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combined organic layers over magnesium sulfate, the solvent was removed
in vacuo. The product was used without further purification.
General Procedure for Sonogashira Coupling Reaction
To a flame-dried vessel were added the alkyne, the iodo compound (1.0 equiv
based on per alkyne), bis(dibenzylideneacetone)palladium(0) (5 mol % per
alkyne), triphenylphosphine(25 mol % per alkyne), copper(I) iodide (10 mol
% per alkyne), and THF/Et3N (2:1) at room temperature under argon. The
vessel was sealed and allowed to stir at room temperature for 2 days. The
reaction mixture was then subjected to an aqueous workup and the aqueous
layer was extracted three times with dichloromethane. After drying the
combined organic layers over magnesium sulfate, the solvent was removed
in vacuo to afford a crude product, which was then purified by column
chromatography (neutral alumina, 200–300 mesh).
Spectral data for oligomers:
Oligomer 4. 1H NMR (CDCl3, 600 MHz): d7.45 (d, J ¼ 8.4 Hz, 2H), 7.39
(d, J ¼ 8.4 Hz, 2H), 6.98 (s, 1H), 3.77 (q, J ¼ 7.2 Hz, 4H), 2.65 (t, J ¼ 7.8 Hz,
2H), 1.60 (p, J ¼ 7.2 Hz, 2H), 1.35 (sext, J ¼ 7.2 Hz, 2H), 1.27 (br s, 6H), 0.94
(t, J ¼ 7.2 Hz, 3H), 0.26 (s, 9H); 13C NMR (CDCl3, 150 MHz): d151.27,
148.64, 132.34, 132.18, 123.44, 120.44, 120.25, 118.69, 101.82, 97.05,
94.33, 82.39, 32.16, 32.05, 29.05, 22.18, 13.91, 13.81; LDI-MS: 436 (Mþ),
407 (M - C2H5), 363 (M - TMS), 336 (M – Et2N3).
Oligomer 7. 1H NMR (CDCl3, 600 MHz): d7.48 (d, J ¼ 8.4 Hz, 2H), 7.46
(s, 4H), 7.40 (d, J ¼ 8.4 Hz, 2H), 7.03 (s, 1H), 7.01 (s, 1H), 3.77
(q, J ¼ 7.2 Hz, 4H), 2.72 (t, J ¼ 7.2 Hz, 2H), 2.65 (t, J ¼ 7.2 Hz, 2H), 1.65–
1.59 (m, 4H), 1.41–1.34 (m, 4H), 1.26 (br s, 6H), 0.97–0.93 (m, 6H), 0.26
(s, 9H); 13C NMR (CDCl3, 150 MHz): d151.24, 148.63, 148.00, 132.91,
132.48, 132.12, 131.28, 131.11, 124.02, 123.07, 122.56, 122.41, 120.41,
120.18, 119.10, 118.59, 102.25, 96.80, 95.71, 94.89, 93.30, 84.70, 84.44,
82.38, 32.19, 32.07, 31.99, 29.16, 29.04, 28.98, 22.20, 22.13, 14.10, 13.87,
13.78; LDI-MS: 698 (Mþ), 669 (M–C2H5), 598 (M–Et2N3).
1
Oligomer 10. H NMR (CDCl3, 600 MHz): d7.49–7.47 (m, 14H), 7.40
(d, J ¼ 8.4 Hz, 2H), 7.09 (s, 2H), 7.05 (s, 1H), 7.02 (s, 1H), 3.78
(q, J ¼ 7.2 Hz, 4H), 2.75–2.72 (m, 6H), 2.66 (t, J ¼ 7.2 Hz, 2H), 1.69–1.57
(m, 8H), 1.41–1.32 (m, 8H), 1.27–1.20 (m, 6H), 0.98–0.94 (m, 12H), 0.26
(s, 9H); 13C NMR (CDCl3, 150 MHz): d151.32, 148.70, 148.12, 133.23,
133.01, 132.56, 132.19, 131.37, 131.23, 124.09, 123.20, 123.17, 123.04,
122.98, 122.65, 122.61, 122.56, 122.46, 120.45, 120.30, 120.05, 120.01,
119.16, 118.67, 102.35, 96.80, 96.10, 95.73, 94.90, 93.84, 93.78,
93.24, 84.81, 84.71, 84.51, 84.28, 84.21, 82.39, 32.24, 32.04, 29.21,
29.04, 22.25, 22.18, 13.90, 13.80; LDI-MS: MALDI-MS: 1223 (Mþ), 1123
(M–Et2N3).