*3.2. Synthesis of Ethynylpyrroles* **4a**–**k***, Ethynylindole* **6***, Ethynylfuran* **8***, General Procedure*

Acylethynylpyrrole **1a**–**k**, 3-acylethynylindole **5** or 2-acylethynylfuran **7** (1 mmol) was dissolved in dry THF/MeCN (1:1, 4 mL), and then *t*-BuOK (224 mg, 2 mmol) was added to reaction mixture under nitrogen. Reaction mixture was stirred at room temperature for 1 h while turning into an orange suspension. Then reaction mixture was diluted with cold (0–5 ◦C) water (30 mL) and extracted by cold (0–5 ◦C) *n*-hexane (3 × 10 mL). Combined extracts were washed with water (3 × 5 mL) and dried over Na2SO4. The residue, after removing solvent, was purified by flash chromatography (dried SiO2, *n*-hexane) to afford ethynylpyrrole **4a**–**k**, ethynylindole **6** and ethynylfuran **8**.

*1-Benzyl-2-ethynyl-4,5,6,7-tetrahydro-1H-indole* (**4a**). Yield: 197 mg (84%), colorless oil; 1H NMR (400.13 MHz, CDCl3): δ 7.37–7.24 (m, 3H, H*m,p,* Ph), 7.13–7.08 (m, 2H, H*o,* Ph), 6.37 (s, 1H, H-3, pyrrole), 5.14 (s, 2H, CH2-Ph), 3.35 (s, 1H, ≡CH), 2.54–2.49 (m, 2H, CH2-7), 2.43–2.38 (m, 2H, CH2-4), 1.82–1.68 (m, 4H, CH2-5, CH2-6); 13C NMR (100.6 MHz, CDCl3): δ 138.3, 130.9, 128.7 (2C), 127.3, 126.7 (2C), 118.0, 114.2, 99.7, 81.2, 77.0, 47.9, 23.5, 23.2, 23.1, 22.5; IR (KBr) 3287, 3087, 3063, 3030, 2928, 2849, 2097, 1495, 1457, 1388, 1357, 1301, 1130, 1077, 1029, 928, 795, 722, 696, 545, 457 cm<sup>−</sup>1; Anal. Calcd for C17H17N: C, 86.77; H, 7.28; N, 5.95%. Found: C, 86.47; H, 7.31; N, 6.14%.

*2-Ethynyl-1-methyl-4,5,6,7-tetrahydro-1H-indole* (**4b**). Yield: 137 mg (86%), white crystals, mp 53–54 ◦C; 1H NMR (400.13 MHz, CDCl3): δ 6.26 (s, 1H, H-3, pyrrole), 3.50 (s, 3H, NMe), 3.37 (s, 1H, ≡CH), 2.52–2.50 (m, 2H, CH2-7), 2.47–2.45 (m, 2H, CH2-4), 1.83–1.80 (m, 2H, CH2-5), 1.73–1.71 (m, 2H, CH2-6); 13C NMR (100.6 MHz, CDCl3,): δ 130.9, 117.4, 113.6, 112.6, 81.1, 76.9, 30.8, 23.6, 23.2, 23.0, 22.4; IR (film) 3288, 3100, 2929, 2847, 2097, 1570, 1462, 1442, 1386, 1302, 1130, 1055, 790, 667, 536 cm<sup>−</sup>1; Anal. Calcd for C11H13N: C, 82.97; H, 8.23; N, 8.80%. Found: C, 82.71; H, 8.44; N, 8.58%.

*2-Ethynyl-1-vinyl-4,5,6,7-tetrahydro-1H-indole* (**4c**). Yield: 127 mg (74%), colorless oil; 1H NMR (400.13 MHz, CDCl3): δ 6.97 (dd, *J* = 16.1, 9.4 Hz, 1H, Hx), 6.34 (s, 1H, H-3, pyrrole), 5.34 (d, *J* = 16.1 Hz, 1H, Ha), 4.83 (d, *J* = 9.4 Hz, 1H, Hb), 3.39 (s, 1H, ≡CH), 2.66–2.63 (m, 2H, CH2-7), 2.48–2.45 (m, 2H, CH2-4), 1.83–1.80 (m, 2H, CH2-5), 1.71–1.69 (m, 2H, CH2-6); 13C NMR (100.6 MHz, CDCl3): <sup>δ</sup> 130.5, 119.5, 116.8, 112.3, 102.1, 99.7, 82.1, 76.8, 24.2, 23.4, 23.1, 23.0; IR (film) 3292, 3128, 3049, 2932, 2849, 2099, 1643, 1577, 1483, 1438, 1387, 1324, 1294, 1136, 966, 871, 802, 669, 558 cm−1; Anal. Calcd for C12H13N: C, 84.17; H, 7.65; N, 8.18%. Found: C, 83.85; H, 7.81; N, 8.36%.

