Self-Assembly of Photochromic Diarylethenes
0.903 mmol), Pd(PPh3)4 (34.8 mg, 0.030 mmol), and aqueous
Na2CO3 (20 w %, 10 mL) were added to the solution. The solution
was refluxed for 16 h. The reaction product was extracted with
ethyl acetate (× 2), and the organic layer was washed with brine
(× 3), dried over MgSO4, filtered, and evaporated. The crude
product was purified by silica gel column chromatography (ethyl
acetate) to yield 9 (230 mg, 0.42 mmol, 69.8%) as a yellow oil. 1H
NMR (CDCl3, TMS, 200 MHz) δ 2.40 (s, 3H, Me), 3.38 (s, 3H,
Me), 3.52-4.20 (m, 24H), 6.91 (d, J ) 9 Hz, 2H, Ar), 6.98 (s,
1H), 7.42 (d, J ) 9 Hz, 2H, Ar); FAB HRMS (m/z) [M]+ calcd for
C24H35BrO7S, 546.1287; found, 546.1284.
(S)-p-Iodo-(2-{2-[2-(2-{2-[2-(2-methoxy-ethoxy)-ethoxy]-
ethoxy}-ethoxy)-ethoxy]-ethoxy}-propoxy)-benzene (15). The
compound 14 (0.80 g, 1.58 mmol) and p-iodophenol (0.41 g, 1.74
mmol) was added to a solution of K2CO3 (2.14 g, 15.5 mmol) in
DMF (15 mL). The solution was stirred for 7 h at 70 °C. After
cooling, the mixture was poured into aqueous HCl (pH ) 2, 200
mL) and extracted with CH2Cl2 (× 2), and the organic layer was
washed with brine (× 3) and dried over MgSO4. The solvent was
evaporated in vacuo. The crude product was purified by silica gel
column chromatography (AcOEt) to yield 15 (0.96 g, 1.78 mmol,
quant.) as a pale red oil. 1H NMR (CDCl3, TMS, 200 MHz) δ 1.29
(d, J ) 6 Hz, 3H, Me), 3.38 (s, 3H, Me), 3.45-4.60 (m, 27H),
6.71 (d, J ) 9 Hz, 2H, Ar), 7.53 (d, J ) 9 Hz, 2H, Ar); FAB
HRMS (m/z) [M]+ calcd for C22H37IO8, 556.1533; found, 556.1532.
(S)-3-Bromo-5-[4-(2-{2-[2-(2-{2-[2-(2-methoxy-ethoxy)-ethoxy]-
ethoxy}-ethoxy)-ethoxy]-ethoxy}-1-methyl-ethoxy)-phenyl]-2-
methyl-thiophene (16). To a solution of compound 15 (900 mg,
1.67 mmol) in dry THF (30 mL) was slowly added n-butyllithium
hexane solution (1.6 M, 1.15 mL, 1.84 mmol) at -78 °C under an
argon atomosphere. The solution was stirred for 1 h at -78 °C.
After the addition of boric acid tri-n-butyl ester (0.672 mL, 2.51
mmol), the reaction mixture was further stirred for 1 h. The reaction
was quenched by the addition of water. 2,4-Dibromo-5-methyl-
thiophene (642 mg, 2.51 mmol), Pd(PPh3)4 (96.5 mg, 0.084 mmol),
and aqueous Na2CO3 (20 w %, 30 mL) were added to the solution.
The solution was refluxed for 12 h. The reaction product was
extracted with AcOEt (× 2), and the organic layer was washed
with brine (× 3), dried over MgSO4, filtered, and evaporated. The
crude product was purified by silica gel column chromatography
(AcOEt) to yield 16 (400 mg, 0.66 mmol, 39.5%) as a pale yellow
1,2-Bis[5-(4-{2-[2-(2-{2-[2-(2-methoxyethoxy)ethoxy]ethoxy}-
ethoxy)ethoxy]ethoxy}phenyl)2-methylthiophene-3-yl]perfluo-
rocyclopentene (1). To a solution of compound 9 (383 mg, 0.678
mmol) in dry THF (5 mL) was slowly added n-butyllithium (BuLi)
hexane solution (1.6 M, 0.461 mL, 0.737 mmol) at -78 °C under
an argon atomosphere. The solution was stirred for 1 h at -78 °C.
