*3-(Phenylethynyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)-o-xylene (21)*

The general procedure B was applied to 3-bromo-o-xylene (136 μL, 185 mg, 1.0 mmol, 1 equiv). The borylation step was carried out with HBpin (290 μL, 256 mg, 2.00 mmol, 2.00 equiv) for 10 h. The Sonogashira coupling step was carried out with phenyl acetylene (143 μL, 132 mg, 1.30 mmol, 1.3 equiv) for 18 h. Column chromatography (pentane/dichloromethane 1:2, R*<sup>f</sup>* 0.8) furnished the desired product as a yellow solid (255 mg, 77% yield, mp 104–105 ◦C).

1H NMR (CDCl3, 500 MHz): δ 7.90 (m, 1 H), 7.59 (m, 1 H), 7.57–7.53 (m, 2 H), 7.40–7.30 (m, 3 H), 2.52 (s, 3 H), 2.33 (s, 3 H), 1.38 (br s, 12 H, 4 CH3 of Bpin); 13C NMR {1H} (CDCl3, 125 MHz): δ 141.8 (C), 136.6 (CH), 136.2 (C), 136.0 (CH), 131.5 (2 CH), 128.4 (2 CH), 128.1 (CH), 123.9 (C), 123.0 (C), 92.9 (C), 89.1 (C), 83.9 (2 C), 25.0 (4 CH3 of Bpin), 20.2 (CH3), 17.9 (CH3); 11B NMR (CDCl3, 96 MHz): δ 30.7; FT-IR (neat) Іmax: 2978, 1398, 1389, 1143, 966, 854, 756, 686 cm<sup>−</sup>1; GC-MS (EI) *m*/*z* (% relative intensity): M<sup>+</sup> 332 (100), 318 (14), 275 (6), 247 (8), 232 (20), 218 (12); HRMS (FAB): *m*/*z* 332.1948 [(M+); Calcd for C22H25BO2: 332.19477].

#### *2-(Phenylethynyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)-m-xylene (22)*

The general procedure B was applied to 2-bromo-m-xylene (134 μL, 185 mg, 1.0 mmol, 1 equiv). The borylation step was carried out with HBpin (290 μL, 256 mg, 2.00 mmol, 2.00 equiv) for 4 h. The Sonogashira coupling step was carried out with phenyl acetylene (143 μL, 132 mg, 1.30 mmol, 1.3 equiv) for 40 h. Gradient column chromatography (hexanes/dichloromethane 2:1 → hexanes: dichloromethane 0:1) furnished the desired product as yellow oil (233 mg, 70% yield).

1H-NMR (CDCl3, 500 MHz): δ 7.57–7.53 (m, 2 H), 7.53 (m, 2 H), 7.39–7.32 (m, 3 H), 2.52 (t, *J* = 0.7 Hz, 6 H), 1.36 (br s, 12 H, 4 CH3 of Bpin); 13C-NMR {1H} (CDCl3, 125 MHz): δ 139.5 (2 C), 133.0 (2 CH), 131.6 (2 CH), 128.5 (CH), 128.4 (CH), 126.0 (C), 123.8 (C), 99.2 (C), 87.5 (C), 84.0 (2 C), 25.0 (4 CH3 of Bpin), 21.0 (2 CH3); 11B-NMR ((CD3)2CO, 96 MHz): δ 30.6; FT-IR (neat) Іmax: 2978, 1606, 1385, 1365, 1315, 1238, 1143, 856, 756, 686 cm<sup>−</sup>1; GC-MS (EI) *m*/*z* (% relative intensity): M<sup>+</sup> 332 (100), 318 (5), 247 (22), 233 (16), 218 (9); HRMS (FAB): *m*/*z* 332.1950 [(M<sup>+</sup>); Calcd for C22H25BO2: 332.1948].