*5-Ethynyl-2,3-dimethyl-1-vinyl-1H-pyrrole* (**4d**). Yield: 52 mg (36%), colorless oil; 1H NMR (400.13 MHz, CDCl3): δ 6.91 (dd, *J* = 16.0, 9.2 Hz, 1H, Hx), 6.36 (s, 1H, H-3, pyrrole), 5.46 (d, *J* = 16.1 Hz, 1H, Ha), 4.94 (d, *J* = 9.2 Hz, 1H, Hb), 3.37 (s, 1H, ≡CH), 2.21 (s, 3H, Me), 1.99 (s, 3H, Me); 13C NMR (100.6 MHz, CDCl3): δ 130.8, 127.8, 119.0, 116.7, 111.6, 104.5, 81.7, 76.9, 11.4, 11.1; IR (film) 3291, 3106, 2920, 2866, 2099, 1643, 1483, 1432, 1392, 1335, 1310, 1162, 1113, 965, 879, 806, 671, 562 cm−1; Anal. Calcd for C10H11N: C, 82.72; H, 7.64; N, 9.65%. Found: C, 82.94; H, 7.49; N, 9.80%.

*2-Ethynyl-1-methyl-5-phenyl-1H-pyrrole* (**4e**). Yield: 172 mg (95%), colorless oil; 1H NMR (400.13 MHz, CDCl3): δ 7.42–7.34 (m, 5H, Ph), 6.55 (d, *J* = 3.8 Hz, 1H, H-3, pyrrole), 6.16 (d, *<sup>J</sup>* = 3.8 Hz, 1H, H-4, pyrrole), 3.69 (s, 3H, NMe), 3.44 (s, 1H, ≡CH); 13C NMR (100.6 MHz, CDCl3): δ 136.7, 132.9, 128.9 (2C), 128.6 (2C), 127.5, 116.1, 115.6, 108.6, 82.0, 76.5, 33.2; IR (film) 3287, 3106, 3060, 2948, 2102, 1602, 1498, 1457, 1390, 1324, 1234, 1155, 1074, 1028, 758, 698, 568 cm−1; Anal. Calcd for C13H11N: C, 86.15; H, 6.12; N, 7.73%. Found: C, 85.75; H, 5.86; N, 7.48%.

*2-Ethynyl-5-(4-methylphenyl)-1-vinyl-1H-pyrrole* (**4f**). Yield: 174 mg (84%), colorless oil; 1H NMR (400.13 MHz, CDCl3): δ 7.34–7.28 (m, 2H, H*o,* Ph), 7.24–7.17 (m, 2H, H*m,* Ph), 6.82 (dd, *J* = 15.9, 9.0 Hz, 1H, Hx), 6.63 (d, *J* = 3.8 Hz, 1H, H-3 pyrrole), 6.17 (d, *J* = 3.8 Hz, 1H, H-4, pyrrole), 5.53 (d, *J* = 15.9 Hz, 1H, Ha), 4.99 (d, *J* = 9.0 Hz, 1H, Hb), 3.43 (s, 1H, ≡CH), 2.38 (s, 3H, Me); 13C NMR (100.6 MHz, CDCl3): δ 137.6, 136.1, 131.1, 129.6, 129.2 (2C), 129.1 (2C), 118.5, 114.5, 109.9, 107.0, 82.5, 76.8, 21.3; IR (KBr) 3287, 3112, 3024, 2921, 2102, 1643, 1547, 1510, 1466, 1419, 1389, 1324, 1297, 1226, 1113, 963, 889, 822, 775, 672, 571, 500 cm−1; Anal. Calcd for C15H13N: C, 86.92; H, 6.32; N, 6.76%. Found: C, 86.68; H, 6.51; N, 6.85%.

