4790 J . Org. Chem., Vol. 61, No. 14, 1996
Takahashi et al.
a suspension of PdCl2(PPh3)2 (12 mg, 0.017 mmol) in dry THF
(3 mL), and the mixture was stirred for 10 min at room
temperature. To the suspension of Pd(0)-catalyst were added
dropwise a solution of 9a (150 mg, 0.341 mmol) in dry THF (6
mL) and the THF solution of the above-prepared THF solution
of 10a . The reaction mixture was stirred for 1 h at room
temperature, poured into water, acidified with 1 N HCl, and
extracted with ether. The ether extract was washed (water,
then brine) and dried (Na2SO4). After evaporation under
reduced pressure, the residue was chromatographed on silica
gel (hexane:CH2Cl2 ) 95:5) to give 11a as pale yellow crystals
(160 mg, 0.222 mmol, 65.2%): mp 262-267 °C; IR (KBr) 3000-
2800 (m), 1466 (w), 1452 (w), 1416 (s), 1394 (w), 1362 (w), 1258
(s), 1220 (s), 1120 (m), 912 (s), 880 (m), 840 (s), 792 (m), 780
(m), 768 (m) cm-1; 1H NMR (400 MHz, CDCl3) δ 0.44 (s, 18H,
SiMe),1.45 (s, 36H, t-Bu), 7.11 (d, 2H, J ) 4.0 Hz, ThiH-3′,4′′),
7.13 (d, 2H, J ) 4.0 Hz, ThiH-4′,3′′), 7.50 (s, 4H, ArH-
2,2′′′,6,6′′′); 13C NMR (50.3 MHz, CDCl3) δ 3.94 (SiMe), 31.16
(CMe), 35.21 (CMe), 122.50 (ThiC-3′,4′′), 123.38 (ArC-2,2′′′,6,6′′′),
123.93 (ThiC-4′,3′′), 126.25 (ArC-1,1′′′), 135.84 (ThiC-5′,2′′),
141.31 (ArC-3,3′′′,5,5′′′), 143.86 (ThiC-2′,5′′), 153.87 (ArC-4,4′′′);
MS (FD) m/ z (rel intensity) 721 (M+ + 3, 10), 720 (M+ + 2,
39), 719 (M+ + 1, 60), 718 (M+, 100), 647 (6), 646 (16).
under reduced pressure. Water was added, and the mixture
was extracted with ether. The ether extract was washed
(water, then brine), dried (Na2SO4), and evaporated. The
residue was chromatographed on silica gel (hexane:ether )
95:5) to give 12a as pale orange needles (26 mg, 0.0452 mmol,
54.2%).
5,5′-Bis(3,5-d i-ter t-b u t yl-4-h yd r oxyp h en yl)-2,2′-b ifu -
r a n (12c). A 1.0 M THF solution of TBAF (166 mL, 0.166
mmol) was added to a solution of 11c (51.9 mg, 0.0755 mmol)
in dry THF (8 mL) at 0 °C, and the resulting solution was
stirred for 30 s at room temperature. After addition of water,
the reaction mixture was extracted with CH2Cl2. The CH2Cl2
extract was washed twice (brine), dried (Na2SO4), and evapo-
rated under reduced pressure, and the residue was chromato-
graphed on silica gel (hexane:CH2Cl2 ) 1:6) to afford 12c as
colorless crystals (39.5 mg, 0.0728 mmol, 96.3%): mp 229-
230 °C; IR (KBr) 3622 (m), 2958-2875 (m), 1425 (s), 1365 (w),
1311 (w), 1236 (s), 1151 (m), 1093 (w), 1018 (m), 885 (m), 775
(m), 702 (w) cm-1; 1H NMR (600 MHz, CDCl3) δ 1.50 (s, 36H,
t-Bu), 5.30 (s, 2H, OH), 6.58 (d, 2H, J ) 3.4 Hz, FurH-3′,4′′),
6.65 (d, 2H, J ) 3.4 Hz, FurH-4′,3′′), 7.56 (s, 4H, ArH-
2,2′′′,6,6′′′); 13C NMR (150 MHz, CDCl3) δ 30.25 (CMe), 34.40
(CMe), 104.85 (FurC-3′,4′′), 106.75 (FurC-4′,3′′), 120.96 (ArC-
2,2′′′,6,6′′′), 122.36 (ArC-1,1′′′), 136.26 (ArC-3,3′′′,5,5′′′), 145.36
(FurC-5′,2′′), 153.64 (ArC-4,4′′′), 154.12 (FurC-2′,5′′); MS (DEI)
m/ z (rel intensity) 544 (M+ + 2, 15), 543 (M+ + 1, 39), 542
(M+, 100); HRMS calcd for C36H46O4 542.3396, found 542.3398.
