Download PDF
Synlett 2018; 29(18): 2417-2421
DOI: 10.1055/s-0037-1610298
letter
© Georg Thieme Verlag Stuttgart · New York

Selective Deprotection of N-Tosyl Alkoxyamines Using Bistrifluoromethane Sulfonimide: Formation of Oxime Ethers

Mohamed Salah Azizi
,
Janine Cossy  *
Laboratory of Organic Chemistry, Institute of Chemistry, Biology and Innovation (CBI), ESPCI Paris, PSL Research University, CNRS, 10 Rue Vauquelin, 75231 – Paris Cedex 05, France   Email: Janine.Cossy@espci.fr
› Author Affiliations
Further Information

Publication History

Received: 24 July 2018

Accepted after revision: 12 September 2018

Publication Date:
02 October 2018 (online)

    Permissions and Reprints All articles of this category


Abstract

The detosylation of N-tosyl alkoxyamines was realized by treatment with benzaldehyde and bistrifluoromethane sulfonimide as the catalyst to afford the corresponding oxime ethers. The reaction is chemoselective as N-tosyl amines are not deprotected. A mechanism is proposed for this deprotection.

Key words

N-detosylation - bistrifluoromethane sulfonimide - N-tosyl-alkoxyamine - benzaldehyde - oxime ethers

Supporting Information

    Supporting information for this article is available online at https://doi.org/10.1055/s-0037-1610298.
  • Supporting Information
 

