Synthesis of (tetrahydrofuranyl)tetrahydrofurans via radical cyclization of bis(β-alkoxyacrylates)

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Eun Lee, Ho Young Song and Hee Jo Kim


Abstract

Radical cyclizations of bis(β-alkoxyacrylates) obtained from (3R,4R)- and meso-1,6-dibromohexane-3,4-diol proceed to form a C2-symmetric and a meso (tetrahydrofuranyl)tetrahydrofuran derivative.


References

  1. (a) E. Lee, J. S. Tae, C. Lee and C. M. Park, Tetrahedron Lett., 1993, 34, 4831 CrossRef CAS; (b) E. Lee, J. S. Tae, Y. H. Chong, Y. C. Park, M. Yun and S. Kim, Tetrahedron Lett., 1994, 35, 129 CrossRef CAS; (c) E. Lee and C. M. Park, J. Chem. Soc., Chem. Commun., 1994, 293 RSC; (d) E. Lee, J.-w. Jeong and Y. Yu, Tetrahedron Lett., 1997, 38, 7765 CrossRef CAS; (e) E. Lee, C. M. Park and J. S. Yun, J. Am. Chem. Soc., 1995, 117, 8017 CrossRef CAS; (f) E. Lee, S.-K. Yoo, Y.-S. Cho, H.-S. Cheon and Y. H. Chong, Tetrahedron Lett., 1997, 38, 7757 CrossRef CAS.
  2. In this case, a small amount of the minor product 4 was also obtained.
  3. E. Lee, S.-K. Yoo, H. Choo and H. Y. Song, Tetrahedron Lett., 1998, 39, 317 CrossRef CAS.
  4. 1H-NMR (300 MHz, CDCl3)δ 1.28 (d, 3H, J= 6.5 Hz), 1.90–1.95 (m, 1H), 2.17–2.19 (dd, 1H, J= 5.4, 1.6 Hz), 2.55 and 2.68 (AB of ABX, JAB= 15.6 Hz, JAX= 6.7 Hz, JBX= 6.1 Hz), 3.70 (s, 6H), 4.06–4.09 (m, 1H), 4.40 (m, 1H), 4.50 (m, 1H), 5.17 (d, 1H, J= 12.7 Hz), 7.51 (d, 1H, J= 12.7 Hz); 13C-NMR (75 MHz, CDCl3)δ 19.69, 37.54, 39.98, 51.18, 51.78, 74.33, 79.83, 86.18, 97.81, 160.70, 167.87, 171.06; MS (EI, relative intensity) 258 (M+, 3), 157 (86), 83 (100).
  5. 1H-NMR (300 MHz, CDCl3)δ 1.56–1.66 (m, 2H), 1.73–1.83 (m, 2H), 1.91–2.11 (m, 4H), 2.47 and 2.61 (AB of ABX, JAB= 15.2 Hz, JAX= 6.9 Hz, JBX= 6.4 Hz), 3.68 (s, 6H), 3.80–3.86 (m, 2H), 4.24–4.33 (m, 2H); 13C-NMR (75 MHz, CDCl3)δ 27.59, 30.79, 40.68, 51.55, 75.70, 81.34, 171.63; MS (CI, relative intensity) 287 (M+1, 100), 255 (26), 213 (20); HRMS (CI) calcd for C14H23O6 287.1495, found 287.1493.
  6. A trace amount of a minor (presumably epimeric) product was obtained.
  7. Sharpless asymmetric dihydroxylation of trans-1,6-dibromohex-3-ene, obtained from trans-hex-3-ene-1,6-diol via mesylation and bromide substitution, provided 74% yield of (3R,4R)-1,6-dibromohexane-3,4-diol in high enantiomeric excess (>98%). Reaction of this diol with ethyl propiolate was a little sluggish, and gave 40% yield of the corresponding bis(β-alkoxyacrylate). Radical cyclization produced ethyl ester analogues of 16 and 17 in 72% and 6% yield, respectively.
  8. [a]28D–8.9 (c 1.8, CHCl3); 1H-NMR (300 MHz, CDCl3)δ 1.56–1.78 (m, 4H), 1.86–1.96 (m, 2H), 2.01–2.12 (m, 2H), 2.47 and 2.73 (AB of ABX, JAB= 15.4 Hz, JAX= 6.3 Hz, JBX= 7.2 Hz), 3.68 (s, 6H), 3.80–3.87 (m, 2H), 4.25–4.34 (m, 2H); 13C-NMR (75 MHz, CDCl3)δ 27.59, 30.94, 40.48, 51.50, 75.78, 81.55, 171.68; MS (CI, relative intensity) 287 (M + 1, 100), 255 (86), 213 (21); HRMS (CI) calcd for C14H23O6 287.1495, found 287.1499.
  9. [a]26D–14.9 (c 0.62, CHCl3); 1H-NMR (300 MHz, CDCl3)δ 1.32–1.44 (m, 2H), 1.54–1.71 (m, 4H), 1.84–1.94 (m, 2H), 2.41 and 2.58 (AB of ABX, JAB= 15.3 Hz, JAX= 7.3 Hz, JBX= 5.7 Hz), 3.39 (br, 2H), 3.71 (s, 6H), 3.74–3.85 (m, 2H); 13C-NMR (75 MHz, CDCl3)δ 25.69, 29.17, 41.29, 51.56, 71.34, 73.82, 171.97; MS (CI, relative intensity) 287 (M + 1, 77), 255 (100), 213 (34); HRMS (CI) calcd for C14H23O6 287.1495, found 287.1491.
  10. (a) U. Koert, Synthesis, 1995, 115 CrossRef CAS; (b) Many of the more recent references on the synthesis of Annonaceous acetogenins may be found in A. Sinha, S. C. Sinha, S. C. Sinha and E. Keinan, J. Org. Chem., 1999, 64, 2381 Search PubMed.
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