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Helvetica Chimica Acta Vol. 85 (2002)
7.60 (d, J 8.2, 1 H). 13C-NMR (CDCl3): 143.8; 136.2; 133.0; 132.9; 131.4; 129.5; 128.4; 127.1; 126.7; 126.4;
125.0; 117.8; 21.5. Anal. calc. for C15H15NO2S: C 65.91, H 5.53, N 5.12, S 11.73; found: C 66.05, H 5.51, N 5.08,
S 11.65.
N-(2-Ethenylphenyl)-4-methyl-N-[2-(trimethylsilyl)ethynyl]benzenesulfonamide (9). BuLi (1.8 ml of a 1.6m
soln. in hexane; 2.9 mmol) was added to a soln. of 8 (0.71 g, 2.6 mmol) in abs. toluene (30 ml) under Ar at 08.
The mixture was allowed to warm to r.t., and then iodonium salt 10 (1.19 g, 2.6 mmol) was added in small
portions. The mixture was stirred for 14 h and then filtered through a plug of silica gel and evaporated. The
residue was purified by CC (silica gel; hexane/AcOEt 9 :1) to give 0.40 g (38%) of 9. Pale solid. M.p. 106 1078
(AcOEt). IR (KBr): 2130, 1590, 1480. 1H-NMR (CDCl3): 0.15 (s, 9 H); 2.49 (s, 3 H); 5.28 (d, J 10.9, 1 H); 5.74
(d, J 17.6, 1 H); 6.90 (m, 2 H); 7.18 (t, J 7.7, 1 H); 7.32 7.38 (m, 3 H); 7.64 (d, J 7.7, 1 H); 7.69 (d, J 8.2,
2 H). 13C-NMR (CDCl3): 145.0; 136.5; 135.6; 133.3; 131.5; 129.4; 129.3; 128.4; 128.3; 128.0; 126.1; 116.2; 95.6;
72.2; 21.6; 0.1. Anal. calc. for C20H23NO2SSi: C 65.00, H 6.27, N 3.79, S 8.68, Si 7.60; found: C 65.24, H 6.40,
N 3.68, S 8.49, Si 7.51.
N-(2-Ethenylphenyl)-N-ethynyl-4-methylbenzenesulfonamide (11). A soln. of 9 (0.15 g, 0.4 mmol) in anh.
THF (3 ml) was treated with Bu4NF (0.8 ml of a 1.0m soln. in THF) at 08. The mixture was stirred at 08 for
45 min, and then it was diluted with hexane/AcOEt (20 ml), washed three times with H2O (20 ml), dried
(MgSO4), and evaporated. The residue was purified by CC (silica gel; hexane/AcOEt 9 :1) to give 0.08 g (70%)
of 11. White solid. M.p. 109 1108 (AcOEt). IR (KBr): 3280, 2120, 1590, 1480. 1H-NMR (CDCl3): 2.47 (s, 3 H);
2.81 (s, 1 H); 5.28 (d, J 11.0, 1 H); 5.75 (d, J 17.6, 1 H); 6.91 (m, 2 H); 7.19 (t, J 7.7, 1 H); 7.27 7.39
(m, 3 H); 7.65 (d, J 7.7, 1 H); 7.71 (d, J 8.2, 2 H). 13C-NMR (CDCl3): 145.3; 145.4; 136.9; 135.5; 133.8; 131.5;
129.9; 128.7; 128.5; 128.4; 126.5; 116.8; 77.2; 58.3; 21.9. Anal. calc. for C17H15NO2S: C 68.66, H 5.08, N 4.71,
S 10.78; found: C 68.80, H 5.20, N 4.63, S 10.57.
Pauson-Khand Reaction of 11. A soln. of [Co2(CO)8] (110 mg, 0.31 mmol) in toluene (10 ml) was added to
a soln. of 11 (78 mg, 0.26 mmol) in toluene (10 ml) in the presence of molecular sieves (625 mg) under Ar and at
r.t. The formation of the carbonylcobalt complex was monitored by TLC (SiO2; hexane/AcOEt 9 :1). After
complete formation of the complex, a suspension of trimethylamine N-oxide (179 mg, 2.34 mmol) in toluene
(10 ml) was added at À108, and the mixture was allowed to warm to r.t. overnight. The mixture was then filtered
through Celite and evaporated. The residue was chromatographed on silica gel (elution with hexane/AcOEt
9 :1) to give 12 mg of the desired 2,3-dihydro-4-[(4-methylphenyl)sulfonyl]-1H-cyclopenta[b]indol-2-one (12)
together with starting material. 1H-NMR (CDCl3): 2.42 (s, 3 H); 3.42 (s, 2 H); 3.79 (s, 2 H); 7.05 7.47 (m, 5 H);
7.95 (m, 1 H); 8.01 8.21 (m, 2 H).
