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Synlett 2002(6): 0942-0946
DOI: 10.1055/s-2002-31894
LETTER
© Georg Thieme Verlag Stuttgart · New York

VO(acac)2/TBHP Catalyzed Epoxidation of 2-(2-Alkenyl)phenols. Highly Regio- and Diastereoselective Oxidative Cyclization to 2,3-Dihydro-benzofuranols and 3-Chromanols

Alessandra Lattanzi*, Arrigo Scettri
Dipartimento di Chimica, Università di Salerno, Via S. Allende, I-84081 Baronissi (Salerno), Italy
Fax: +39(89)965296; e-Mail: lattanzi@unisa.it;
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Publication History

Received 4 March 2002
Publication Date:
07 February 2007 (online)

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Abstract

The VO(acac)2/TBHP (1.5 mol%/1.3 equiv) system has been successfully used for the epoxidation of variously double bond substituted 2-(2-alkenyl)phenols under mild conditions. Moreover, a one-pot conversion to 2,3-dihydrobenzofuranols and 3-chromanols is achieved with high or complete regio- and diastereoselectivity in the presence of catalytic amounts of TFA (20 mol%). This metal-catalyzed methodology was shown to be more practical and superior to the previously employed m-CPBA for the epoxidation and the oxidative cyclization of 2-(2-alkenyl)phenols.

Key words

epoxidation - regio- and diastereoselectivity - 2-(2-alkenyl)phenols - oxidative cyclization - vanadium

    References

  • 1a Finn MG. Sharpless KB. In Asymmetric Synthesis   Morrison JD. Academic Press; New York: 1985.  p.247 
    Google Scholar
  • 1b Rossiter BE. In Asymmetric Synthesis   Morrison JD. Academic Press; New York: 1985.  p.193 
    Google Scholar
  • 2a Sharpless KB. Michaelson RC. J. Am. Chem. Soc.  1973,  95:  6136 
    CrossrefGoogle Scholar
  • 2b Sharpless KB. Verhoeven TR. Aldrichimica Acta  1979,  12:  63 
    CrossrefGoogle Scholar
  • 2c Itoh T. Jitsukawa K. Kaneda K. Teranishi S. J. Am. Chem. Soc.  1979,  101:  159 
    CrossrefGoogle Scholar
  • 3 Mihelich ED. Daniels K. Eickhoff D. J. Am. Chem. Soc.  1981,  103:  7690 
    CrossrefGoogle Scholar
  • 4a Della Sala G. Giordano L. Lattanzi A. Proto A. Scettri A. Tetrahedron  2000,  56:  3567 
    Article in Thieme ConnectGoogle Scholar
  • 4b Lattanzi A. Della Sala G. Russo M. Scettri A. Synlett  2001,  1479 
    Article in Thieme ConnectGoogle Scholar
  • 5a De Bernardi M. Vidari G. Vita Finzi P.. Tetrahedron  1992,  48:  7331 
    Article in Thieme ConnectGoogle Scholar
  • 5b David M. Sauleau J. Sauleau A. Bull. Soc. Chim. Fr.  1993,  130:  527 
    Article in Thieme ConnectGoogle Scholar
  • 5c Bouzbouz S. Kirschleger B. Synthesis  1994,  714 
    Article in Thieme ConnectGoogle Scholar
  • 6 Murray RDH. Sutchliffe M. McCabe PH. Tetrahedron  1971,  27:  4901 
    CrossrefGoogle Scholar
  • 7 Blunt SB. Chen T.-B. Wiemer DF. J. Nat. Prod.  1998,  61:  1400 
    CrossrefGoogle Scholar
  • 8 Hosokawa T. Kono T. Shinohara T. Murahashi S.-I. J. Organomet. Chem.  1989,  370:  C13 
    CrossrefGoogle Scholar
  • 9a Nakata T. Schimd G. Vranesic B. Okigawa M. Smith-Palmer T. Kishi Y. J. Am. Chem. Soc.  1978,  100:  2933 
    Google Scholar
  • 9b Hanessian S. Cooke NG. DeHoff B. Sakito Y. J. Am. Chem. Soc.  1990,  112:  5276 
    Google Scholar
  • 9c Hashimoto M. Harigaya H. Yanagiya M. Shirahama H. J. Org. Chem.  1991,  56:  2299 
    Google Scholar
  • 10 Compounds 1 were synthesized according to: Barluenga J. Sanz R. Fananas F. Tetrahedron Lett.  1997,  38:  6103 
    CrossrefGoogle Scholar
  • 13 Michelson RC. Palermo RE. Sharpless KB. J. Am. Chem. Soc.  1977,  99:  1990 
    CrossrefGoogle Scholar
  • 14 Baldwin JE. J. Chem. Soc., Chem. Commun.  1976,  734 
    CrossrefGoogle Scholar
  • 15a Ishii H. Ishikawa T. Tetrahedron Lett.  1982,  23:  4245 
    CrossrefGoogle Scholar
  • 15b Xu X. de Guzman FS. Gloer JB. Shesrer CA. J. Org. Chem.  1992,  57:  6700 
    CrossrefGoogle Scholar
  • 15c Nozawa Y. Yamamoto K. Ito M. Sakai N. Mizoue K. Mizobe F. Hanada K. J. Antibiot.  1997,  50:  635 
    CrossrefGoogle Scholar
  • 15d Ramadas S. Krupadanam GLD. Tetrahedron: Asymmetry  2000,  11:  3375 
    CrossrefGoogle Scholar
  • 16a The typical experimental procedure and work up for the oxidative cyclization is the same as reported for the epoxidation of 1, with the exception that TFA (15 µL, 0.20 mmol) was added after TBHP. Spectroscopic data for compound 3a matched with the literature: Ramadas S. Krupadanam LD. Tetrahedron: Asymmetry  2000,  11:  3375 
    Google Scholar
  • 16b

