A solution of 12 (490 mg, 0.82 mmol) in THF (2 mL) was added to a suspension of 60% NaH (60 mg,
1.50 mmol) in THF (4 mL) at 0˚C. After 30 min at 0˚C, a solution of 10 (226 mg, 0.74 mmol) in THF (2
mL) was added over 30 min. After being stirred at rt overnight, the reaction mixture was poured into an
ice-water and extracted with EtOAc. The combined extracts were washed with water and brine, dried
(MgSO4) and concentrated in vacuo. The crude product obtained by the same work-up as described in the
preparation of 11 was chromatographed on silica gel (60 g) with hexane-CHCl3 (1:1) to yield 13 (560 mg,
-1
89%) as a colorless amorphous powder. IR 1590, 1500 cm ; EIMS m/z (rel. int.) 776 (M+, 23), 774 (M+,
63), 772 (M+, 19), 604 (17), 432 (10); 1H NMR (200 MHz) δ 3.84 (3H, s), 5.08 (2H, s), 5.11 (2H, s),
6.68–7.53 (27H, m); HRMS (EI) calcd for C43H34O4Br2 772.0824, found: 772.0804.
Hydrogenation of 13.
A solution of 13 (195 mg, 0.25 mmol) in CH2Cl2 (6 mL) was hydrogenated
over PtO2 (80 mg) under atmospheric pressure at rt. The catalyst was filtered off, and the filtrate was
concentrated in vacuo. The residue was chromatographed on silica gel (20 g) with CHCl3-EtOAc (9:1) to
afford the reduced product, which was dissolved in DMF (2 mL). This solution was added to a solution
of 60% NaH (48 mg, 1.2 mmol) at 0˚C under argon. After being stirred at 0˚C for 30 min, chloromethyl
methyl ether (0.1 mL, 1.2 mmol) was added. The reaction mixture was stirred at rt for 14 h. The reaction
mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed
with brine, dried (MgSO4) and concentrated in vacuo. The residue was chromatographed on silica gel (6
g) with CHCl3-hexane (9:1) to afford 7 (125 mg, 74%) as a colorless oil. IR 1574, 1508 cm-1; EIMS m/z
1
(rel. int.) 688 (M+, 50), 686 (M+, 90), 684 (M+, 47), 485 (42), 425 (100), 211 (50); H NMR (200 MHz) δ
2.82 - 2.98 (8H, m), 3.43 (3H, s), 3.44 (3H, s), 3.74 (3H, s), 5.09 (2H, s), 5.14 (2H, s), 6.64 (1H, dd, J =
8.4, 2.9 Hz), 6.71 (1H, d, J = 2.9 Hz), 6.76 (1H, dd, J = 8.4, 2.9 Hz), 6.78 - 6.89 (4H, m), 6.94 (1H, dd, J
= 8.4, 2.0 Hz), 7.12 (1H, d, J = 1.8 Hz), 7.16 (1H, d, J = 1.1 Hz), 7.40 (1H, d, J = 8.4 Hz), 7.42 (1H, d, J =
8.8 Hz); 13C NMR (50 MHz) δ 35.1, 35.2, 38.4, 38.6, 55.3, 55.9, 56.1, 94.4, 95.5, 113.2, 114.8, 115.8,
116.1, 117.8, 118.3, 121.2, 124.5, 129.5, 133.2, 133.3, 135.4, 136.2, 141.7, 141.8, 146.1, 146.9, 156.2,
156.5, 158.8; HRMS (EI) calcd for C33H34O6Br2 684.0710, found: 684.0722.
Intramolecular Stille-Kelly reaction of 7. To a solution of 7 (50 mg, 0.073 mmol) in toluene (10 mL)
was added hexamethylditin (26 mg, 0.08 mmol) and tetrakis(triphenylphosphine)palladium (4.2 mg,
0.0037 mmol). The reaction mixture in a sealed tube was heated at 120˚C for 24 h. After being filtered
and concentrated in vacuo, the crude product was purified by prep. TLC (hexane-EtOAc, 2:1) to yield 18
(7 mg, 17%), a mixture of 15 and 16 (2.7 mg, 9%) and the recovery 7 (11.7 mg, 45%) as a colorless oil,
respectively. 18: IR 1606, 1504, 1224, 1153 cm-1; EIMS m/z (rel. int.) 526 (M+, 100), 449 (12), 225 (49);
1H NMR (400 MHz) δ 2.10 (1H, m), 2.87–2.91 (3H, m), 3.05–3.12 (4H, m), 3.45 (3H, s), 3.57 (3H, s),
3.89 (3H, s), 5.12 (2H, s), 5.27 (2H, s), 5.30 (1H, d, J = 1.8 Hz), 6.68–6.78 (5H, m), 6.84 (1H, d, J = 8.3
Hz), 6.95 (3H, m), 7.02 (1H, d, J = 8.3 Hz), 7.03 (1H, d, J = 8.3 Hz), 7.21 (1H, d, J = 2.4 Hz); HRMS (EI)
calcd for C33H34O6 526.2355, found: 526.2364.
15 and 16: EIMS m/z (rel. int.) 754 (M+, 20).