Supporting Information Comparative studies on electronic spectra and redox behaviors of isomeric benzo[1,2-b:4,5-b']difurans and benzo[1,2-b:5,4-b']difurans Naoto Hayashi,a,* Yoko Saito,a Hiroyuki Higuchi,a and Kengo Suzukib a
Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama 9308555,
Japan, and bHamamatsu Photonics K. K., Jyoko, Hamamatsu, Shizuoka 431-3196, Japan
Corresponding author: Email
[email protected] Page
Contents Figure S1. Synthesis of 1a-2c
2
Synthesis
2
Figure S2. HOMO orbitals of 1a (a), 2a (b), 5 (c), 6 (d), 7 (e), 8 (f), 9 (g), and 10 (h)
7
calculated by HF/3-21G* methods Table S1. Molecular modeling coordinates of 1a, 1d-e, 2a, 2d-e, and 5-10
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8
(H3C)3Si I AcO
H
OAc
PdCl2(PPh3)2 CuI
I
i-Pr2NH
(H3C)3Si OAc
THF MS 4A
AcO
(H3C)3Si
AcO
1a
Si(CH3)3
3a
I
TBAF
H
I
PdCl2(PPh3)2 CuI
OAc
i-Pr2NH
(H3C)3Si
Si(CH3)3 TBAF OAc
AcO
2a
THF MS 4A
4a
R I AcO
H
OAc
PdCl2(PPh3)2 CuI
I
i-Pr2NH
R OAc
collidine
AcO
I AcO
1b-c
R
3b-c R
LiI
H
I
PdCl2(PPh3)2 CuI
OAc
i-Pr2NH
R
R LiI collidine AcO
2b-c
OAc 4b-c
b: R = n-C4H9 OC6H13 c: R = OC6H13
Figure S1. Synthesis of 1a-2c
Synthesis General. All commercially available chemicals were used without further purification except THF and 1,4-dioxane, which were distilled over sodium benzophenone ketyl and calcium hydride, respectively, before use. All reactions were performed in standard glassware under an inert argon atmosphere. 1
H and 13C NMR spectra were recorded on a JEOL JNM-ECP600 (600 MHz for 1H and 150 MHz 2/18
for 13C) or JEOL ECX-300/TRH (300 MHz for 1H and 75 MHz for
13
C) with tetramethylsilane as
internal reference. Mass spectra were conducted on a JEOL MStation JMS-700 (EI) and a JEOL JMS-SX102A (HRMS/EI). Elemental analyses were performed on a YANACO MT-5.
Synthesis
of
2,5-bis(trimethylsilylethynyl)-1,4-diacetoxybenzene
(3a)
and
4,6-bis(trimethylsilylethynyl)-1,3-diacetoxybenzene (4a) A solution of 2,5-diiodo-1,4-diacetoxybenzene (0.21 g, 0.47 mmol), CuI (3.6 mg, 0.019 mmol), trimethylsilylacetylene (0.14 mL, 1.3 mmol) in triethylamine (10 mL) and 1,4-dioxane (10 mL) was degassed with argon. After dichlorobis(triphenylphosphine)palladium (6.6 mg, 0.009 mmol) was added, the reaction mixture was stirred at 50 ºC for 4 h. After addition of water, organic layer was separated, and aqueous layer was extracted with ethyl acetate. Combined organic phase was washed with 3 N-HCl, brine, dried over MgSO4, and evaporated to dryness. From the crude product, 2,5-bis(trimethylsilylethynyl)-1,4-diacetoxybenzene (0.13 g, 72%) was isolated by preparative chromatography (SiO2, 1:9 ethyl acetate-hexane) as a colorless solid. Mp 164-166 ºC. 1H NMR (600 MHz, CDCl3): δ = 0.23 (18H, s, SiCH3), 2.30 (6H, s, CH3CO), 7.20 (2H, s, Ar).
