Synlett 2012; 23(11): 1670-1674
DOI: 10.1055/s-0031-1290398
letter
© Georg Thieme Verlag Stuttgart · New York

Palladium-Catalyzed Coupling of Pyrid-4-yl Nonaflates with Methyl Diazoacetate

Christian Eidamshaus
Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany, Fax: +49(30)83855367   Email: [email protected]
,
Paul Hommes
Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany, Fax: +49(30)83855367   Email: [email protected]
,
Hans-Ulrich Reissig*
Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany, Fax: +49(30)83855367   Email: [email protected]
› Author Affiliations
Further Information

Publication History

Received: 16 April 2012

Accepted: 03 May 2012

Publication Date:
14 June 2012 (online)


Abstract

Palladium-catalyzed couplings of pyrid-4-yl nonaflates with methyl diazoacetate are described. After optimization of the reaction conditions the scope of the transformation proved to be fairly broad and a series of pyrid-4-yl-substituted methyl diazoacetates was prepared in generally high yields.

Supporting Information

 
  • References and Notes

  • 1 Metal-Catalyzed Cross Coupling Reactions . 2nd ed.; Diederich F, de Meijere A. Wiley-VCH; Weinheim: 2004

    • Reviews:
    • 2a Culkin DA, Hartwig JF. Acc. Chem. Res. 2003; 36: 234
    • 2b For palladium-catalyzed arylations of amines and α-CH acidic compounds, see: Schlummer B, Scholz U. In Modern Arylation Methods . Ackermann L. Wiley-VCH; Weinheim: 2009: 69
    • 2c Colacot TJ, Johansson CC. C. Angew. Chem. Int. Ed. 2010; 49: 676 ; Angew. Chem. 2010, 122, 686; and references cited in these reviews
    • 2d For a very early case of an intramolecular coupling involving ketone enolates, see: Khan FA, Czerwonka R, Reissig H.-U. Synlett 1996; 533
  • 4 Peng C, Cheng J, Wang J. J. Am. Chem. Soc. 2007; 129: 8708
  • 5 Babinski DJ, Aguilar HR, Still R, Frantz DE. J. Org. Chem. 2011; 76: 5915 ; In this report, most of the prepared enol triflates are converted without purification into the diazo compounds, which then underwent an electrocyclic ring closure to provide pyrazole derivatives
    • 6a Lechel T, Dash J, Eidamshaus C, Brüdgam I, Lentz D, Reissig H.-U. Org. Biomol. Chem. 2010; 8: 3007
    • 6b For a review, see: Högermeier J, Reissig H.-U. Adv. Synth. Catal. 2009; 351: 2747
    • 7a Tomioka H, Ichikawa N, Komatsu K. J. Am. Chem. Soc. 1993; 115: 8621
    • 7b Sarkar TK, Gosh SK, Nandy SK, Chow TJ. Tetrahedron Lett. 1999; 40: 397
    • 7c Muchall HM, Werstiuk NH, Pitters JL, Workentin MS. Tetrahedron 1999; 55: 3767
    • 7d Sarkar TK, Ghosh SK, Chow TJ. J. Org. Chem. 2000; 65: 3111
    • 7e Davies HM. L, Townsend RJ. J. Org. Chem. 2001; 66: 6595
    • 7f Sarkar TK, Basak S, Slanina Z, Chow TJ. J. Org. Chem. 2003; 68: 4206
    • 8a Flögel O, Dash J, Brüdgam I, Hartl H, Reissig H.-U. Chem. Eur. J. 2004; 10: 4283
    • 8b For a review, see: Lechel T, Reissig H.-U. Pure Appl. Chem. 2010; 82: 1835
    • 9a Dash J, Lechel T, Reissig H.-U. Org. Lett. 2007; 9: 5541
    • 9b Lechel T, Dash J, Hommes P, Lentz D, Reissig H.-U. J. Org. Chem. 2010; 75: 726
    • 9c Bera MK, Hommes P, Reissig H.-U. Chem. Eur. J. 2011; 17: 11838
    • 10a Dash J, Reissig H.-U. Chem. Eur. J. 2009; 15: 6811
    • 10b Hommes P, Jungk P, Reissig H.-U. Synlett 2011; 2311
    • 11a Eidamshaus C, Reissig H.-U. Adv. Synth. Catal. 2009; 351: 1162
    • 11b Eidamshaus C, Kumar R, Bera MK, Reissig H.-U. Beilstein J. Org. Chem. 2011; 7: 962
    • 11c Eidamshaus C, Reissig H.-U. Eur. J. Org. Chem. 2011; 6056
  • 12 Eidamshaus C, Reissig H.-U. Tetrahedron: Asymmetry 2011; 22: 1644
  • 13 Palladium-Catalyzed Coupling of Pyrid-4-yl Nonaflates with Methyl Diazoacetate; Typical Procedure for 14a: A sealed tube equipped with a stirring bar was charged with Pd(PPh3)4 (40 mg, 0.034 mmol) and pyrid-4-yl nonaflate 13a 11c (210 mg, 0.34 mmol). MeCN (3.5 mL), Et3N (71 μL, 0.51 mmol) and methyl diazoacetate (100 mg, 1.00 mmol) were added and the resulting solution was stirred at 45 °C for 4 h until complete conversion of the starting material was observed (reaction monitored by TLC). H2O (20 mL) and EtOAc (20 mL) were added and the organic layer was separated. The aqueous layer was extracted with EtOAc (3 × 20 mL) and the combined organic layers were dried with Na2SO4, filtered, and the solvent was removed under reduced pressure. The crude product was purified by flash column chromatography on silica gel (hexane–EtOAc, 4:1) to provide pyridyl diazoacetate 14a (101 mg, 72%) as a yellow oil. [α]D –63.5 (c = 1.0, CHCl3). IR (ATR): 3090–2860 (C-H), 2095 (CN2), 1715 (C=O), 1595–1550 (C=C) cm–1. 1H NMR (500 MHz, CDCl3): δ = 0.00, 0.93 (2 × s, 6 H + 9 H, OTBS), 2.49 (s, 3 H, Me), 3.86 (s, 3 H, CO2CH3), 5.83 (s, 1 H, CHPh), 7.17–7.20, 7.25–7.29, 7.37–7.38, 7.47–7.49 (4 × m, 1 H + 3 H + 1 H + 2 H, Ph, 3-H/5-H). 13C NMR (126 MHz, CDCl3): δ = –4.93, –4.91, 18.2, 25.7 (2 × q + s + q, OTBS), 24.6 (q, Me), 52.1 (q, CO2 CH3), 77.5 (d, CHPh), 110.3, 115.5 (2 × d, C-3/C-5), 126.2, 127.0, 128.0 (3 × d, Ph), 128.2, 136.0, 143.7, 157.6 (4 × s, Ph, C-2/C-4/C-5), 164.3 (s, CO); the signal for C=N2 was not detected. HRMS (ESI-TOF): m/z [M + H]+ calcd. for C22H30N3O3Si: 412.2051; found: 412.2039
    • 14a Lyapkalo IM, Webel M, Reissig H.-U. Eur. J. Org. Chem. 2002; 1015
    • 14b Vogel MA. K, Stark CB. W, Lyapkalo IM. Synlett 2007; 2907
  • 16 Pitters JL, Adkinson DK, Griffiths K, Norton PR, Workentin MS. Can. J. Chem. 2010; 89: 117