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Helvetica Chimica Acta – Vol. 95 (2012)
7.35 – 7.40 (m, 2 arom. H); 7.23 (dd, J ¼ 4.8, 1.2, HꢀC(5) of Tph); 7.00 (dd, J ¼ 8.4, 2.0, 2 arom. H); 6.88
(dd, J ¼ 4.8, 3.4, HꢀC(4) of Tph); 6.85 (dd, J ¼ 3.4, 1.2, HꢀC(3) of Tph); 3.65 (dt, J ¼ 14.8, 2.0, HaꢀC(3));
3.38 (dt, J ¼ 14.8, 2.0, HbꢀC(3)); 2.49 – 2.52 (m, 2 H), 2.30 – 2.35 (m, 2 H), 2.03 – 2.10 (m, 2 H). 13C-NMR:
195.4 (C¼O); 175.2 (C(7a)); 163.7; 161.3; 148.6; 140.3; 127.5; 127.4; 127.0; 126.6; 125.9; 115.6; 115.4; 112.8
(C(3a)); 92.7 (C(2)); 42.4; 36.7; 24.2; 21.9. LC/ESI-MS: 315 (100, [M þ H]þ). Anal. calc. for C18H15FO2S:
C 68.8, H 4.8, F 6.0, S 10.2; found: C 68.9, H 4.9, F 6.1, S 10.1.
1-[3a,4,5,6,7,7a-Hexahydro-2-methyl-7a-(2-thienyl)benzofuran-3-yl]ethanone (6a): Yield 159.8 mg
(61%). Light yellow oil. IR: 2936, 2862 (aliph. CꢀH), 1616 (C¼O). 1H-NMR: 7.13 (dd, J ¼ 4.8, 1.2,
HꢀC(5) of Tph); 6.95 (dd, J ¼ 4.6, 3.6, HꢀC(4) of Tph); 6.89 (dd, J ¼ 3.6, 1.2, HꢀC(3) of Tph); 3.33 (t, J ¼
6.4, HꢀC(3a)); 2.22 (s, MeCOꢀC(3)); 2.19 (s, MeꢀC(2)); 2.00 – 2.07 (m, 2 H); 1.88 – 1.96 (m, 2 H); 1.51 –
1.60 (m, 2 H); 1.36 – 1.46 (m, 2 H). LC/ESI-MS: 263 (100, [M þ H]þ). Anal. calc. for C15H18O2S: C 68.7, H
6.9, S 12.2; found: C 68.6, H 6.8, S 12.3.
3,4,5a,6,7,8,9,9a-Octahydro-3,3-dimethyl-5a-(2-thienyl)dibenzofuran-1(2H)-one (6b): Yield 211.4 mg
(70%). Yellow oil. IR: 2934 (aliph. CꢀH), 1637 (C¼O). 1H-NMR: 7.24 (dd, J ¼ 5.2, 1.2, HꢀC(5) of Tph);
7.04 (dd, J ¼ 3.6, 1.2, HꢀC(3) of Tph); 6.97 (dd, J ¼ 5.0, 3.2, HꢀC(4) of Tph); 3.52 (t, J ¼ 6.0, HꢀC(9a));
2.32 (d, J ¼ 1.6, 2 H); 2.23 (s, 2 H); 2.11 – 2.20 (m, 2 H); 1.88 – 1.93 (m, 2 H); 1.55 – 1.58 (m, 2 H); 1.45 –
1.49 (m, 2 H); 1.13 (s, MeꢀC(3)); 1.10 (s, MeꢀC(3)). 13C-NMR: 195.2 (C¼O); 175.3 (C(4a)); 149.5; 127.0;
124.9; 123.5; 115.4 (C(9b)); 92.4 (C(5a)); 51.5; 45.7; 38.3; 34.4; 34.0; 29.2; 28.6; 24.1; 18.7; 18.6. LC/ESI-
MS: 303 (100, [M þ H]þ). Anal. calc. for C18H22O2S: C 71.2, H 7.3, S 10.6; found: C 71.3, H 7.2, S 10.7.
3,4,5a,6,7,8,9,9a-Octahydro-5a-(2-thienyl)dibenzofuran-1(2H)-one (6c): Yield 200.0 mg (73%). Yel-
low oil. IR: 3098, 3074 (arom. CꢀH), 2940, 2864 (aliph. CꢀH), 1635 (C¼O). 1H-NMR: 7.40 (dd, J ¼ 5.2,
1.2, HꢀC(5) of Tph); 7.04 (dd, J ¼ 3.8, 1.2, HꢀC(3) of Tph); 6.97 (dd, J ¼ 5.0, 3.8, HꢀC(4) of Tph); 3.51 (tt,
J ¼ 6.0, 1.2, HꢀC(9a)); 2.45 – 2.52 (m, 2 H); 2.31 – 2.37 (m, 2 H); 2.11 – 2.15 (m, 2 H); 2.02 – 2.07 (m, 2 H);
1.85 – 1.98 (m, 2 H); 1.50 – 1.65 (m, 2 H); 1.40 – 1.48 (m, 2 H). LC/ESI-MS: 274 (100, [M þ H]þ). Anal.
calc. for: C16H18O2S: C 70.0, H 6.6, S 11.7; found: C 70.1, H 6.5, S 11.8.