*1-Benzyl-2-ethynyl-5-(4-methoxyphenyl)-1H-pyrrole* (**4g**). Yield: 253 mg (88%), white crystals; mp 92–93 ◦C; 1H NMR (400.13 MHz, CDCl3): δ 7.30–7.22 (m, 3H, H*m,p,* Ph), 7.20–7.15 (m, 2H, H*o,* Ph), 6.99–6.93 (m, 2H, H*m,* Ph), 6.87–6.82 (m, 2H, H*o,* Ph), 6.63 (d, *J* = 3.7 Hz, 1H, H-3 pyrrole), 6.16 (d, *J* = 3.7 Hz, 1H, H-4, pyrrole), 5.25 (s, 2H, CH2-Ph), 3.80 (s, 3H, MeO), 3.29 (s, 1H, ≡CH); 13C NMR (CDCl3, 100.6 MHz): <sup>δ</sup> 159.3, 138.8, 136.7, 130.4 (2C), 128.6 (2C), 127.2, 126.3 (2C), 125.3, 116.1, 115.5, 114.0 (2C), 108.8, 81.8, 76.6, 55.4, 48.9; IR (KBr) 3287, 3087, 3063, 3031, 2955, 2934, 2836, 2100, 1611, 1575, 1547, 1510, 1463, 1442, 1392, 1358, 1321, 1288, 1249, 1178, 1110, 1087, 1031, 977, 909, 836, 767, 731, 695, 575, 524, 459 cm<sup>−</sup>1; Anal. Calcd for C20H17NO: C, 83.59; H, 5.96; N, 4.87; O, 5.57%. Found: C, 83.31; H, 6.02; N, 5.02%.

*2-Ethynyl-5-(2-fluorophenyl)-1-vinyl-1H-pyrrole* (**4h**). Yield: 192 mg (91%), colorless oil; 1H NMR (400.13 MHz, CDCl3): δ 7.40–7.30 (m, 2H, H*m,* Ph), 7.22–7.08 (m, 2H, H*o,p,* Ph), 6.84 (dd, *J* = 15.9, 8.9 Hz, 1H, Hx), 6.66 (d, *J* = 3.7 Hz, 1H, H-3 pyrrole), 6.24 (d, *J* = 3.7 Hz, 1H, H-4, pyrrole), 5.34 (d, *<sup>J</sup>* = 15.9 Hz, 1H, Ha), 4.91 (d, *<sup>J</sup>* = 8.9 Hz, 1H, Hb), 3.45 (s, 1H, <sup>≡</sup>CH); 13C NMR (100.6 MHz, CDCl3): <sup>δ</sup> 159.9 (d, *<sup>J</sup>* = 249.1 Hz, C-2, 2-FC6H4), 132.1 (d, *<sup>J</sup>* = 2.0 Hz, C-6, 2-FC6H4), 130.9, 130.1 (d, *J* = 8.2 Hz, C-4, 2-FC6H4), 129.2, 124.24 (d, *J* = 3.3 Hz, C-5, 2-FC6H4), 120.6 (d, *J* = 15.5 Hz, C-1, 2-FC6H4), 118.1, 116.1 (d, *J* = 22.0 Hz, C-3, 2-FC6H4), 115.2, 111.8, 106.4, 82.7, 76.4; IR (KBr) 3293, 3115, 3068, 2924, 2104, 1645, 1580, 1547, 1498, 1465, 1397, 1300, 1229, 1109, 963, 890, 817, 780, 759, 672, 577, 471 cm−1; Anal. Calcd for C14H10FN: C, 79.60; H, 4.77; F, 8.99; N, 6.63%. Found: C, 79.24; H, 4.96; F, 8.75; N, 6.39%.

*5-Ethynyl-2,3-diphenyl-1-vinyl-1H-pyrrole* (**4i**). Yield: 242 mg (90%), white crystals; mp 93–94 ◦C; 1H NMR (400.13 MHz, CDCl3): δ 7.39–7.34 (m, 3H, H*o,p,* Ph), 7.31–7.26 (m, 2H, H*o,* Ph), 7.21–7.15 (m, 2H, H*m,* Ph), 7.15–7.09 (m, 3H, H*m,p,* Ph), 6.84 (s, 1H, H-3 pyrrole), 6.71 (dd, *J* = 15.9, 9.2 Hz, 1H, Hx), 5.47 (d, *J* = 15.9 Hz, 1H, Ha), 4.91 (d, *J* = 9.2 Hz, 1H, Hb), 3.46 (s, 1H, ≡CH); 13C NMR (100.6 MHz, CDCl3): <sup>δ</sup> 135.1, 131.9, 131.8, 131.4 (2C), 130.8, 128.7 (2C), 128.3 (2C), 128.2 (3C), 126.1, 123.8, 118.6, 113.7, 106.5, 82.8, 76.5; IR (KBr) 3274, 3080, 3057, 2923, 2100, 1641, 1601, 1557, 1495, 1446, 1386, 1320, 1305, 1177, 1031, 964, 889, 800, 769, 699, 587, 522 cm−1; Anal. Calcd for C20H15N: C, 89.19; H, 5.61; N, 5.20%. Found: C, 88.89; H, 5.45; N, 5.34%.

