PDF herunterladen
Synlett 2004(6): 975-978  
DOI: 10.1055/s-2004-820044
LETTER
© Georg Thieme Verlag Stuttgart · New York

Photochemical Ring Opening of Tricyclic Hemiketals: Diastereoselective Construction of Functionalized Medium-Sized Carbocycles and a Diquinane

Namakkal G. Ramesha, Alfred Hassner*b
a Department of Chemistry, Indian Institute of Technology - Delhi, Hauz Khas, New Delhi, 110 016, India
b Department of Chemistry, Bar-Ilan University, Ramat Gan, 52900, Israel
Fax: +972(3)5351250; e-Mail: hassna@mail.biu.ac.il;
Weitere Informationen

Publikationsverlauf

Received 31 December 2003
Publikationsdatum:
25. März 2004 (online)

    Lizenzen und Reprints Alle Artikel dieser Rubrik

Abstract

A facile stereoselective construction of functionalized medium-sized carbocycles and a diquinane from bicyclo[3.n.1]alkanones is reported. The key step is the hypervalent iodine mediated photochemical ring opening of tricyclic hemiketals, formed by dihydroxylation of methylene-bicyclo[3.3.1]nonan-9-one and methylene-bicyclo[3.2.1]octan-8-one, to afford eight- and seven-membered carbocyclic rings, respectively. Subsequent transformation of the cyclooctane into a diquinane was achieved using LDA. The reaction was also extended to the synthesis of a fused bicylic system.

Key words

medium-sized carbocycles - diquinane - radical reaction - bicyclic ketones - Suarez cleavage

    References

  • 1a Marco-Contelles J. De Opazo E. J. Org. Chem.  2002,  67:  3705 ; and references cited therein
    CrossrefGoogle Scholar
  • 1b Yet L. Tetrahedron  1999,  55:  9349 
    CrossrefGoogle Scholar
  • 1c Mehta G. Singh V. Chem. Rev.  1999,  99:  881 
    CrossrefGoogle Scholar
  • 1d Molander GA. Acc. Chem. Res.  1998,  31:  603 
    CrossrefGoogle Scholar
  • For some recent examples on the synthesis of medium-sized carbocycles:
  • 2a Fillion E. Beingessner RL. J. Org. Chem.  2003,  68:  9485 
    Google Scholar
  • 2b Oh H.-S. Cha JK. Tetrahedron: Asymmetry  2003,  14:  2911 
    Google Scholar
  • 2c Rassu G. Auzzas L. Pinna L. Zambrano V. Zanardi F. Battistini L. Gaetani E. Curti C. Casiraghi G. J. Org. Chem.  2003,  68:  5881 
    Google Scholar
  • 2d Rodriguez RJ. Castedo L. Mascarenas JL. Chem.-Eur. J.  2002,  8:  2923 
    Google Scholar
  • 2e Marco-Contelles J. De Opazo E. J. Carbohydr. Chem.  2002,  21:  201 
    Google Scholar
  • 2f Molander GA. Brown GA. De Gracia IS. J. Org. Chem.  2002,  67:  3459 
    Google Scholar
  • 2g Lopez L. Castedo L. Mascarenas JL. J. Am. Chem. Soc.  2002,  124:  4218 
    Google Scholar
  • 2h Denmark SE. Yang S.-M. J. Am. Chem. Soc.  2002,  124:  2102 ; and references cited therein
    Google Scholar
  • 3 Lee K. Cha JK. Tetrahedron Lett.  2001,  42:  6019 ; and references cited therein
    CrossrefGoogle Scholar
  • 4 Curran DP. Porter NA. Giese B. Stereochemistry of Radical Reactions: Concepts, Guidelines and Synthetic Applications   VCH; NY: 1996. 
    Google Scholar
  • 5 Ghera E. Ramesh NG. Laxer A. Hassner A. Tetrahedron Lett.  1995,  36:  1333 
    CrossrefGoogle Scholar
  • 6 Filippini M.-H. Rodriguez J. Chem. Rev.  1999,  99:  27 
    CrossrefGoogle Scholar
  • For some very recent papers on β-fragmentation of alkoxy radicals from the Suarez group:
  • 7a Francisco CG. Gonzalez CC. Kennedy AR. Paz NR. Suarez E. Tetrahedron: Asymmetry  2004,  15:  11 
    CrossrefGoogle Scholar
  • 7b Francisco CG. Gonzalez CC. Paz NR. Suarez E. Org. Lett.  2003,  5:  4171 
    CrossrefGoogle Scholar
  • 7c Alonso-Cruz CR. Kennedy AR. Rodriguez MS. Suarez E. Org. Lett.  2003,  5:  3729 
    CrossrefGoogle Scholar
  • 7d Gonzalez CC. Leon EI. Riesco-Fagundo C. Suarez E. Tetrahedron Lett.  2003,  44:  6347 
    CrossrefGoogle Scholar
  • 11 Markgraf JH. Staley SW. Allen JR. Synth. Commun.  1989,  19:  1471 
    Google Scholar
8

All new compounds were thoroughly characterized by IR, 1H NMR (including COSY and NOESY wherever required), 13C NMR and HRMS.

9

Typical Experimental Procedure for Photochemical Ring Cleavage: To a solution of protected hemi-ketal 6 (295 mg, 0.72 mmol) in anhyd cyclohexane (85 mL) under argon, were added PhI(OAc)2 (396 mg, 1.29 mmol) and I2 (312 mg, 1.29 mmol) at once and the resulting reaction mixture was irradiated with one 100 W tungsten filament lamp (internal temperature 43 °C) for 1 h, after which the reaction mixture was poured into a 1:1 mixture of Et2O and aq NaHSO3 solution. The organic layer was separated, washed with NaHSO3 solution, dried over anhyd MgSO4, filtered and concentrated. Column chromatography over silica gel using petroleum ether and EtOAc (9:1) afforded the two regiomers, 10 and 11, in a ratio of 5:1 in an overall yield of 61%.