2-[2-(Trimethylsilyl)ethynyl]aniline (14). To a soln. of 1.16 g (5.00 mmol) of 2-iodoaniline (13; in 15 ml of
dry Et3N, 0.85 ml (6.00 mmol) of ethynyl(trimethyl)silane, 70 mg (0.10 mmol) of [Pd(PPh3)2Cl2], and 4.8 mg
(0.02 mmol) of CuI were added. The reaction was kept at 608 for 5 h and was then cooled to r.t. The solvent was
evaporated, and the residue dissolved in toluene and filtered through Celite. The filtrate was concentrated and
purified by FC (hexane/Et2O 5%): 0.92 g (91%) of pure 14. Yellow oil. IR (NaCl): 3480, 3380, 2140. 1H-NMR
(CDCl3): 0.24 (s, 9 H); 4.20 (br. s, 2 H); 6.61 6.67 (m, 2 H); 7.09 (t, J 7.9, 1 H); 7.26 (d, J 7.7, 1 H ) . 13C-NMR
(CDCl3): 148.2; 132.2; 129.8; 117.6; 114.1; 107.7; 101.8; 99.6; 0.1. Anal. calc. for C11H15NSi: C 69.78, H 7.99,
N 7.40, Si 14.83; found: C 69.85, H 8.07, N 7.33, Si 14.76.
N-{2-[2-(Trimethylsilyl)ethynyl]phenyl}acetamide (15). A mixture of 1.57 g (8.31 mmol) of 14 in 50 ml of
Et2O and 2.44 ml (17.40 mmol) of Et3N was cooled to 08 and treated with 1.18 ml (16.50 mmol) of AcCl for 1 h to
obtain, after the usual workup, 1.7 g (88%) of pure 15. Colorless oil. IR (NaCl): 3320, 2140, 1670. 1H-NMR
(CDCl3): 0.31 (s, 9 H); 2.22 (s, 3 H); 7.02 (t, J 7.7, 1 H); 7.33 (t, J 8.2, 1 H); 7.41 (d, J 7.7, 1 H); 8.00 (br. s,
1 H); 8.39 (d, J 8.2, 1 H). 13C-NMR (CDCl3): 168.0; 139.4; 131.4; 129.9; 123.1; 118.8; 111.4; 102.2; 100.2; 24.8;
À0.1. Anal. calc. for C13H17NOSi: C 67.49, H 7.41, N 6.05, Si 12.14; found: C 67.77, H 7.60, N 6.01, Si 12.02.
N-(2-Ethynylphenyl)-N-(prop-2-enyl)acetamide (16). A soln. of 1.41 g (6.10 mmol) of 15 and 0.6 ml
(6.70 mmol) of allyl bromide in 15 ml of anh. THF was slowly added to a sonicated suspension of 750 mg
(13.40 mmol) of KOH and 900 mg (2.44 mmol) of Bu4Nl in 30 ml of dry THF. After 5 h sonication, the crude
mixture was filtered through Celite, and the solid washed with Et2O. The org. phase was washed with H2O and
brine. Evaporation of the solvent yielded 1.19 g (98%) of pure 16. Pale yellow oil. IR (NaCl): 3280, 2100, 1660.
1H-NMR (CDCl3): 1.86 (s, 3 H); 3.27 (s, 1 H); 3.99 (dd, J 14.8, 7.1, 1 H); 4.67 (dd, J 14.8, 6.1, 1 H); 5.01 5.09
(m, 2 H); 5.87 5.89 (m, 1 H); 7.71 (d, J 7.7, 1 H); 7.33 7.40 (m, 2 H); 7.59 (d, J 7.7, 1 H ) . 13C-NMR (CDCl3):
169.9; 144.2; 133.6; 132.9; 129.7; 129.0; 127.8; 121.8; 117.8; 82.5; 79.4; 51.0; 22.1. Anal. calc. for C13H13NO:
C 78.36, H 6.58, N 7.03; found: C 78.28, H 6.66, N 7.05.
5-Acetyl-3,3a,4,5-tetrahydro-2H-cyclopenta[c]quinolin-2-one (17). To a soln. of 200 mg (1.00 mmol) of 16
in 30 ml of anh. toluene, 1.60 g of molecular sieves, and 410 mg (1.20 mmol) of [Co2(CO)8] were added. After