iwasawa T. Yamada K. Tomioka K. Org. Lett.  2004,  6:  1721 
    Search in Google Scholar
  • 6c Overman LE. Owen CE. Pavan MP. Org. Lett.  2003,  5:  1809 
    Search in Google Scholar
  • 6d Chi Y. Zhou Y.-G. Zhang X. J. Org. Chem.  2003,  68:  4120 
    Search in Google Scholar
  • 6e Fustero S. Garcia Soler J. Bartolomé A. Sanchez-Rosello M. Org. Lett.  2003,  5:  2707 
    Search in Google Scholar
  • 6f Fustero S. Bartolomé A. Sanz-Cervera JF. Sanchez-Rosello M. Soler JG. Ramirez de Arellano C. Fuentes AS. Org. Lett.  2003,  5:  2523 
    Search in Google Scholar
  • 6g Córdova A. Synlett  2003,  1651 
  • 7a Verkade JMM. van Hermert LJC. Quaedflieg PJLM. Alsters PL. van Delft FL. Rutjes FPJT. Tetrahedron Lett.  2006,  47:  8109 
    Search in Google Scholar
  • 7b Verkade JMM. van Hermert LJC. Quaedflieg PJLM. Schoemaker HE. Schürmann M. van Delft FL. Rutjes FPJT. Adv. Synth. Catal.  2007,  349:  1332 
    Search in Google Scholar
8

The absolute configuration of amine 5a was established via comparing the HPLC chromatogram with authentic sample of (S)-5a.