13
C NMR
(150 MHz, CDCl3): δ = -7.27, 13.66, 23.89, 95.44, 111.57, 119.48, 142.15, 161.23. MS: m/z = 386 (M+). HRMS (m/z): 386.1369 (M+, calcd. 386.1370 for C20H26O4Si2). Compound 4a was also obtained from 4,6-diiodo-1,3-diacetoxybenzene in a similar manner. Yield 86%. Mp 69-71 ºC (lit.1 65-66 ºC). 1H NMR (600 MHz, CDCl3): δ = 0.23 (18H, s, SiCH3), 2.30 (6H, s, CH3CO), 6.92 (1H, s, Ar), 7.63 (1H, s, Ar). 13C NMR (150 MHz, CDCl3): δ = -0.24, 20.70, 98.07, 100.36, 115.36, 116.90, 137.18, 152.08, 167.83. MS: m/z = 386 (M+). HRMS (m/z): 386.1369 (M+, calcd. 386.1370 for C20H26O2Si2). Synthesis of benzo[1,2-b:4,5-b']difuran (1a) and benzo[1,2-b:5,4-b']difuran (2a) A mixture of tetra-n-butylammonium fluoride (1 mol/L in THF, 0.80ml, 0.80 mmol) in the presence of molecular sieves 4A (0.2 g) in THF (10 mL) was degassed with argon and the resulting solution was stirred at room temperature for 1 h. Then a solution of 3a (0.10 g, 0.26 mmol) in THF (5 mL) was added and the whole was stirred at 60 ºC for 4 h. The suspension was cooled to room temperature and filtered to remove any solid impurity. The filtrate was extracted with n-pentane. Combined organic phase was washed with brine, dried over MgSO4, and evaporated to dryness. From the crude product, benzo[1,2-b:4,5-b']difuran (0.036 g, 89%) was isolated by preparative chromatography (SiO2, n-pentane) as a colorless solid. Mp 104-106 ºC. 1H NMR (600 MHz,
1
Z. Liang, et. al., J. Org. Chem. 2007, 72, 9219-9224. 3/18
CDCl3): δ = 6.82 (2H, d, furan, J = 2.2 Hz), 7.63 (2H, d, Ar, J = 2.2 Hz), 7.64 (2H, s, Ar). 13C NMR (150 MHz, CDCl3): δ =102.08, 106.72, 125.48, 145.64, 152.04. Compound 2a was also obtained from 4a in a similar manner. Yield 52%. Mp 59-60 ºC (lit.2 62.5 ºC). 1H NMR (600 MHz, CDCl3): δ = 6.82 (2H, d, furan, J = 2.2 Hz), 7.63 (2H, d, furan, J = 2.2 Hz), 7.63 (1H, s, Ar), 7.71 (1H, s, Ar).
13
C NMR (150 MHz, CDCl3): δ = 94.46, 106.40, 111.34,
124.27, 145.27, 153.41.
Synthesis
of
2,5-di(1-hexyn-1-yl)-1,4-dimethoxybenzene
2,5-bis(3,5-dihexyloxyphenyl)-1,4-dimethoxybenzene
(3b), (3c),
4,6-di(1-hexyn-1-yl)-1,3-dimethoxybenzene
(4b),
and
4,6-bis(3,5-dihexyloxyphenyl)-1,3-dimethoxybenzene (4c) A solution of 2,5-diiodo-1,4-dimethoxybenzene (0.20 g, 0.51 mmol), CuI (4.9 mg, 0.026 mmol), 1-hexyne (0.13 mL, 1.1 mmol) in diisopropylamine (10 mL) was degassed with argon. After dichlorobis(triphenylphosphine)palladium (36.0 mg, 0.051 mmol) was added, the reaction mixture was stirred at ambient temperature for 2 h. After addition of water, organic layer was separated, and aqueous layer was extracted with ethyl acetate. Combined organic phase was washed with 3 mol L-1 HCl, brine, dried over MgSO4, and evaporated to dryness. From the crude product, 3b (0.14 g, 90%) was isolated by preparative chromatography (SiO2, 1:9 ethyl acetate-hexane) as a white solid. Mp 65-68 ºC. 1H NMR (300 MHz, CDCl3): δ = 0.95 (6H, t, CH3, J = 7.2 Hz), 1.43-1.67 (8H, m, CH2), 2.48 (4H, t, C≡CH2, J = 7.2 Hz), 3.83 (6H, s, OCH3), 6.86 (2H, s, Ar).
