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M. L. Bell et al. / Tetrahedron 57 12001) 3507±3520
5.5.7. Dehydrobenzo[20]annulene 4. The required
butadiyne synthon was prepared from iodoarene 13
7969 mg, 2.0 mmol) and trimethylsilylbutadiyne 7294 mg,
2.4 mmol) using acetylene coupling procedure A. Chroma-
tography on silica gel 7hexanes) yielded the correct
The above iodoarene 7584 mg, 1.0 mmol) was reacted with
synthon 12 7454 mg, 1.2 mmol) using in situ desilylation/
alkynylation reaction procedure B. Chromatography on
silica gel 73:1 hexanes/CH2Cl2) yielded the bis-protected
polyyne 7580 mg, 76% yield) as a darkorange gum. 1H
NMR d 7.69±7.65 7m, 1H), 7.64±7.60 7m, 1H), 7.57±
7.46 7m, 6H), 7.32±7.23 7m, 8H), 1.13 7s, 21H), 1.10 7s,
21H); 13C NMR d 132.86, 132.71, 132.48, 132.30, 131.90,
128.72, 128.60, 128.05, 127.97, 127.89, 127.17, 126.93,
125.89, 125.77, 125.73, 125.69, 124.85, 124.35, 105.34,
104.55, 96.08, 95.09, 93.05, 92.42, 91.89, 91.74, 81.31,
81.04, 78.11, 77.90, 18.69, 11.33, 11.30.
1
product 7814 mg, 85% yield) as a yellow oil. H NMR
d 7.67±7.64 7m, 1H), 7.55±7.49 7m, 3H), 7.35±7.24
7m, 4H), 1.14 7s, 21H), 0.24 7s, 9H); 13C NMR d
132.84 72), 132.68, 131.79, 128.73, 128.09, 127.94,
127.92, 127.34, 125.68 72), 124.26, 105.24, 95.15,
93.09, 91.76, 91.24, 87.98, 78.07, 75.41, 18.72, 11.34,
20.37.
Iodoarene 13 7242 mg, 0.50 mmol) was reacted with
the above synthon 7287 mg, 0.60 mmol) using in situ
desilylation/alkynylation reaction procedure B. Chromato-
graphy on silica gel 73:1 hexanes/CH2Cl2) yielded the bis-
protected polyyne 7293 mg, 77% yield) as an orange gum.
1H NMR d 7.65±7.61 7m, 2H), 7.60±7.55 7m, 4H), 7.50±
7.46 7m, 2H), 7.38±7.28 7m, 4H), 7.24±7.19 7m, 4H), 1.18
7s, 42H); 13C NMR d 132.87, 132.72, 132.56, 131.80,
128.65, 128.12, 127.98, 127.94, 127.13, 125.50, 125.45,
124.69, 105.39, 94.93, 93.28, 91.28, 81.38, 77.99, 18.73,
11.35.
a,v-Polyyne 7100 mg, 0.131 mmol) was subjected to
macrocyclization reaction procedure C. Chromatography
on silica gel 73:1 hexanes/CH2Cl2) yielded DBA 9 736 mg,
1
61% yield) as a tan solid. H NMR d 7.64±7.59 7m, 2H),
7.57±7.52 7m, 4H), 7.51±7.46 7m, 2H), 7.40±7.28 7m, 8H);
13C NMR d 133.53, 133.39, 132.84, 132.06, 129.62, 129.58,
128.98, 128.87, 127.38, 126.97, 125.27, 124.47, 92.00,
90.78, 81.75, 80.88, 78.99, 77.45; IR 7KCl) n 3064,
2217 cm21; MS 7EI, 70 eV) m/z 448 7M1, 85); UV
7CH2Cl2): lmax 7e) 232 7239,000), 249 sh 7205,000), 280
sh 770,500), 314 755,000), 355 sh 715,000) nm; Anal.
Calcd for C36H16: C, 96.40; H, 3.60. Found: C, 96.17; H,
3.63.
a,v-Polyyne 7100 mg, 0.131 mmol) was subjected to
macrocyclization reaction procedure C. Chromatography
on silica gel 73:1 hexanes/CH2Cl2) yielded DBA 4 732 mg,
55% yield) as a yellow±orange solid. 1H NMR d 7.56±7.54
7m, 4H), 7.54±7.52 7m, 4H), 7.37±7.24 7m, 8H); 13C NMR
d 133.91, 131.64, 128.68, 128.21, 126.42, 125.02, 91.58,
80.99, 78.10; IR 7KCl) n 3053, 2213, 2173 cm21; MS
770 eV) m/z 448 7M1, 100); UV 7CH2Cl2): lmax 7e) 235 sh
732,300), 258 757,400), 271 759,300), 326 sh 717,900) nm;
Anal. Calcd for C36H16: C, 96.40; H, 3.60. Found: C, 96.25;
H, 3.55.