1-[3a,5,6,6a-Tetrahydro-2-methyl-6a-(2-thienyl)-4H-cyclopenta[b]furan-3-yl]ethanone (7a): Yield
198.4 mg (80%). Light yellow oil. IR: 2953 (aliph. CꢀH), 1666 (C¼O), 1598 (C¼C). 1H-NMR: 7.23
(dd, J ¼ 4.8, 1.6, HꢀC(5) of Tph); 6.95 – 6.99 (m, 2 H of Tph); 3.67 (d, J ¼ 8.8, HꢀC(3a)); 2.40 (dd, J ¼
13.4, 8.6, HꢀC(4)); 2.79 (d, J ¼ 1.6, MeꢀC(2)); 2.22 (s, MeCOꢀC(3)); 2.01 – 2.17 (m, 2 H); 1.80 – 1.85 (m,
2 H); 1.67 – 1.71 (m, 1 H). LC/ESI-MS: 249 (100, [M þ H]þ). Anal. calc. for C14H16O2S: C 67.7, H 6.5, S
12.9; found: C 67.6, H 6.4, S 13.0.
Ethyl 3a,5,6,6a-Tetrahydro-2-methyl-6a-(2-thienyl)-4H-cyclopenta[b]furan-3-carboxylate (7b): Yield
239.1 mg (86%). Yellow oil. IR: 2961, 2870 (aliph. CꢀH), 1695 (C¼O), 1644 (C¼C). 1H-NMR: 7.21 (dd,
J ¼ 5.0, 1.6, HꢀC(5) of Tph); 6.98 (dd, J ¼ 5.0, 3.6, HꢀC(4) of Tph); 6.94 (dd, J ¼ 3.4, 1.6, HꢀC(3) of
Tph); 4.10 – 4.21 (m, MeCH2O); 3.63 (d, J ¼ 8.0, HꢀC(3a)); 2,40 (dd, J ¼ 13.6, 7.8, HꢀC(4)); 2.25 (d, J ¼
1.4, MeꢀC(2)); 2.05 – 2.15 (m, 1 H); 1.85 – 2.00 (m, 2 H); 1.75 – 1.81 (m, 1 H); 1.63 – 1.73 (m, 1 H); 1.30 (t,
J ¼ 6.8, MeCH2O). 13C-NMR: 167.5 (C¼O); 166.2 (C(2)); 148.4; 122.8; 124.7; 127.1; 105.5 (C(3)); 97.0
(C(6a)); 59.6; 55.5; 43.0; 34.2; 24.6; 14.7; 14.4. LC/ESI-MS: 279 (100, [M þ H]þ). Anal. calc. for
C15H18O3S: C 64.7, H 6.5, S 11.5; found: C 64.6, H 6.6, S 11.6.
1,2,3,3a,5,6,7,8b-Octahydro-3a-(2-thienyl)-8H-cyclopenta[b]benzofuran-8-one (7c): Yield 243.9 mg
(89%). Yellow oil. IR: 3101 (arom. CꢀH), 2938, 2868 (aliph. CꢀH), 1631 (C¼O). 1H-NMR: 7.26 (dd, J ¼
4.0, 1.2, HꢀC(5) of Tph); 6.96 – 7.01 (m, 2 H of Tph); 3.71 (t, J ¼ 3.2, HꢀC(8b)); 2.44 – 2.49 (m, 2 H);
2.34 – 2.40 (m, 2 H); 2.00 – 2.14 (m, 2 H); 1.92 – 1.96 (m, 2 H); 1.81 – 1.86 (m, 2 H); 1.61 – 1.69 (m, 2 H).
LC/ESI-MS: 261 (100, [M þ H]þ). Anal. calc. for C16H18O2S: C 70.0, H 6.6, S 11.7; found: C 69.9, H 6.5, S
11.8.
[4,5-Dihydro-2-methyl-5-phenyl-5-(2-thienyl)furan-3-yl]phenylmethanone (8a): Yield 103.8 mg
(30%). Yellow oil. IR: 3065 (arom. CꢀH), 2926 (aliph. CꢀH), 1610 (C¼O). 1H-NMR: 7.55 (m, 2
arom. H); 7.24 – 7.47 (m, Ph, HꢀC(5) of Tph); 6.91 (dd, J ¼ 5.2, 3.6, HꢀC(4) of Tph); 6.88 (dd, J ¼ 3.6, 1.2,
HꢀC(3) of Tph); 3.90 (dq, J ¼ 14.8, 1.6, HaꢀC(4)); 3.72 (dq, J ¼ 14.8, 1.6, HbꢀC(4)); 1.93 (t, J ¼ 1.6,
MeꢀC(2)). 13C-NMR: 193.0 (C¼O); 171.3 (C(2)); 149.3; 144.6; 140.9; 131.4; 128.6; 128.5; 128.1; 126.8;
126.0; 125.8; 125.5; 112.6 (C(3)); 89.7 (C(5)); 47.1; 15.8. LC/ESI-MS: 347 (100, [M þ H]þ). Anal. calc. for
C22H18O2S: C 76.3, H 5.2, S 9.3; found: C 76.2, H 5.3, S 9.2.