After the addition of perfluorocyclopentene (0.042 mL, 0.302
mmol), the reaction mixture was further stirred for 1 h at that
temperature. The reaction was stopped by the addition of water.
The reaction product was extracted with ethyl acetate (× 2), and
the organic layer was washed with brine (× 3), dried over MgSO4,
filtered, and evaporated. The crude product was purified by silica
gel column chromatography (ethyl acetate/acetone ) 1:1) to yield
1
1 (70 mg, 0.063 mmol, 20.9%) as a blue oil. H NMR (CDCl3,
TMS, 400 MHz) δ 1.94 (s, 6H, Me), 3.37 (s, 6H, Me), 3.52-3.76
(m, 40H), 3.84-3.90 (m, 4H), 4.12-4.18 (m, 4H), 6.93 (d, J ) 9
Hz, 4H, Ar), 7.16 (s, 2H), 7.45 (d, J ) 9 Hz, 4H, Ar). FAB MS
(m/z) [M]+ 1108.83. Anal. Calcd for C53H70F6O14S2: C, 57.39; H,
6.36. Found: C, 57.19; H, 6.34. UV-vis (H2O) λmax (ꢀ) 289
(28 000); (AcOEt) λmax (ꢀ) 296 (48 000); (hexane) λmax (ꢀ) 294
(45 000).
1
oil. H NMR (CDCl3, TMS, 200 MHz) δ 1.32 (d, J ) 6 Hz, 3H,
Me), 2.40 (s, 3H, Me), 3.38 (s, 3H, Me), 3.52-3.80 (m, 26H), 4.57
(q, J ) 6 Hz, 1H), 6.92 (d, J ) 9 Hz, 2H, Ar), 6.98 (s, 1H), 7.41
(d, J ) 9 Hz, 2H, Ar); FAB HRMS (m/z) [M]+ calcd for C27H41-
BrO8S, 604.1706; found, 604.1728.
(S)-1-{2-[2-(2-{2-[2-(2-Methoxy-ethoxy)-ethoxy]-ethoxy}-
ethoxy)-ethoxy]-ethoxy}-propan-2-ol (13). To a solution of (S)-
2-(tetrahydropyran-2-yloxy)-propan-1-ol 12 (3.02 g, 18.7 mmol)
and p-toluenesulfonic acid Hxg monomethyl ether (12.8 g, 21.1
mmol) in dry THF (100 mL) was added NaH (1.27 g, 52.9 mmol).
The solution was refluxed for 12 h. After cooling, the reaction was
quenched by the addition of water, and the solution was evaporated
to remove THF. The reaction product was extracted with CH2Cl2
(× 2), and the organic layer was washed with brine (× 3), dried
over MgSO4, and evaporated. The crude product was dissolved in
MeOH (50 mL), and then TsOH‚H2O (0.6 g, 3.18 mmol) was added
at 0 °C. The solution was stirred for 4 h at room temperature and
quenched by aqueous NaHCO3. The reaction product was extracted
with AcOEt (× 2), and the organic layer was washed with brine
(× 3), dried over MgSO4, and evaporated. The crude product was
purified by silica gel column chromatography (AcOEt/acetone )
(S,S)-1,2-Bis-[5-(4-{2-[2-(2-{2-[2-(2-{2-methoxy-ethoxy}-ethoxy)-
ethoxy]-ethoxy}-ethoxy)-ethoxy]-1-methyl-ethoxy}-phenyl)-2-
methyl-thiophene-3-yl]-perfluorocyclopentene ((S,S)-2a). To a
solution of compound 16 (200 mg, 0.330 mmol) in dry THF (2
mL) was slowly added n-butyllithium hexane solution (1.6 M, 0.227
mL, 0.363 mmol) at -78 °C under an argon atomosphere. The
solution was stirred for 1 h at -78 °C. After the addition of a
solution of perfluorocyclopentene (0.021 mL, 0.149 mmol) in dry
THF (1.2 mL), the reaction mixture was further stirred for 1 h at
that temperature. The reaction was quenched by the addition of
water. The reaction product was extracted with AcOEt (× 2), and
the organic layer was washed with brine (× 3), dried over MgSO4,
filtered, and evaporated. The crude product was purified by silica
gel column chromatography (AcOEt/acetone ) 1:1) and separative
RP-HPLC (CH3CN/MeOH/H2O ) 9:1:2) to yield (S,S)-2a (50 mg,
1
1:1) to yield 13 (2.0 g, 5.64 mmol, 30.2%) as a colorless oil. H
NMR (CDCl3, TMS, 200 MHz) δ 1.13 (d, J ) 6 Hz, 3H, Me),
3.38 (s, 3H, Me), 3.45-4.02 (m, 27H); FAB HRMS (m/z) [M +
H]+ calcd for C16H35O8+, 355.2332; found, 355.2333.