    3b was obtained as inseparable erythro/threo 85:15 mixture of diastereisomers. 1H NMR (400 MHz, CDCl3): δ (erythro-isomer, distinct signals) = 1.22 (3 H, d, J = 6.4 Hz), 1.92 (1 H, br s), 3.11 (1 H, dd, J = 15.5, 9.3 Hz), 4.17 (1 H, dq, J = 6.4, 3.4 Hz), 4.70 (1 H, dq, J = 8.8, 3.4 Hz). δ (threo-isomer, distinct signals) = 1.27 (3 H, d, J = 6.4 Hz), 2.38 (1 H, br s), 2.96, (1 H, dd, J = 15.6, 7.8 Hz), 3.84 (1 H, quint, J = 6.6 Hz), 4.56 (1 H, q, J = 9.2 Hz). Over-lapped signals δ = 3.23 (1 H, dd, J = 15.5, 8.4 Hz erythro;
    1 H, threo), 6.76-6.79 (1 H, erythro; 1 H, threo, m), 6.83-6.86 (1 H, erythro; 1 H, threo, m), 7.08-7.12 (1 H, erythro; 1 H, threo, m), 7.16-7.18 (1 H, erythro; 1 H, threo, m). 13C NMR (100 MHz, CDCl3): δ = 17.6, 18.2, 29.2, 31.8, 68.1, 69.9, 109.0, 109.3, 120.5, 124.8, 124.9, 126.8, 127.7, 127.9, 159.3. IR (KBr): 750, 860, 898, 1233, 1462, 1481, 2931, 2973, 3351 cm-1. MS: m/z (%) = 164(76) [M+], 146(38), 131(100), 119(34), 107(20), 91(80). Anal. Calcd for C10H12O2: C, 73.15; H, 7.37. Found: C, 73.33; H, 7.26. 3c: 1H NMR (400 MHz, CDCl3): δ = 2.93 (1 H, dd, J = 16.0, 8.9 Hz), 3.10 (1 H, dd, J = 16.0, 5.3 Hz), 4.12-4.17 (1 H, m), 4.82 (1 H, d, J = 7.9 Hz), 6.91-6.95 (2 H, m), 7.09-7.47 (7 H, m). 13C NMR (100 MHz, CDCl3): δ = 32.7, 68.1, 81.8, 116.4, 120.0, 121.0, 127.0, 127.6, 128.6, 128.7, 129.9, 138.1, 153.9. IR (KBr): 700, 752, 1242, 1457, 1487, 2923, 3388 cm-1. MS: m/z (%) = 226(24) [M+], 210(42), 134(50), 120(37), 107(100), 91(89), 77(38). Anal. Calcd for C15H14O2: C, 79.62; H, 6.24. Found: C, 79.46; H, 6.11. 3d: 1H NMR (400 MHz, CDCl3): δ = 1.44 (3 H, s), 2.40 (1 H, bs), 2.90 (1 H, AB, J = 15.5 Hz), 3.25 (1 H, AB, J = 15.5 Hz), 3.63 (1 H, AB, J = 11.7 Hz), 3.68 (1 H, AB, J = 11.7 Hz), 6.74-6.76 (1 H, m), 6.82-6.87 (1 H, m), 7.09-7.11 (1 H, m), 7.13-7.16 (1 H, m). 13C NMR (100 MHz, CDCl3): δ = 23.1, 37.7, 68.2, 88.5, 109.4, 120.3, 125.1, 126.7, 127.9, 158.5. IR (KBr): 748, 883, 1241, 1459, 1480, 2924, 3420 cm-1. MS: m/z (%) = 164(62) [M+], 146(27), 133(100), 119(24), 105(71), 91(59). Anal. Calcd for C10H12O2: C, 73.15; H, 7.37. Found: C, 73.31; H, 7.29. 4e: 1H NMR (400 MHz, CDCl3): δ = 1.31 (3 H, s), 1.36 (3 H, s), 1.85 (1 H, bs), 2.77 (1 H, dd, J = 16.7, 5.5 Hz), 3.06 (1 H, dd, J = 16.7, 5.5 Hz), 3.80 (1 H, t, J = 5.1 Hz), 6.80-6.90 (2 H, m), 7.05-7.16 (2 H, m). 13C NMR (100 MHz, CDCl3): δ = 22.2, 24.7, 31.3, 69.7, 89.2, 117.2, 118.8, 120.5, 127.6, 130.0, 152.7. IR (KBr): 752, 854, 1257, 1456, 1487, 2923, 3342 cm-1. MS: m/z (%) = 178(82) [M+], 161(23), 145(65), 120(73), 107(100), 91(80), 77(28). Anal. Calcd for C11H14O2: C, 74.13; H, 7.92. Found: C, 74.35; H, 7.83.

