B. C. Ranu, T. Mandal / Tetrahedron Letters 47 (2006) 2859–2861
2861
(c) Yorimitsu, H.; Shinokubo, H.; Oshima, K. Synlett
2002, 674.
hydrofuran-3-carboxylic acid ethyl ester (197 mg, 75%) as
a colorless liquid. IR (neat) 1514, 1604, 1732 cmÀ1 1H
;
2. (a) Motherwell, W. B.; Crich, D. Free Radical Chain
Reactions in Organic Synthesis; Academic: London, 1991;
(b) Jasperse, C. P.; Curran, D. P.; Fevig, T. L. Chem. Rev.
1991, 91, 1237.
3. (a) Curran, D. P.; Totleben, M. J. J. Am. Chem. Soc. 1992,
114, 6050; (b) Inoue, A.; Shinokubo, H.; Oshima, K. Org.
Lett. 2000, 2, 651; (c) Gansauer, A. Synlett 1998, 801; (d)
Yamazaki, O.; Yamaguchi, K.; Yokoyama, M.; Togo, H.
J. Org. Chem. 2000, 65, 5440; (e) Studer, A.; Amrein, S.
Angew. Chem., Int. Ed. 2000, 39, 3080.
4. (a) Cintas, P. Synlett 1995, 1087; (b) Li, C.-J. Tetrahedron
1996, 52, 5643; (c) Li, C.-J.; Chan, T. H. Tetrahedron 1999,
55, 11149; (d) Chauhan, K. K.; Frost, C. G. J. Chem. Soc.,
Perkin Trans. 1 2000, 3015; (e) Ranu, B. C. Eur. J. Org.
Chem. 2000, 2347; (f) Babu, G.; Perumal, P. T. Aldrichim.
Acta 2000, 33, 16; (g) Podelech, J.; Maier, T. C. Synthesis
2003, 633; (h) Nair, V.; Ros, S.; Jayan, C. N.; Pillai, B. S.
Tetrahedron 2004, 68, 1959.
NMR (CDCl3, 300 MHz): d 1.26 (t, J = 2.88 Hz, 3H), 3.79
(s, 3H), 4.12–4.26 (m, 2H), 4.45–4.64 (m, 3H), 5.08–5.19
(m, 3H), 6.87 (d, J = 8.79 Hz, 2H), 7.30 (d, J = 8.79 Hz,
2H); 13C NMR (CDCl3, 75 MHz): d 14.2, 55.3, 57.0, 61.1,
71.5, 83.2, 106.2, 113.9 (2C), 127.5 (2C), 129.7, 146.6,
159.5, 170.7. Anal. Calcd for C15H18O4: C, 68.68; H, 6.92.
Found: C, 68.54; H, 6.91. This procedure was followed for
reactions of all the substrates listed in Table 1. The
products (entries 1, 3, and 5–8), which are known12 were
identified by comparison of their spectroscopic data (IR,
1H NMR, and 13C NMR) with those reported. New
compounds (entries 2, 4, and 9–11) were characterized
from their spectroscopic data and elemental analysis.
These data are presented below:
1-(2-Benzo[1,3]dioxol-5-yl)-4-methylene-tetrahydrofuran-
3-yl-ethanone (entry 4). Colorless liquid; IR (neat): 1504,
1
1605, 1713 cmÀ1; H NMR (CDCl3, 300 MHz): d 2.24 (s,
3H), 3.61–3.64 (m, 1H), 4.44–4.61 (m, 2H), 5.08–5.18 (m,
3H), 5.95 (s, 2H), 6.77–6.83 (m, 3H); 13C NMR (CDCl3,
75 MHz): d 29.0, 65.3, 71.4, 82.8, 100.9, 106.2, 107.1,
108.0, 119.4, 134.2, 146.5, 147.3, 147.8, 205.1. Anal. Calcd
for C14H14O4: C, 68.28; H, 5.73. Found: C, 68.34; H, 5.62.
1-[2-(4-Benzyloxy-3-methoxy-phenyl)-4-methylene-tetra-
hydrofuran-3-yl] ethanone (entry 9). Yellowish gummy
5. Bhatti, N. H.; Salter, M. M. Tetrahedron Lett. 2004, 45,
8379.
6. Yanada, R.; Koh, Y.; Nishimori, N.; Matsumura, A.;
Obika, S.; Mitsuya, H.; Fuji, N.; Takemoto, Y. J. Org.
Chem. 2004, 69, 2417.
7. Inoue, K.; Sawada, A.; Shibata, I.; Baba, A. J. Am. Chem.
Soc. 2002, 124, 906.
;
liquid; IR (neat): 1514, 1593, 1711 cmÀ1 1H NMR
8. (a) Ranu, B. C.; Hajra, A.; Jana, U. J. Org. Chem. 2000,
65, 6270; (b) Ranu, B. C.; Hajra, A.; Jana, U. Tetrahedron
Lett. 2000, 41, 531; (c) Ranu, B. C.; Samanta, S.; Hajra, A.
Synlett 2002, 987; (d) Ranu, B. C.; Das, A.; Samanta, S.
Synlett 2002, 727; (e) Ranu, B. C.; Dey, S. S.; Hajra, A.