10

Spectral data for selected compounds: Compound 10: Mp 142-143 °C. 1H NMR (300 MHz, CDCl3): δ = 4.87 (ddd, J = 9.5, 3.5, 1.0 Hz, 1 H), 3.61 (d, J = 11.0 Hz, 1 H), 3.38 (d, J = 11.0 Hz, 1 H), 3.05 (dt, J = 5.0, 3.5 Hz, 1 H), 2.91 (ddt, J = 11.5, 5.5, 2.5 Hz, 1 H), 2.83 (dd, J = 17.5, 3.5 Hz, 1 H), 2.73-2.58 (m, 2 H), 2.25 (dd, J = 17.5, 5.0 Hz, 1 H), 2.23-2.13 (m, 2 H), 1.89-1.77 (m, 2 H), 1.62-1.40 (m, 11 H, with t-butyl group superimposed), 0.86 (s, 9 H), 0.048 (s, 3 H), 0.044 (s, 3 H). 13C NMR (75 MHz): δ = 178.09, 170.86, 88.69, 81.24, 67.18, 47.46, 39.38, 36.18, 36.12, 35.73, 32.49, 28.06, 28.00, 27.87, 25.76, 18.13, -5.36, -5.50. HRMS: m/z [MH+] calcd for C22H40O5SiI: 539.168980; found: 539.168978. Compound 11: Viscous liquid. 1H NMR (300 MHz, CDCl3): δ = 4.47 (dddd, J = 12.0, 11.0, 3.5, 2.0 Hz, 1 H), 3.52 (d, J = 10.5 Hz, 1 H), 3.43 (d, J = 10.5 Hz, 1 H), 3.18 (td, J = 10.5, 5.0 Hz, 1 H), 3.08 (ddd, J = 10.5, 7.5, 1.5 Hz, 1 H), 2.83 (ddd, J = 16.0, 10.0, 2.0 Hz, 1 H), 2.72-2.46 (m, 2 H), 2.37 (dd, J = 15.0, 12.0 Hz, 1 H), 2.20-1.90 (m, 2 H), 1.79-1.58 (m, 3 H), 1.57-1.37 (m, 10 H,with t-butyl group superimposed), 0.89 (s, 9 H), 0.082 (s, 3 H), 0.068 (s, 3 H). 13C NMR (50 MHz, CDCl3): δ = 177.01, 170.16, 88.28, 81.48, 69.35, 45.35, 42.25, 41.33, 36.69, 34.15, 29.32, 28.03, 27.06, 25.78, 24.92, 18.17, -5.21. HRMS: m/z [MH+] calcd for C22H40O5SiI: 539.168980; found: 539.167411. Compound 12: Mp 101 °C. 1H NMR (300 MHz, CDCl3): δ = 3.88 (d, J = 11.5 Hz, 1 H), 3.82 (d, J = 11.5 Hz, 1 H), 2.73 (ddd, J = 10.5, 9.5, 5.0 Hz, 1 H), 2.62 (dd, J = 14.5, 5.0 Hz, 1 H), 2.46 (ddd, J = 10.5, 8.0, 6.0 Hz, 1 H), 2.20 (dd, J = 14.5, 9.5 Hz, 1 H), 2.17-2.10 (m, 1 H), 2.02-1.86 (m, 2 H), 1.82-1.60 (m, 4 H), 1.50-1.40 (m, 10 H with t-butyl group superimposed), 0.89 (s, 9 H), 0.09 (s, 3 H), 0.08 (s, 3 H). 13C NMR (75 MHz, CDCl3): δ = 178.42, 170.87, 94.04, 80.80, 61.79, 59.50, 49.20, 40.95, 40.27, 35.06, 28.03, 26.72, 26.26, 25.79, 22.62, 18.22, -5.37,
-5.49. MS (DCI, CH4): m/z (%) = 355 (100) [MH+ - 56], 297 (35), 157 (44). HRMS: m/z [MH+ -56, McLafferty] calcd for C 18H31O5Si: 355.194078; found: 355.186503. Compound 19: Viscous liquid. 1H NMR (300 MHz, CDCl3): δ = 5.28 (dd, J = 3.5, 2.0 Hz, 1 H), 3.65 (d, J = 11.5 Hz, 1 H), 3.38 (d, J = 11.5 Hz, 1 H), 3.30 (dt, J = 8.5, 2.0 Hz, 1 H), 2.98 (dtd, J = 13.5, 5.0, 2.5 Hz, 1 H), 2.70-2.59 (m, 2 H), 2.29 (dd, J = 17.0, 8.5 Hz, 1 H), 2.07 (dd, J = 15.5, 5.0 Hz, 1 H), 2.02 (dd, J = 14.0, 2.5 Hz, 1 H), 1.66 (dd, J =1 5.5, 5.0 Hz, 1 H), 1.68-1.60 (m, 3 H), 1.48 (s, 9 H), 1.47-1.10 (m, 5 H), 1.05 (s, 3 H), 0.86 (s, 9 H), 0.04 (s, 6 H). 13C NMR (75 MHz, CDCl3): δ = 178.90, 170.72, 90.02, 81.42, 65.39, 53.46, 46.00, 44.79, 43.47, 40.88, 38.89, 38.58, 38.44, 32.81, 28.05, 27.33, 27.28, 25.79, 20.78, 20.53, 18.20, -5.26, -5.42. MS: m/z = 665 (20) [MH+], 607 (22), 492 (100), 423 (55), 365 (46), 245 (25).