8
Tetrahedron
°C) δ (ppm): 1.96 (t, J = 1.6 Hz, 3 H), 4.31-4.38 (m, 2 H), 4.44
for 24 h, to the reaction mixture was added water. The
heterogeneous mixture was extracted thrice with ethyl acetate,
and the combined organic layers were dried over Na2SO4 and
evaporated in vacuo. The residue was purified by silica gel
column chromatography (hexane/ethyl acetate = 5:1) to give
dithiocarbonate 4a (2nd fraction, main product) and
trithiocarbonate 5a (1st fraction, minor product).
(dd, J = 13.2, 3.2 Hz, 1 H), 4.59 (dd, J = 8.4, 8.4 Hz, 1 H), 4.95-
5.02 (m, 1 H), 5.67 (quin, J = 1.4 Hz, 1 H)), 6.14-6.19 (m, 1 H).
13C NMR (100 MHz, CDCl3, 25 °C) δ (ppm): 18.1, 63.4, 66.0,
73.8, 127.3, 135.1, 154.4, 166.6. IR (neat): ṽ = 2986, 2960, 2930,
1798, 1724, 1637, 1162, 1052 cm-1. MS (EI): m/z = 186 [M]+.
4-10-3. (n-Butoxymethyl)ethylene carbonate (3d): Colorless oil
(169 mg, 97%). H NMR (400 MHz, CDCl3, 25 °C) δ (ppm):
1
4-12-1.
5-(Phenoxymethyl)-1,3-oxathiolane-2-thione
(4a):
Colorless oil (199 mg, 88%). 1H NMR (400 MHz, CDCl3, 25 °C)
δ (ppm): 3.70 (dd, J = 11.2, 7.2 Hz, 1 H), 3.77 (dd, J = 11.2, 8.0
Hz, 1 H), 4.25 (dd, J = 10.2, 4.6 Hz, 1 H), 4.30 (dd, J = 10.4, 5.6
Hz, 1 H), 5.37-5.45 (m, 1H), 6.91 (dd, J = 8.8, 0.8 Hz, 2 H), 7.00
(t, J = 7.6 Hz, 1 H), 7.30 (dd, J = 8.8, 7.2 Hz, 2 H). 13C NMR
(100 MHz, CDCl3, 25 °C) δ (ppm): 36.1, 66.2, 87.8, 114.4, 121.7,
129.6, 157.6, 211.4. IR (neat): ṽ = 2926, 2870, 1597, 1495, 1185,
1045 cm-1. MS (EI): m/z = 226 [M]+.
0.92 (t, J = 7.4 Hz, 3 H), 1.36 (sext, J = 7.4 Hz, 2 H), 1.56 (quin,
J = 7.1 Hz, 2 H), 3.51 (t, J = 6.6 Hz, 2 H), 3.60 (dd, J = 11.0, 3.8
Hz, 1 H), 3.67 (dd, J = 10.8, 4.0 Hz, 1 H), 4.39 (dd, J = 8.0, 6.0
Hz, 1 H), 4.50 (t, J = 8.2 Hz, 1 H), 4.78-4.85 (m, 1 H). 13C NMR
(100 MHz, CDCl3, 25 °C) δ (ppm): 13.7, 19.1, 31.4, 66.2, 69.6,
71.8, 75.1, 155.0. IR (neat): ṽ = 2959, 2934, 2871, 1793, 1171,
1053 cm-1. MS (EI): m/z = 174 [M]+.
4-10-4. (Allyloxymethyl)ethylene carbonate (3e): Colorless oil
(157 mg, 99%). H NMR (400 MHz, CDCl3, 25 °C) δ (ppm):
1
4-12-2. 4-(Phenoxymethyl)-1,3-dithiolane-2-thione (5a): Yellow
solid (8.1 mg, 3.3%). H NMR (400 MHz, CDCl3, 25 °C) δ
1
3.63 (dd, J = 11.0, 3.8 Hz, 1 H), 3.70 (dd, J = 11.0, 4.2 Hz, 1 H),
4.01-4.12 (m, 2 H), 4.41 (dd, J = 8.2, 5.8 Hz, 1 H), 4.51 (dd, J =
8.2, 8.2 Hz, 1 H), 4.79-4.86 (m, 1 H), 5.24 (dd, J = 10.2, 1.4 Hz,
1 H), 5.29 (dq, J = 17.4, 1.4 Hz, 1 H), 5.82-5.93 (m, 1 H). 13C
NMR (100 MHz, CDCl3, 25 °C) δ (ppm): 66.3, 68.8, 72.6, 74.9,
118.0, 133.6, 154.9. IR (neat): ṽ = 2924, 2863, 1782, 1166, 1042
cm-1. MS (EI): m/z = 158 [M]+.