  • References and Notes

    • 1a Maia HL. S. Medeiros MJ. Montenegro MI. Court D. Pletcher D. J. Electroanal. Chem. 1984; 164: 347
    • 1b Civitello ER. Rapoport H. J. Org. Chem. 1992; 57: 834
      Crossref
    • 1c Coeffard V. Thobie-Gautier C. Beaudet I. Le Grognec E. Quintard JP. Eur. J. Org. Chem. 2008; 383
  • 2 Alonso E. Ramón DJ. Yus M. Tetrahedron 1997; 53: 14355
    Crossref
    • 3a Dahlén A. Hilmersson G. Tetrahedron Lett. 2002; 43: 7197
      Crossref
    • 3b Dahlén A. Hilmersson G. Chem. Eur. J. 2003; 9: 1123
      CrossrefPubMed
    • 3c Dahlén A. Hilmersson G. Tetrahedron Lett. 2003; 44: 2661
      Crossref
    • 3d Dahlén A. Hilmersson G. Knettle BW. Flowers RA. J. Org. Chem. 2003; 68: 4870
      CrossrefPubMed
    • 3e Dahlén A. Petersson A. Hilmersson G. Org. Biomol. Chem. 2003; 1: 2423
      CrossrefPubMed
    • 3f Kim M. Dahlén A. Hilmersson G. Knettle BW. Flowers RA. II. Tetrahedron 2003; 59: 10397
      Crossref
    • 3g Dahlén A. Sundgren A. Lahmann M. Oscarson S. Hilmersson G. Org. Lett. 2003; 5: 4085
      CrossrefPubMed
    • 3h Davis TA. Chopade PR. Hilmersson G. Flowers RA. Org. Lett. 2005; 7: 119
      CrossrefPubMed
    • 3i Dahlén A. Hilmersson G. J. Am. Chem. Soc. 2005; 127: 8340
      CrossrefPubMed
    • 3j Dahlén A. Nilsson Å. Hilmersson G. J. Org. Chem. 2006; 71: 1576
      CrossrefPubMed
    • 3k Ankner T. Hilmersson G. Tetrahedron Lett. 2007; 48: 5707
      Crossref
  • 4 Greene TW. Wuts PG. M. Protective Groups in Organic Synthesis . John Wiley and Sons; New York: 2007. 4th ed.
    Google Scholar
  • 5 Milburn RR. Snieckus V. Angew. Chem. Int. Ed. 2004; 43: 892
    Crossref
  • 6 Vellemäe E. Lebedev O. Mäeorg U. Tetrahedron Lett. 2008; 49: 1373
    Crossref
    • 7a Nyasse B. Ragnarsson U. Chem. Commun. 1997; 1017
    • 7b Sridhar M. Kumar BA. Narender R. Tetrahedron Lett. 1998; 39: 2847
      Crossref
  • 8 Knowles HS. Parsons AF. Pettifer RM. Rickling S. Tetrahedron 2000; 56: 979
    Crossref
  • 9 Lefenfeld M. Dye JL. Nandi P. Jackson J. WO 2007095276, 2007
  • 10 Uchiyama M. Matsumoto Y. Nakamura S. Ohwada T. Kobayashi N. Yamashita N. Matsumiya A. Sakamoto T. J. Am. Chem. Soc. 2004; 126: 8755
    CrossrefPubMed
    • 11a Vedejs E. Lin S. J. Org. Chem. 1994; 59: 1602
      Crossref
    • 11b Alonso DA. Andersson PG. J. Org. Chem. 1998; 63: 9455
      Crossref
    • 11c Fujihara H. Nagai K. Tomioka K. J. Am. Chem. Soc. 2000; 122: 12055
      Crossref
    • 11d Hayashi T. Kawai M. Tokunaga N. Angew. Chem. Int. Ed. 2004; 43: 6125
      Crossref
    • 11e Kuriyama M. Soeta T. Hao X. Chen Q. Tomioka K. J. Am. Chem. Soc. 2004; 126: 8128
      CrossrefPubMed
    • 11f Grach G. Santos JS. O. Lohier J. Mojovic L. Plé N. Turck A. Reboul V. Metzner P. J. Org. Chem. 2006; 71: 9572
      CrossrefPubMed
    • 11g Duan H. Jia Y. Wang L. Zhou Q. Org. Lett. 2006; 8: 2567
      CrossrefPubMed
  • 13 Ankner T. Hilmersson G. Org. Lett. 2009; 11: 503
    CrossrefPubMed
  • 14 Escudero J. Bellosta V. Cossy J. Angew. Chem. Int. Ed. 2018; 57: 574
    CrossrefPubMed
    • 15a Mendoza O. Rossey G. Ghosez L. Tetrahedron Lett. 2011; 52: 2235 ; and references therein
      Crossref
    • 15b Cossy J. Lutz F. Alauze V. Meyer C. Synlett 2002; 45
  • 16 Compound 9 was isolated as a mixture of E- and Z-isomers in a ratio 96:4.