13
C NMR (75 MHz,
CDCl3): δ = 13.66, 19.54, 22.07, 30.85, 36.38, 95.99, 113.19, 115.79, 153.72. MS: m/Z = 298 (M+). Anal. Calcd. For C20H26O2: C, 80.50%; H, 8.78%. Found: C, 80.26%; H, 8.82%. Compound
3c
was
also
obtained
from
2,5-diiodo-1,4-dimethoxybenzene
and
(3,5-dihexyloxyphenyl)acetylene in a similar manner. Yield 49%. Mp 69-71 ºC. 1H NMR (600 MHz, CDCl3): δ = 0.91 (12H, t, CH3, J = 7.0 Hz), 1.32-1.36 (16H, m, CH2), 1.42-1.47 (8H, m, CH2), 1.74-1.79 (8H, m, CH2), 3.90 (6H, s, OCH3), 3.94 (8H, t, OCH2, J = 6.6 Hz), 6.46 (2H, t, Ar, J = 2.2 Hz), 6.70 (4H, d, Ar, J = 2.2 Hz), 7.02 (2H, s, Ar). 13C NMR (150 MHz, CDCl3): δ = 14.02, 22.59, 25.68, 29.16, 31.55, 56.47, 68.16, 84.95, 95.25, 102.97, 109.92, 113.32, 115.70, 121.62, 124.22, 153.90, 160.01. MS: m/Z = 739 ([M+1]+). HRMS (m/z): 738.4869 (M+, calcd. 738.4859 for C48H66O6). Compound 4b was also obtained from 4,6-diiodo-1,3-dimethoxybenzene and 1-hexyne. Yield 96%.
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Mp 46-48 ºC. 1H NMR (300 MHz, CDCl3): δ = 0.94 (6H, t, CH3, J = 7.2 Hz), 1.44-1.62 (8H, m, CH2), 2.44 (4H, t, C≡CH2, J = 7.2 Hz), 3.89 (6H, s, OCH3), 6.36 (1H, s, Ar) , 7.38 (1H, s, Ar). 13C NMR (75 MHz, CDCl3): δ = 13.65, 19.40, 21.99, 30.96, 55.98, 75.61, 93.20, 94.76, 105.40, 138.16, 160.51. MS: m/Z = 298 (M+). Anal. Calcd. For C20H26O2: C, 80.50%; H, 8.78%. Found: C, 80.34%; H, 8.79%. 4c
Compound
was
also
obtained
from
4,6-diiodo-1,3-dimethoxybenzene
and
(3,5-dihexyloxyphenyl)acetylene. Yield 94%. Mp 67-69 ºC. 1H NMR (600 MHz, CDCl3): δ = 0.91 (12H, t, CH3, J = 7.0 Hz), 1.32-1.35 (16H, m, CH2), 1.42-1.47 (8H, m, CH2), 1.74-1.79 (8H, m, CH2), 3.94 (8H, t, OCH2, J = 6.6 Hz), 3.96 (6H, s, OCH3), 6.43 (2H, t, Ar, J = 2.2 Hz), 6.44 (1H, s, Ar), 6.67 (4H, d, Ar, J = 2.2 Hz), 7.62 (1H, s, Ar). 13C NMR (150 MHz, CDCl3): δ = 14.02, 22.59, 25.68, 29.17, 31.55, 56.08, 68.15, 84.17, 92.63, 94.91, 102.57, 104.93, 109.77, 124.70, 138.12, 159.96, 161.46. MS: m/Z = 738 (M+). HRMS (m/z): 738.4863 (M+, calcd. 738.4859 for C48H66O6). Synthesis
of
2,6-dibutylbenzo[1,2-b:4,5-b']difuran
2,6-bis(3,5-dihexyloxyphenyl)benzo[1,2-b:4,5-b']difuran 2,6-dibutylbenzo[1,2-b:5,4-b']difuran
(1b), (1c),
(2b),
and
2,6-bis(3,5-dihexyloxyphenyl)benzo[1,2-b:5,4-b']difuran (2c) A solution of 3b (0.41 g, 1.37 mmol), LiI (1.83 g, 13.7 mmol) in collidine (10 mL) was refluxed for 36 h. After cooling and removing solvent, the reaction mixture was subjected to preparative chromatography (SiO2, 1:9 ethyl acetate-hexane) to isolate 1b (0.36 g, 98%) as a white solid. Mp 63-65 ºC (lit.3 55-56 ºC). 1H NMR (300 MHz, CDCl3): δ = 0.94 (6H, t, CH3, J = 7.2 Hz), 1.35-1.47 (4H, m, CH2), 1.67-1.77 (4H, m, CH2), 2.74 (4H, t, C≡CH2, J = 7.2 Hz), 6.36 (2H, s, furan) , 7.41 (2H, s, Ar).