5,5′-Bis(3,5-d i-ter t-bu tyl-4-oxo-2,5-cycloh exa d ien -1-yli-
d en e)-5,5′-d ih yd r o-2,2′-bith iop h en e (3). (a) Under nitrogen
atmosphere, PbO2 (148 mg, 0.0619 mmol) was added to a
solution of 12a (35.6 mg, 0.0619 mmol) in dry benzene (30 mL),
and the reaction mixture was stirred vigorously at room
temperature for 30 min. After removal of the surplus PbO2
by filtration through Celite, the filtrate was evaporated under
reduced pressure, and the residue was chromatographed on
silica gel (CH2Cl2) to give 3 as shining deep green crystals (34.9
mg, 0.0609 mmol, 98.6%): mp 268 °C; IR (KBr) 2950-2860
(w), 1632 (w), 1566 (s), 1444 (m), 1360 (m), 1326 (m), 1258
(w), 1140 (w), 1110 (m), 1022 (m), 872 (m), 796 (m), 704 (m)
cm-1; UV/vis/NIR (CH3CN) λmax nm (log ꢀ) 725 sh (4.05), 678
5,5′-Bis(3,5-d i-ter t-b u t yl-4-(silyloxy)p h en yl)-2,2′-b ifu -
r a n (11c). Under nitrogen atmosphere, a pentane solution
of t-BuLi (1.57 M, 202 mL, 0.316 mmol) was added dropwise
into a solution of 8c (109.0 mg, 0.316 mmol) in dry ether (3
mL) at -40 °C, and the resulting solution was stirred for 60
min at the same temperature. To this was added dropwise a
cooled (0 °C) THF solution of anhydrous ZnCl2 (43 mg, 0.316
mmol), and the resulting solution was stirred for 60 min at
-40 °C to give organozinc chloride 10c in solution. On the
other hand, a Pd(0)-catalyst was prepared by treating Cl2Pd-
(PPh3)2 (7.4 mg, 0.0105 mmol) in dry THF (5 mL) with DIBAH
in hexane (1.5 M, 14 µL, 0.021 mmol). To this were added
sequentially under argon atmosphere a solution of 9c (88.9
mg, 0.211 mmol) in dry THF (5 mL) and the above-prepared
THF solution of 10c. The reaction mixture was warmed to
room temperature and stirred for 1 h at room temperature.
After a usual workup the crude reaction product was chro-
matographed on silica gel (hexane) to give 11c as colorless
crystals (121.4 mg, 0.177 mmol, 83.7%): mp 183-184 °C; IR
(KBr) 2958-2879 (w), 1473 (w), 1410 (s), 1362 (w), 1250 (s),
1
(4.50), 620 (4.15), 428 (3.62), 263 (3.63); H NMR (400 MHz,
CDCl3, -40 °C) for 3A δ 7.23 (d, 2H, J ) 2.4 Hz, ArH-6,6′′′),
7.41 (d, 2H, J ) 2.4 Hz, ArH-2,2′′′), 7.52 (d, 2H, J ) 5.5 Hz,
ThiH-3′,4′′), 7.55 (d, 2H, J ) 5.5 Hz, ThiH-4′,3′′); for 3B δ 7.23
(d, 2H, J ) 2.4 Hz, ArH-6,6′′′), 7.37 (d, 2H, J ) 5.5 Hz, ThiH-
3′,4′′), 7.41 (d, 2H, J ) 2.4 Hz, ArH-2,2′′′), 7.65 (d, 2H, J ) 4.8
Hz, ThiH-4′,3′′); δ 1.33, 1.35 (each s, 36H, t-Bu of 3A, 3B); MS
(FD) m/ z (rel intensity) 572 (M+, 100). (b) To a solution of
12a (24 mg, 0.0417 mmol) in CH2Cl2 (20 mL) were added a
0.1 M aqueous KOH solution (40 mL) and then potassium
ferricyanide (137 mg, 0.416 mmol) at room temperature, and
the mixture was stirred vigorously for 3 h. The reaction
mixture was extracted with CH2Cl2, and the extract was
washed (water, then brine), dried (Na2SO4), and evaporated
under reduced pressure. The residue was chromatographed
on silica gel (hexane:CH2Cl2 ) 1:1) to afford 3 as deep green
crystals (20 mg, 0.0349 mmol, 83.7%).
1203 (w), 1122 (w), 1018 (w), 930 (m), 849 (s), 773 (m) cm-1
;
1H NMR (600 MHz, CDCl3) δ 0.43 (s, 18H, SiMe), 1.47 (s, 36H,
t-Bu), 6.60 (d, 2H, J ) 3.3 Hz, FurH-3′,4′′), 6.66 (d, 2H, J )
3.3 Hz, FurH-4′,3′′), 7.63 (s, 4H, ArH-2,2′′′,6,6′′′); 13C NMR (150
MHz, CDCl3) δ 3.87 (SiMe), 31.20 (CMe), 35.22 (CMe), 105.17
(FurC-3′,4′′), 106.79 (FurC-4′,3′′), 121.61 (ArC-2,2′′′,6,6′′′),
122.91 (ArC-1,1′′′), 141.25 (ArC-3,3′′′,5,5′′′), 145.45 (FurC-5′,2′′),
153.03 (ArC-4,4′′′), 153.93 (FurC-2′,5′′); MS (DEI) m/ z (rel
intensity) 688 (M+ + 2, 25), 687 (M+ + 1, 59), 686 (M+, 100),
621 (13), 620 (26), 488 (10), 487 (24); HRMS calcd for C42H62O4-
Si2 686.4187, found 686.4191.