  • 17 Spectral Data of (E)-9 IR: ν = 2923, 1640, 1446, 1373, 1335, 1210, 1089, 967, 910, 900 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.06 (s, 1 H), 7.60–7.50 (m, 2 H), 7.40–7.30 (m, 3 H), 5.85 (m, 1 H), 5.04 (dqapp, J = 17.0, 1.8 Hz, 1 H), 4.97 (m, 1 H), 4.32 (m, 1 H), 2.18 (m, 2 H), 1.83 (m, 1 H), 1.59 (m, 1 H), 1.30 (d, J = 6.2 Hz, 3 H). 13C NMR (100 MHz, CDCl3): δ = 145.2, 138.4, 130.8, 129.7, 128.4 (2 C), 126.9 (2 C), 114.6, 79.9, 34.8, 29.7, 19.2. MS (EI): m/z = 203 (13) [M+•], 202 (40), 188 (8), 158 (8), 132 (3), 122 (7), 121 (10), 120 (9), 104 (42), 94 (4), 89 (5), 82 (6), 78 (9), 77 (47), 67 (15), 65 (8), 55 (100), 51 (13).
  • 18 General Procedure for the Synthesis of Oxime Ethers from N-Tosyl Alkoxyamines In a round-bottom flask, a mixture of a solution of N-tosyl alkoxyamide (0.2 mmol, 1 equiv) in anhydrous CH2Cl2 (c = 0.25 M), aldehyde (2 equiv), and a solution of HNTf2 (0.1 equiv) in anhydrous CH2Cl2 was stirred at 40 °C for 18 h. The reaction mixture was cooled to r.t. and saturated aqueous Na2CO3 was added. The two phases were separated, and the aqueous layer was extracted four times with CH2Cl2. The combined organic layers were washed with brine, dried over MgSO4, filtered, and concentrated in vacuo. The crude product was purified by flash chromatography on silica gel (petroleum ether/ethyl acetate) to obtain the desired oxime ether.
  • 19 Spectroscopic Data for 17 1H NMR (400 MHz, CDCl3): δ = 8.02 (s, 1 H), 7.52–7.49 (m, 2 H), 6.90–6.70 (m, 2 H), 5.85 (m, 1 H), 5.04 (dqapp, J = 17.1, 1.8 Hz, 1 H), 4.96 (m, 1 H), 4.29 (m, 1 H), 3.82 (s, 3 H), 2.20–2.15 (m, 2 H), 1.81 (m, 1 H), 1.60 (m, 1 H), 1.29 (d, J = 6.2 Hz, 3 H). 13C NMR (100 MHz, CDCl3): δ = 160.7, 147.5, 138.5, 128.3 (2 C), 125.4, 114.5, 114.1 (2C), 78.7, 55.3, 34.9, 29.7, 19.8. MS (EI): m/z = 233 (22) [M+•], 232 (33), 218 (26), 188 (11), 174 (13), 162 (10), 151 (41), 150 (22), 147 (15), 146 (9), 136 (20), 135 (58), 134 (78), 108 (50), 107 (20), 92 (19), 91 (12), 77 (36), 67 (6), 55 (100), 51 (7). HRMS (ESI): m/z calcd for C14H20NO2 [M + H]+: 234.1489; found: 234.1485.
  • 20 Spectroscopic Data for (E)-18 IR: ν = 3077, 2969, 2936, 2838, 1607, 1572, 1504, 1463, 1438, 1418, 1372, 1311, 1283, 1270, 1208, 1159, 1120, 1107, 1068, 1034, 993, 965 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.37 (s, 1 H), 7.72 (d, J = 8.6 Hz, 1 H), 6.48 (dd, J = 8.6, 0.5 Hz, 1 H), 6.42 (d, J = 2.3 Hz, 1 H), 5.85 (m, 1 H), 5.03 (dqapp, J = 17.1, 1.8 Hz, 1 H), 4.95 (m, 1 H), 4.28 (m, 1 H), 3.82 (s, 3 H), 3.81 (s, 3 H), 2.17 (m, 2 H), 1.81 (m, 1 H), 1.60 (m, 1 H), 1.29 (d, J = 6.2 Hz, 3 H). 13C NMR (100 MHz, CDCl3): δ = 162.1, 158.7, 143.9, 138.6, 127.2, 114.4, 114.3, 105.3, 98.2, 78.5, 55.5, 55.4, 34.9, 29.7, 19.8. MS (EI) m/z: 263 (M+., 12), 204 (10), 192 (11), 177 (14), 166 (10), 164 (37), 163 (15), 150 (18), 149 (100), 137 (12), 134 (14), 122 (14), 121 (44), 120 (18), 107 (16), 92 (10), 91 (10), 79 (11), 77 (22), 67 (10), 55 (59). HRMS (ESI): m/z calcd for C15H22NO3 [M + H]+: 264.1594; found: 264.1591.
  • 21 Spectroscopic Data for 13 IR: ν = 3073, 2925, 1573, 1448, 1340, 1273, 1210, 1046, 944, 913 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.09 (s, 1 H), 7.60–7.55 (m, 2 H), 7.40–7.30 (m, 3 H), 5.87 (m, 1 H), 5.06–5.00 (m, 2 H), 4.04 (s, 2 H), 2.17 (dtapp, J = 7.5 Hz, 0.9 Hz, 2 H), 1.43 (m, 10 H). 13C NMR (100 MHz, CDCl3): δ = 147.7, 134.8, 132.5, 129.5, 128.6 (2 C), 126.8 (2 C), 117.3, 79.5, 40.1, 37.2, 32.7 (2 C), 26.2, 21.4 (2 C). MS (EI): m/z = 257 (14), 256 (36), 132 (5), 122 (62), 106 (100), 104 (58), 95 (30), 93 (12), 81 (64), 79 (20), 69 (13), 55 (30), 51 (13).