13
C NMR (75 MHz, CDCl3): δ = 13.79, 22.29, 28.33, 29.72, 100.55, 101.88, 125.81,
151.60, 159.80. MS: m/Z = 270(M+). Anal. Calcd. For C18H22O2: C, 79.96%; H, 8.20%. Found: 79.95%; H, 8.31%. Compound 1c was also obtained from 3c in a similar manner as a white powder. Yield 14%. Mp 55-57 ºC. 1H NMR (600 MHz, CDCl3): δ = 0.92 (12H, t, CH3, J = 7.0 Hz), 1.36-1.38 (16H, m, CH2), 1.47-1.52 (8H, m, CH2), 1.79-1.84 (8H, m, CH2), 4.03 (8H, t, OCH2, J = 6.6 Hz), 6.47 (2H, t, Ar, J = 2.2 Hz), 7.02 (4H, d, Ar, J = 2.2 Hz), 7.07 (2H, s, Ar), 7.61 (2H, s, Ar).
13
C NMR (150 MHz,
CDCl3): δ = 14.05, 22.61, 25.75, 29.25, 31.59, 68.21, 101.54, 101.89, 102.09, 103.41, 127.28, 132.09, 152.09, 156.49, 160.60. MS: m/Z = 711 ([M+1]+). HRMS (m/z): 710.4544 (M+, calcd. 710.4546 for C46H62O6). 3
Z. Liang, et. al., Tetrahedron 2007, 63, 12877-12882. 5/18
Compound 2b was also obtained from 4b as a white powder. Yield 34%. Mp 33-35 ºC (lit.3 38 ºC). 1
H NMR (300 MHz, CDCl3): δ = 0.95 (6H, t, CH3, J = 7.2 Hz), 1.36-1.48 (4H, m, CH2), 1.68-1.78
(4H, m, CH2), 2.75 (4H, t, C≡CH2, J = 7.2 Hz), 6.37 (2H, s, furan), 7.43 (1H, s, Ar), 7.44 (1H, s, Ar). 13
C NMR (75 MHz, CDCl3): δ = 13.81, 22.29, 28.27, 29.74, 93.51, 101.45, 109.14, 125.24, 152.36,
159.53. MS: m/Z = 270 (M+). Anal. Calcd. For C18H22O2: C, 79.96%; H, 8.20%. Found: 79.83%; H, 8.40%. Compound 2c was also obtained from 4c as a pale yellow solid. Yield 5%. Mp 46-48 ºC. 1H NMR (600 MHz, CDCl3): δ = 0.93 (12H, t, CH3, J = 7.0 Hz), 1.36-1.38 (16H, m, CH2), 1.47-1.52 (8H, m, CH2), 1.79-1.84 (8H, m, CH2), 4.03 (8H, t, OCH2, J = 6.6 Hz), 6.47 (2H, s, Ar), 7.01 (4H, d, Ar, J = 2.2 Hz), 7.04 (2H, s, Ar), 7.64 (1H, s, Ar), 7.64 (1H, s, Ar). 13C NMR (150 MHz, CDCl3): δ = 14.05, 22.61, 25.75, 29.26, 31.59, 68.21, 94.20, 101.50, 101.75, 103.33, 110.80, 126.12, 132.10, 153.37, 156.21, 160.61. MS: m/Z = 711 ([M+1]+). HRMS (m/z): 710.4547 (M+, calcd. 710.4546 for C46H62O6).
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Figure S2. HOMO orbitals of 1a (a), 2a (b), 5 (c), 6 (d), 7 (e), 8 (f), 9 (g), and 10 (h) calculated by HF/3-21G* methods
7/18
Table S1. Molecular modeling coordinates of 1a, 1d-e, 2a, 2d-e, and 5-10
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