#### *1,3-Bis-(trimethylsilylethynyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)-benzene (23)*

The general procedure B was applied to 1,3-di-bromobenzene (121 μL, 236 mg, 1.0 mmol, 1 equiv). The borylation step was carried out with HBpin (218 μL, 218 mg, 1.50 mmol, 1.50 equiv) for 8 h. The Sonogashira coupling step was carried out with trimethylsilyl acetylene (312 μL, 216 mg, 2.20 mmol, 2.2 equiv) for 2 h. Column chromatography (pentane/dichloromethane 2:1, R*<sup>f</sup>* 0.8) furnished the desired product as yellow oil (212 mg, 54% yield).

1H-NMR (CDCl3, 500 MHz): δ 7.84 (d, *J* = 1.7 Hz, 2 H), 7.64 (t, *J* = 1.7 Hz, 1 H), 1.32 (br s, 12 H, 4 CH3 of Bpin), 0.22 (s, 18 H, 6 CH3 of 2 TMS); 13C-NMR {1H} (CDCl3, 125 MHz): δ 138.1 (2 CH), 137.6 (CH), 123.1 (2 C), 104.2 (C), 94.9 (C), 84.3 (2 C), 25.0 (4 CH3 of Bpin), 0.1 (6 CH3 of 2 TMS); 11B NMR (CDCl3, 160 MHz): δ 29.7 (trace unidentified organoboronate at δ 33.9); FT-IR (neat) Іmax: 2961, 2899, 2154, 1583, 1412, 1371, 1250, 976, 844, 760, 702 cm<sup>−</sup>1; GC-MS (EI) *m*/*z* (% relative intensity): M<sup>+</sup> 396 (14), 382 (100), 282 (7); HRMS (FAB): *m*/*z* 396.2116 [(M<sup>+</sup>); Calcd for C22H33BO2Si: 396.2112].

#### *1,2-Bis-(trimethylsilylethynyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)-benzene (24)*

The general procedure B was applied to 1,2-di-bromobenzene (121 μL, 236 mg, 1.0 mmol, 1 equiv). The borylation step was carried out with HBpin (218 μL, 192 mg, 1.50 mmol, 1.50 equiv) for 16 h. The Sonogashira coupling step was carried out with [DABCO] (449 mg, 4.0 mmol, 4 equiv) and trimethylsilyl acetylene (340 μL, 236 mg, 2.40 mmol, 2.4 equiv) for 12 h. Gradient column chromatography (hexanes/dichloromethane 1:1 → hexanes: dichloromethane 0:1) furnished the desired product as a light yellow solid (226 mg, 57% yield, mp 123–124 ◦C).

1H-NMR (CDCl3, 500 MHz): δ 7.91 (dd, *J* = 1.3, 0.6 Hz, 1 H), 7.64 (dd, *J* = 7.7, 1.3 Hz, 1 H), 7.45 (dd, *J* = 7.7, 0.6 Hz, 1 H), 1.33 (br s, 12 H, 4 CH3 of Bpin), 0.27 (s, 9 H, 3 CH3 of 2 TMS), 0.26 (s, 9 H, 3 CH3 of 2 TMS); 13C-NMR {1H} (CDCl3, 125 MHz): δ 138.9 (CH), 134.0 (CH), 131.6 (CH), 128.2 (C), 125.3 (C), 103.5 (C), 103.4 (C), 100.0 (C), 98.4 (C), 84.3 (2 C), 25.0 (4 CH3 of Bpin), 0.20 (3 CH3 of 2 TMS), 0.16 (3 CH3 of 2 TMS); 11B-NMR ((CD3)2CO, 96 MHz): δ 31.0; FT-IR (neat) Іmax: 2978, 2961, 2899, 2157, 1599, 1390, 1356, 1250, 964, 924, 844, 760, 684 cm<sup>−</sup>1; GC-MS (EI) *m*/*z* (% relative intensity): M<sup>+</sup> 396 (88), 381 (57), 339 (18), 282 (100); HRMS (FAB): *m*/*z* 396.2119 [(M<sup>+</sup>); Calcd for C22H33BO2Si: 396.2112].