    Google Scholar
  • 16c Spectroscopic data for compounds 3e matched with the literature: Hosokawa T. Imada Y. Murahashi S.-I. Bull. Chem. Soc. Jpn.  1985,  58:  3282 
    Google Scholar
  • 16d

    Spectroscopic data for 4f: 1H NMR (400 MHz, CDCl3): δ = 1.34 (3 H, s), 1.60 (3 H, s), 1.67 (3 H, s), 1.50-1.60 (2 H, m), 1.95 (1 H, bs), 2.15 (2 H, m), 2.78 (1 H, dd, J = 16.7, 5.8 Hz), 3.05 (1 H, dd, J = 16.7, 4.9 Hz), 3.86-3.89 (1 H, m), 5.07-5.11 (1 H, m), 6.75-6.95 (2 H, m), 7.03-7.20 (2 H, m). 13C NMR (100 MHz, CDCl3): δ = 17.5, 19.3, 21.6, 25.6, 31.1, 37.0, 68.1, 78.5, 117.2, 118.9, 120.5, 123.9, 127.6, 129.9, 131.9, 152.8. IR (KBr): 753, 855, 1257, 1456, 1487, 2924, 3400 cm-1. MS: m/z (%) = 246(58) [M+], 229(20), 194(96), 161(34), 145(39), 107(100), 91(41). Anal. Calcd for C16H22O2: C, 78.01; H, 9.00. Found: C, 78.20; H, 9.11. 3f: 1H NMR (400 MHz, CDCl3): δ = 1.31 (3 H, s), 1.60-1.50 (2 H, m), 1.63 (3 H, s), 1.69 (3 H, s), 1.87 (1 H, bs), 2.10-2.16 (2 H, m), 3.09 (1 H, dd, J = 15.7, 9.5 Hz), 3.22 (1 H, dd, J = 15.7, 8.9 Hz), 4.63 (1 H, t, J = 9.3), 5.08-5.14 (1 H, m), 6.70-6.90 (2 H, m), 7.05-7.18 (2 H, m). 13C NMR (100 MHz, CDCl3): δ = 17.6, 21.9, 23.0, 25.7, 30.3, 36.9, 73.5, 88.7, 109.1, 120.5, 124.2, 124.9, 127.1, 127.8, 132.0, 159.5. IR (KBr): 749, 872, 1238, 1445, 1480, 2928, 3405 cm-1. Anal. Calcd for C16H22O2: C, 78.01; H, 9.00. Found: C, 78.29; H, 9.18.