Tetrahedron 2002, 58, 2529; (f) Ranu, B. C.; Hajra, A.;
Dey, S. S.; Jana, U. Tetrahedron 2003, 59, 813; (g) Ranu,
B. C.; Samanta, S. J. Org. Chem. 2003, 68, 7130; (h) Ranu,
B. C.; Das, A.; Hajra, A. Synthesis 2003, 1012; (i) Ranu, B.
C.; Samanta, S. Tetrahedron 2003, 59, 7901; (j) Ranu, B.
C.; Jana, R.; Samanta, S. Adv. Synth. Catal. 2004, 346,
446; (k) Ranu, B. C.; Das, A. Adv. Synth. Catal. 2005, 347,
712.
9. (a) Ranu, B. C.; Mandal, T.; Samanta, S. Org. Lett. 2003,
5, 1439; (b) Ranu, B. C.; Mandal, T. J. Org. Chem. 2004,
69, 5793; (c) Ranu, B. C.; Mandal, T. Synlett 2004, 1239;
(d) Ranu, B. C.; Das, A. Tetrahedron Lett. 2004, 45, 6875.
10. (a) Dulcere, J. P.; Mihoubi, M. N.; Rodriguez, J. J. Org.
Chem. 1993, 58, 5709; (b) Okabe, M.; Abe, M.; Tada, M.
J. Org. Chem. 1982, 47, 1775.
11. Representative experimental procedure for the synthesis of
2-(4-methoxyphenyl)-4-methylene-tetrahydrofuran-3-carb-
oxylic acid ethyl ester (entry 2). 2-Bromo-3-(4-methoxy-
phenyl)-(3-prop-2-ynyloxy)propionic acid ethyl ester
(341 mg, 1 mmol) in dry acetonitrile (8 mL) was sonicated
in an ultrasonic bath (bath temperature: 40–45 ꢁC) in the
presence of indium(I) iodide (242 mg, 1 mmol) for 3.5 h
(TLC). The reaction mixture was quenched with a few
drops of H2O. Acetonitrile was evaporated and the residue
was then extracted with ether (3 · 20 mL). The organic
extract was washed with brine, dried (Na2SO4), and
evaporated to leave the crude product, which was purified
by column chromatography over silica gel (hexane/ether
4:1) to give pure 2-(4-methoxyphenyl)-4-methylene-tetra-
(CDCl3, 300 MHz): d 22.4 (s, 3H), 3.65–3.68 (m, 1H),
3.88 (s, 3H), 4.45–4.50 (m, 2H), 5.07–5.21 (m, 5H), 6.78–
6.90 (m, 3H), 7.26–7.44 (m, 5H);13C NMR (CDCl3,
75 MHz): d 29.1, 55.9, 65.1, 70.8, 71.4, 82.8, 107.0,
109.4, 113.7, 118.1, 127.1 (2C), 127.7, 128.4 (2C), 133.2,
136.9, 146.7, 147.8, 149.7, 205.3. Anal. Calcd for
C21H22O4: C, 74.54; H, 6.55. Found: C, 74.36; H, 6.47.
2-(4-Allyloxy-3-methoxy-phenyl)-4-methylene-tetrahydro-
furan-3-carboxylic acid ethyl ester (entry 10). Colorless
1
liquid; IR (neat): 1512, 1596, 1632, 1732 cmÀ1; H NMR
(CDCl3, 300 MHz): d 1.28 (t, J = 7.20 Hz, 3H), 3.46–3.50
(m, 1H), 3.88 (s, 3H), 4.17–4.27 (m, 2H), 4.47–4.66 (m,
4H), 5.10–5.20 (m, 3H), 5.29–5.42 (m, 2H), 5.99–6.17 (m,
1H), 6.82–7.08 (m, 3H); 13C NMR (CDCl3, 75 MHz): d
14.1, 55.7, 56.9, 61.0, 69.7, 71.3, 83.2, 106.1, 109.3, 113.0,
117.8, 118.2, 122.2, 132.5, 133.1, 144.3, 146.4, 170.6. Anal.
Calcd for C18H22O5: C, 67.91; H, 6.97. Found: C, 67.82;
H, 6.86.
2-(3-Methoxy-4-prop-2-ynyloxy-phenyl)-4-methylene-tetra-
hydrofuran-3-carboxylic acid ethyl ester (entry 11). Col-
1
orless liquid; IR (neat): 1512, 1589, 1728, 2070 cmÀ1; H
NMR (CDCl3, 300 MHz): d 1.28 (t, J = 7.2 Hz, 3H), 2.51
(t, J = 2.4 Hz, 1H), 3.46–3.50 (m, 1H), 3.87 (s, 3H), 4.18–
4.29 (m, 2H), 4.46–4.66 (m, 2H), 4.75 (d, J = 2.4 Hz, 2H),
5.09–5.20 (m, 3H), 6.89–7.03 (m, 3H); 13C NMR (CDCl3,
75 MHz): d 14.1, 55.7, 56.8, 56.9, 61.0, 71.3, 75.6, 78.4,
83.1, 106.2, 109.4, 114.0, 118.2, 133.7, 146.3 (2C), 149.6,
170.5. Anal. Calcd for C18H20O5: C, 68.34; H, 6.37.
Found: C, 68.16; H, 6.32.
12. (a) Srikrishna, A.; Krishnan, K. Tetrahedron Lett. 1988,
29, 4995; (b) Jana, S.; Guin, C.; Roy, S. C. Tetrahedron
Lett. 2005, 46, 1155.
13. Dulcere, J. P.; Rodriguez, J.; Santelli, M.; Zahra, J. P.
Tetrahedron Lett. 1987, 28, 2009.