5.5.9. Dehydrobenzo[22]annulene 10. Bis72-iodophenyl)-
ethyne26 7323 mg, 0.75 mmol) was reacted with triyne 12
7663 mg, 1.75 mmol) using in situ desilylation/alkynylation
reaction procedure B. Chromatography on silica gel 74:1
hexanes/CH2Cl2) yielded the bis-protected polyyne
7354 mg, 60% yield) as a darkorange gum. 1H NMR d
7.67±7.64 7m, 2H), 7.55±7.47 7m, 6H), 7.37±7.22 7m,
8H), 1.14 7s, 42H); 13C NMR d 132.82, 132.75, 132.63,
132.31, 128.81, 128.60, 128.16, 127.92, 127.21, 126.69,
124.90, 124.47, 104.54, 96.12, 92.32, 81.37, 81.02, 78.15,
77.98, 18.67, 11.30.
5.5.8. Dehydrobenzo[20]annulene 9. The requisite iodo-
arene coupling partner was prepared as follows: compound
13 71.55 g, 3.2 mmol) was reacted with N,N-diethyl-N0-72-
ethynylphenyl)triazene19 7705 mg, 3.5 mmol) using
acetylene coupling procedure A. Chromatography on silica
gel 73:1 hexanes/CH2Cl2) yielded cross-coupled product
a,v-Polyyne 7100 mg, 0.127 mmol) was subjected to
macrocyclization reaction procedure C. Chromatography
on silica gel 73:1 hexanes/CH2Cl2) yielded DBA 10
1
735 mg, 59% yield) as a cream-colored solid. H NMR d
1
71.21 g, 69% yield) as a viscous orange oil. H NMR d
7.62±7.56 7m, 4H), 7.55±7.49 7m, 4H), 7.44±7.32 7m, 8H);
13C NMR d 134.09, 133.35, 132.80, 132.76, 129.73, 129.70,
129.62, 129.13, 126.60 72), 125.86, 124.72, 91.76, 81.55,
81.51, 80.60, 78.32, 78.25, 77.48; IR 7CH2Cl2) n 3062,
3022, 2215 cm21; MS 7EI, 70 eV) m/z 472 7100, M1);
UV 7CH2Cl2) lmax 7e) 240 7123,000), 270 7103,000),
295 725,000), 330 728,200), 350 sh 710,300) nm; Anal.
Calcd for C38H16: C, 96.59; H, 3.41. Found: C, 96.28; H,
3.46.
7.56±7.49 7m, 4H), 7.41 7d, J8.1 Hz, 1H), 7.30±7.17
7m, 6H), 7.03 7t, J7.5 Hz, 1H), 3.74 7q, J6.9 Hz, 4H),
1.26 7t, J6.9 Hz, 6H), 1.12 7s, 21H); 13C NMR d 152.35,
133.10, 132.63, 131.79, 131.56, 128.97, 127.92, 127.86,
127.74, 127.25, 126.86, 125.99, 125.59, 125.46, 124.56,
118.13, 116.93, 105.36, 94.91, 92.58, 92.32, 92.24, 92.08,
49.40, 41.94, 18.69, 11.31.
The resultant triaryltriazene 71.11 g, 2.0 mmol) in iodo-
methane 710 mL) was subjected to triazene decomposition
procedure D. Chromatography on silica gel 75:1 hexanes/
CH2Cl2) yielded the iodoarene coupling partner 71.07 g,
92% yield) as a pale orange oil. 1H NMR d 7.85 7d,
J8.1 Hz, 1H), 7.66±7.51 7m, 4H), 7.34±7.26 7m, 6H),
7.00 7t, J7.7 Hz, 1H), 1.09 7s, 21H); 13C NMR d 138.71,
132.92, 132.74, 132.40, 132.14, 129.93, 129.40, 128.12,
128.06, 128.00, 127.99, 127.72, 125.99, 125.89, 125.73,
125.51, 105.30, 100.73, 95.30, 92.42, 91.94, 91.92, 18.73,
11.35.
5.5.10. Dehydrobenzo[24]annulene 11. Bis72-iodophenyl)-
butadiyne14 7301 mg, 0.70 mmol) was reacted with triyne 12
7606 mg, 1.6 mmol) using in situ desilylation/alkynylation
reaction procedure B. Chromatography on silica gel 74:1
hexanes/CH2Cl2) yielded the bis-protected polyyne
1
7386 mg, 68% yield) as an orange gum. H NMR d 7.60±
7.45 7m, 8H), 7.36±7.20 7m, 8H), 1.17 7s, 42H); 13C NMR d
133.43, 133.31, 132.79, 132.23, 128.84, 128.69 72), 127.92,
127.17, 125.41, 125.07, 124.73, 104.54, 96.16, 81.83, 80.97,
80.30, 78.48, 78.26, 77.79, 18.70, 11.33.