    Google Scholar
  • 21 Porter LJ. In The Flavonoids, Advances in Research Since 1980   Harborne JB. Chapman and Hall; London: 1994.  p.23 
    Google Scholar
  • 22 Weinges K. Annalen  1958,  615:  203 
    Google Scholar
  • 23 van Rensburg H. van Heerden PS. Ferreira D. J. Chem. Soc., Perkin Trans. 1  1997,  3415 
    CrossrefGoogle Scholar
  • 24 Inoue S. Asami M. Honda K. Shrestha KS. Takahashi M. Yoshino T. Synlett  1998,  679 
    Article in Thieme ConnectGoogle Scholar
11

Typical Experimental Procedure for the Epoxidation: To a stirred solution of anhyd CH2Cl2 (8 mL), under an argon atmosphere, were added VO(acac)2 (3.9 mg, 0.015 mmol) and 1 (1 mmol); then after 5 min TBHP (230 µL, 1.3 mmol of 5.5 M decane solution) was added. Upon completion, after monitoring on TLC using PE/Et2O mixtures, the solvent of the crude reaction mixture was partially removed in vacuo and then the concentrated crude mixture was filtered through a small pad of silica gel before 1H NMR analysis. The reaction mixture was purified by flash chromatography (PE/Et2O) to give the desired epoxides 2. 2a: 1H NMR (400 MHz, CDCl3): δ = 2.68-2.74 (2 H, m), 2.93 (1 H, t, J = 4.0 Hz), 3.22 (1 H, dd, J = 5.0, 2.4 Hz), 3.27-3.32 (1 H, m), 6.80-6.92 (2 H, m), 6.97 (1 H, s), 7.08-7.11 (1 H, m), 7.15-7.19 (1 H, m). 13C NMR (100 MHz, CDCl3): δ = 34.5, 48.0, 53.4, 116.8, 120.5, 123.1, 128.6, 130.9, 155.3. IR (KBr): 753, 848, 825, 1234, 1456, 1594, 2925, 3330 cm-1. MS: m/z (%) = 150(72) [M+], 131(100), 119(40), 91(97), 77(16). Anal. Calcd for C9H10O2: C, 71.98; H, 6.71. Found: C, 71.80; H, 6.66. 2b was obtained as inseparable (trans/cis 85:15) mixture of diastereoisomers. 1H NMR (400 MHz, CDCl3): δ (trans-isomer, distinct signals) = 1.33 (3 H, d, J = 4.9 Hz), 2.73 (1 H, dd, J = 14.9, 7.0 Hz), 3.17 (1 H, dd, J = 14.9, 2.0 Hz). δ (cis-isomer, distinct signals) = 1.49 (3 H, d, J = 5.4 Hz), 2.85 (1 H, dd, J = 9.3, 4.9 Hz), 2.91 (1 H, dd, J = 14.9, 3.2 Hz), 3.30 (1 H, quint, J = 5.4 Hz). Overlapped signals δ = 3.00-3.06 (2 H, trans; 1 H cis, m), 6.83-6.88 (1 H, trans; 1 H, cis, m), 6.90-6.92 (1 H, trans; 1 H, cis, m), 7.06-7.09 (1 H, trans; 1 H, cis, m), 7.14-7.16 (1 H, trans; 1 H, cis, m). 13C NMR (100 MHz, CDCl3): δ = 17.0, 17.5, 34.4, 56.1, 60.8, 68.1, 86.3, 109.0, 117.0, 120.4, 120.5, 123.4, 124.9, 127.8, 128.6, 130.8, 155.5. IR (KBr): 752, 842, 830, 1233, 1457, 1595, 2923, 3330 cm-1. MS: m/z (%) = 164(69) [M+], 146(30), 131(100), 119(29), 107(27), 91(73), 77(13). Anal. Calcd for C10H12O2: C, 73.15; H, 7.37. Found: C, 72.88; H, 7.46. 2c: 1H NMR (400 MHz, CDCl3): δ = 2.90 (1 H, dd, J = 14.9, 7.2 Hz), 3.29 (1 H, dd, J = 14.9, 2.0 Hz), 3.32-3.37 (1 H, m), 3.86 (1 H, d, J = 2.0 Hz), 6.60-6.69 (3 H, m), 7.10-7.39 (6 H, m). 13C NMR (100 MHz, CDCl3): δ = 34.6, 59.5, 63.6, 117.0, 120.7, 123.1, 125.7, 127.6, 128.5, 128.8, 131.0, 136.0, 155.4. IR (KBr): 698, 752, 1240, 1457, 1487, 2923, 3420 cm-1.
MS: m/z (%) = 226(16) [M+], 210(26), 134(58), 120(42), 107(100), 91(86), 77(34). Anal. Calcd for C15H14O2:
C, 79.62; H, 6.24. Found: C, 79.79; H, 6.32. 2d: 1H NMR (400 MHz, CDCl3): δ = 1.33 (3 H, s), 2.73 (1 H, AB, J = 15.0 Hz), 2.84 (1 H, AB, J = 4.1 Hz), 2.90 (1 H, AB, J = 4.1 Hz), 3.31 (1 H, AB, J = 15.0 Hz), 6.83-6.87 (1 H, m), 6.92-6.94 (1 H, m), 7.03-7.06 (1 H, m), 7.15-7.19 (1 H, m), 7.55 (1 H, s). 13C NMR (100 MHz, CDCl3): δ = 20.1, 39.4, 55.5, 59.5, 117.3, 120.3, 122.9, 128.8, 131.5, 155.7. IR (KBr): 747, 861, 884, 1241, 1459, 1481, 2923, 3336 cm-1. MS: m/z (%) = 164(90) [M+], 146(30), 131(100), 119(35), 105(68), 91(87), 77(28). Anal. Calcd for C10H12O2: C, 73.15; H, 7.37. Found: C, 73.29; H, 7.45. 2e: 1H NMR (400 MHz, CDCl3): δ = 1.33 (3 H, s), 1.35 (3 H, s), 2.82 (1 H, J = 14.7, 9.8 Hz), 2.94 (1 H, dd, J = 14.7, 2.7 Hz), 3.04 (1 H, dd, J = 9.8, 2.7 Hz), 6.84-6.86 (1 H, m), 6.92-6.93 (1 H, m), 7.01 (1 H, s), 7.10-7.12 (1 H, m), 7.15-7.17 (1 H, m). 13C NMR (100 MHz, CDCl3): δ = 18.8, 24.6, 31.6, 61.0, 65.3, 116.9, 120.5, 124.8, 128.5, 130.6, 155.4. IR (KBr): 751, 870, 861, 1233, 1457, 1481, 2924, 3490 cm-1. MS: m/z (%) = 178(100) [M+], 161(49), 145(54), 120(32), 107(43), 91(48). Anal. Calcd for C11H14O2: C, 74.13; H, 7.92. Found: C, 73.95; H, 7.81. 2f: 1H NMR (400 MHz, CDCl3): δ = 1.49 (3 H, s), 1.61 (3 H, s), 1.68 (3 H, s), 1.60-1.70 (2 H, m), 2.06-2.11 (2 H, m), 2.84 (1 H, dd, J = 14.6, 9.4 Hz), 2.90 (1 H, dd, J = 14.6, 3.3 Hz), 3.04 (1 H, dd, J = 9.4, 3.3 Hz), 5.03-5.08 (1 H, m), 6.84-6.86 (1 H, m), 6.91-6.93 (1 H, m), 7.06 (1 H, s), 7.10-7.12 (1 H, m), 7.15-7.17 (1 H, m). 13C NMR (100 MHz, CDCl3): δ = 16.7, 17.6, 23.5, 25.6, 31.6, 38.4, 63.4, 64.5, 117.0, 120.5, 123.1, 124.3, 128.5, 130.6, 132.2, 155.5. IR (KBr): 751, 860, 855, 1233, 1456, 1479, 2923, 3325 cm-1. MS: m/z (%) = 246(64) [M+], 178(58), 145(40), 133(100), 107(56), 95(58), 91(42), 77(20). Anal. Calcd for C16H22O2: C, 78.01; H, 9.00. Found: C, 78.20; H, 8.89.

12

From 1H NMR analysis of the crude mixture a complete conversion of 1c was observed; partial decomposition of the final product during silica gel chromatography may be responsible of the lower isolated yield.

17

The 2S*,3R* configuration was determined on the corresponding acetylated 4c by comparison with 1H NMR data reported in ref. [23]

18

The 2S*,3R* configuration was determined by comparison with 1H NMR data reported in ref. [24]

19

The erythro/threo ratio was determined by comparison with 1H NMR data reported in ref. [8]

20

It is interesting to note that in the oxidative cyclization of bishomoallylic alcohols using VO(acac)2/TBHP/HOAc, the regioselective formation of tetrahydrofuranols through a 5-exo ring closure of the intermediate epoxides was observed, without loss of the stereoselectivity obtained in the epoxidation step. Although the formation of 6-endo products, tetrahydropyranols, had been possible via more stable tertiary carbocations, these compounds were not isolated. The authors invoked steric factors to justify the experimental results. See ref. [9c]