5,5′-Bis(3,5-d i-ter t-bu tyl-4-h yd r oxyp h en yl)-2,2′-bith io-
p h en e (12a ). (a) To a solution of 11a (142.3 mg, 0.198 mmol)
in dry THF (20 mL) was added a 1.0 M THF solution of TBAF
(435 µL, 0.435 mmol) at 0 °C, and the reaction mixture was
stirred for 30 s. Water was added, and the mixture was
extracted with CH2Cl2. After usual workup, the crude reaction
product was chromatographed on silica gel (hexane:CH2Cl2 )
2:1) to give 12a as orange crystals (112.7 mg, 0.196 mmol,
99.1%): mp 279-282 °C; IR (KBr) 3600 (m), 3000-2800 (m),
1420 (s), 1300 (w), 1234 (m), 1224 (m), 1140 (m), 1118 (w),
5,5′-Bis(3,5-d i-ter t-bu tyl-4-oxo-2,5-cycloh exa d ien -1-yli-
d en e)-5,5′-d ih yd r o-2,2′-bifu r a n (5). (a) In a manner similar
to (a) for 3, a solution of 12c (38.4 mg, 0.708 mmol) in dry
benzene (30 mL) was treated with PbO2 (169 mg, 0.708 mmol)
to give 5 as a deep green solid (37.7 mg, 0.069 mmol, 98.0%):
mp 247-248 °C; IR (KBr) 2954-2873 (w), 1582 (s), 1525 (s),
1454 (w), 1419 (w), 1360 (m), 1255 (w), 1196 (m), 1173 (s), 1119
(m), 1093 (w), 914 (s) cm-1; UV/vis/NIR (CH3CN) λmax nm (log
ꢀ) 730 sh (4.69), 662 (5.01), 601 sh (4.63), 402 (4.57), 381 (4.47),
1
876 (w), 786 (m), 698 (w) cm-1; H NMR (400 MHz, CDCl3) δ
1.50 (s, 36H, t-Bu), 5.30 (s, 2H, OH), 7.09 (d, 2H, J ) 3.8 Hz,
ThiH-3′,4′′), 7.13 (d, 2H, J ) 3.8 Hz, ThiH-4′,3′′), 7.42 (s, 4H,
ArH-2,2′′′,6,6′′′); 13C NMR (50.3 MHz, CDCl3) δ 30.25 (CMe),
34.42 (CMe), 122.41 (ThiC-3′,4′′), 122.83 (ArC-2,2′′′,6,6′′′),
123.94 (ThiC-4′,3′′), 125.73 (ArC-1,1′′′), 135.74 (ThiC-5′,2′′),
136.44 (ArC-3,3′′′,5,5′′′), 144.18 (ThiC-2′,5′′), 153.79 (ArC-4,4′′′);
MS (EI) m/ z (rel intensity) 576 (M+ + 2, 18), 575 (M+ + 1,
41), 574 (M+, 100), 57 (18).
1
357 (4.46), 334 (4.44), 280 (4.30); H NMR (400 MHz, CDCl3,
-40 °C) for 5A δ 7.26 (d, 2H, J ) 2.4 Hz, ArH-6,6′′′), 7.38 (d,
2H, J ) 4.8 Hz, FurH-3′,4′′), 7.52 (d, 2H, J ) 4.8 Hz, FurH-
4′,3′′), 7.61 (d, 2H, J ) 2.4 Hz, ArH-2,2′′′); for 5B δ 7.24 (d,
2H, J ) 2.4 Hz, ArH-6,6′′′), 7.28 (d, 2H, J ) 5.2 Hz, FurH-
3′,4′′), 7.32 (d, 2H, J ) 5.2 Hz, FurH-4′,3′′), 7.78 (d, 2H, J )
2.4 Hz, ArH-2,2′′′); δ 1.34, 1.36, 1.37 (72H, t-Bu, of 5A, 5B);
MS (DEI) m/ z (rel intensity) 542 (M+ + 2, 100), 541 (M+ + 1,
53), 540 (M+, 93), 483 (12); HRMS calcd for C36H44O4 540.3239,
found 542.3246. (b) In a manner similar to (b) for 3, a solution
(b) To a solution of 11a (60 mg, 0.0834 mmol) in THF (11
mL) was added 12 N HCl (1 mL). After being stirred for 17 h
at room temperature, the reaction mixture was evaporated