1
0.041 mmol, 19.5%) as a blue oil. H NMR (CDCl3, TMS, 200
MHz) δ 1.32 (d, J ) 6 Hz, 6H, Me), 1.93 (s, 6H, Me), 3.38 (s, 6H,
Me), 3.45-3.80 (m, 52H), 4.50-4.68 (m, 2H), 6.93 (d, J ) 9 Hz,
4H, Ar), 7.16 (s, 2H), 7.45 (d, J ) 8 Hz, 4H, Ar); FAB MS (m/z)
[M]+ 1224.74. Anal. Calcd for C59H82F6O16S2: C, 57.83; H, 6.74.
Found: C, 57.53; H, 6.70. UV-vis (H2O) λmax (ꢀ) 295 (35 000);
(AcOEt) λmax (ꢀ) 294 (50 000).
Corresponding Closed-Ring Isomer (S,S)-2b (Mixture of
(S,R,R,S)-2b and (S,S,S,S)-2b). 1H NMR (CDCl3, TMS, 200 MHz)
δ 1.33 (d, J ) 6 Hz, 6H, Me), 2.14 (s, 6H, Me), 3.38 (s, 6H, Me),
3.45-3.80 (m, 52H), 4.50-4.68 (m, 2H), 6.57 (s, 2H), 6.94 (d, J
) 9 Hz, 4H, Ar), 7.49 (d, J ) 9 Hz, 4H, Ar); UV-vis (H2O) (ꢀ)
583 (16 000); (AcOEt) (ꢀ) 594 (25 000).
B. Photochemical Measurements. Photoirradiation was carried
out using a 500-W super-high-pressure mercury lamp or a 500-W
xenon lamp. Mercury lines of 313 and 578 nm were isolated by
passing the light through a combination of band-pass filters or sharp-
cut filters and a monochromator. Closed-ring isomers were separated
by reversed-phase HPLC (CH3CN/MeOH/H2O ) 9:1:4, flow )
(S)-Toluene-4-sulfonic Acid 2-{2-[2-(2-{2-[2-(2-Methoxy-
ethoxy)-ethoxy]-ethoxy}-ethoxy)-ethoxy]-ethoxy}-1-methyl-eth-
yl Ester (14). Sodium hydroxide (218 mg, 5.44 mol) was dissolved
in water (0.4 mL). A solution of 13 (1.5 g, 4.23 mmol) in THF
(0.4 mL) was added at 0 °C. Then a solution of p-TsCl (887 mg,
4.65 mmol) in THF (1.0 mL) was slowly dropped into the solution.
After warming to room temperature, the mixture was stirred for 7
h. Water (40 mL) was added to the reaction mixture and acidified
by 6 M H2SO4. The reaction product was extracted with CH2Cl2
(× 2), and the organic layer was washed with brine (× 3), dried
over MgSO4, and evaporated. The crude product was purified by
silica gel column chromatography (AcOEt/acetone ) 1:1) to yield
14 (1.6 g, 3.15 mmol, 74.5%) as a colorless oil. 1H NMR (CDCl3,
TMS, 200 MHz) δ 1.13 (d, J ) 6 Hz, 3H, Me), 2.45 (s, 3H, Ts),
3.38 (s, 3H, Me), 3.45-4.02 (m, 27H), 7.35 (d, J ) 8 Hz, 2H, Ar),
7.80 (d, J ) 8 Hz, 2H, Ar); FAB HRMS (m/z) [M + H]+ calcd for
C23H41O10S+, 209.2420; found, 509.2417.
J. Org. Chem, Vol. 71, No. 20, 2006 7507