*2-Ethynyl-1-methyl-5-(thiophen-2-yl)-1H-pyrrole* (**4j**). Yield: 174 mg (93%), colorless oil; 1H NMR (400.13 MHz, CDCl3): δ 7.32–7.28 (m, 1H, H-5, thiophene), 7.10–7.05 (m, 2H, H-3,4, thiophene), 6.51 (d, *J* = 3.9 Hz, 1H, H-3 pyrrole), 6.26 (d, *J* = 3.9 Hz, 1H, H-4, pyrrole), 3.76 (s, 3H, N-CH3), 3.43 (s, 1H, ≡CH); 13C NMR (100.6 MHz, CDCl3): <sup>δ</sup> 134.4, 129.2, 127.5, 125.8, 125.3, 116.6, 115.6, 109.7, 99.7, 82.2, 33.2; IR (KBr) 3288, 3106, 3074, 2944, 2922, 2101, 1445, 1417, 1395, 1345, 1314, 1201, 1034, 845, 766, 698, 570, 493 cm<sup>−</sup>1; Anal. Calcd for C11H9NS: C, 70.55; H, 4.84; N, 7.48; S, 17.12%. Found: C, 70.26; H, 4.69; N, 7.28; S, 16.82%.

*1-Benzyl-2-ethynyl-1H-pyrrole* (**4k**). Yield: 145 mg (80%), colorless oil; 1H NMR (400.13 MHz, CDCl3): δ 7.36–7.27 (m, 3H, H*m,p,* Ph), 7.16–7.14 (m, 2H, H*o,* Ph), 6.68–6.65 (m, 1H, H-3, pyrrole), 6.54–6.51 (m, 1H, H-5, pyrrole), 6.13–6.10 (m, 1H, H-4, pyrrole), 5.19 (s, 2H, CH2-Ph), 3.33 (s, 1H, ≡CH); 13C NMR (CDCl3, 100.6 MHz): <sup>δ</sup> 137.9, 128.8 (2C), 127.7, 127.3 (2C), 123.1, 116.0, 114.7, 108.7, 81.7, 76.0, 51.3; IR (KBr) 3288, 3106, 3064, 3031, 2925, 2853, 2103, 1495, 1466, 1455, 1435, 1300, 1018, 722, 694, 569, 522 cm−1; Anal. Calcd for C13H11N: C, 86.15; H, 6.12; N, 7.73%. Found: C, 85.84; H, 5.89; N, 7.45%.

*3-Ethynyl-1-methyl-1H-indole* (**6**). Yield: 113 mg (73%); Spectral characteristics are the same as previously published [64].

*2-Ethynyl-3,6-dimethyl-4,5,6,7-tetrahydrobenzofuran* (**8**). Yield: 139 mg (80%), colorless oil; 1H NMR (400.13 MHz, CDCl3): δ 3.55 (s, 1H, ≡CH), 2.67–2.62 (m, 1H, CH), 2.33–2.30 (m, 2H, CH2), 2.19–2.12 (m, 1H, CH), 2.00 (s, 3H, Me), 1.93–1.91 (m, 1H, CH), 1.85–1.81 (m, 1H, CH), 1.36–1.30 (m, 1H, CH), 1.07 (d, *J* = 6.7 Hz, 3H, CHMe); 13C NMR (100.6 MHz, CDCl3): δ 152.1, 131.5, 127.2, 118.4, 83.8, 74.7, 31.7, 31.2, 29.6, 21.5, 20.0, 9.0; IR (KBr) 3293, 2923, 2849, 2103, 1628, 1558, 1456, 1379, 1295, 1257, 1150, 1107, 1066, 1041, 774, 692 cm−1; Anal. Calcd for C12H14O: C, 82.72; H, 8.10; O, 9.18%. Found: C, 82.94; H, 7.88%.