(ppm): 4.07 (dd, J = 12.2, 3.8 Hz, 1 H), 4.19 (dd, J = 10.2, 5.4 Hz,
1 H), 4.22 (dd, J = 12.2, 5.4 Hz, 1 H), 4.37 (dd, J = 9.6, 9.6 Hz, 1
H), 4.60-4.67 (m, 1 H), 6.92 (dd, J = 8.6, 1.0 Hz, 2 H), 7.01 (t, J
= 7.2 Hz, 1 H), 7.28-7.34 (m, 2 H). 13C NMR (100 MHz, CDCl3,
25 °C) δ (ppm): 44.9, 57.2, 66.5, 114.6, 121.9, 129.7, 157.7,
226.4. IR (neat): ṽ = 2923, 1597, 1487, 1459, 1236, 1036 cm-1.
MS (EI): m/z = 242 [M]+
4-10-5. Styrene carbonate (3f): Pale yellow solid (163 mg, 99%).
1H NMR (400 MHz, CDCl3, 25 °C) δ (ppm): 4.34 (dd, J = 8.0,
8.0 Hz, 1 H), 4.80 (dd, J = 8.4, 8.4 Hz, 1 H), 5.68 (t, J = 8.2 Hz, 1
H), 7.33-7.48 (m, 5 H). 13C NMR (100 MHz, CDCl3, 25 °C) δ
(ppm): 71.1, 77.9, 125.8, 129.2, 129.7, 135.7, 154.8. IR (KBr): ṽ
= 3036, 2982, 2921, 1790, 1168, 1068 cm-1. MS (EI): m/z = 164
[M]+.
A mixture of benzyl ether 22 (61.4 mg, 0.145 mmol) and 10%
palladium on charcoal (0.12 g) in dry ethanol (2 mL) was stirred
under a hydrogen atmosphere at room temperature for 6 h. The
reaction mixture was filtered through celite and the solvent
evaporated in vacuo to give the crude product, which was
purified by flash chromatography (30% Et2O/CH2Cl2) to give the
title compound 23 (44.0 mg, 91%) as a colourless oil; [Found: C,
64.6; H, 12.2. C18H41O3Si requires C, 64.81; H, 12.39%]; Rf
(30% Et2O/CH2Cl2) 0.43; [a]D20-1.9 (c 2.1, CHCl3); nmax (liquid
film) 3600–3100 (br), 1470, 1390, 1255, 1105 cm−1; dH (400
MHz CDC13) 3.79–3.56 (2H, m, CH2OSi), 3.79–3.56 (2H, m,
CH2OH), 3.46 (3H, s, OMe), 2.95 (1H, dd, J 7.0, 4.0 Hz,
CHOMe), 2.00–1.91 (1H, m, CHaHbCH2OSi), 1.91–1.83 (1H, m,
CHaHbCH2OSi), 1.81–1.73 (1H, m, CHMe), 1.35–1.27 (1H, m,
CHMe), 1.06–1.01 (3H, buried m, Me2CHSi), 1.04 (18H, br d, J
4.5 Hz, Me2CHSi), 0.97 (3H, d, J 7.0 Hz, CHMe), 0.93 (3H, d, J
7.0 Hz, CHMe); dC (100.6 MHz, CDCl3) 92.3, 66.7, 61.5, 60.9,
37.0, 34.4, 32.0, 18.0, 16.9, 15.3, 11.9; m/z (CI, NH3) 333 (30,
MH+), 257 (25), 159 (100), 141 (50), 109 (37%); HRMS (CI,
NH3): MH+, found 333.2825. C18H41O3Si requires 333.2825.
4-11. General procedure in protic solvent for five-membered
cyclic carbonate
The catalyst 1a•HI (14.0 mg, 0.05 mmol) was added to a solution
of epoxide (2g or 2h, 1 mmol) in 2-propanol (0.2 mL) at room
temperature. The atmosphere inside the flask was replaced with
CO2 (balloon, ca. 1 atm), and the reaction mixture was stirred at
25 °C. After 48-72 h, the mixture was diluted with ethyl acetate,
and washed with water. The aqueous phase was extracted twice
with ethyl acetate, and the combined organic layers were dried
over Na2SO4 and evaporated in vacuo. The residue was dried in
vacuo for 6 h at 30 °C to give corresponding cyclic carbonate (3g
or 3h).
4-11-1. Propyrene carbonate (3g): Pale yellow oil (93 mg, 91%).
1H NMR (400 MHz, CDCl3, 25 °C) δ (ppm): 1.43 (d, J = 6.4 Hz,
3 H), 3.97 (dd, J = 8.0, 7.2 Hz, 1 H), 4.50 (dd, J = 8.8, 7.6 Hz, 1
H), 4.75-4.85 (m, 1 H. 13C NMR (100 MHz, CDCl3, 25 °C) δ
(ppm): 19.3, 70.6, 73.5, 155.0. IR (neat): ṽ = 2989, 2937, 1790,
1183, 1052 cm-1. MS (EI): m/z = 102 [M]+.
Appendix A. Supplementary data
Supplementary data to this article can be found online at
References
4-11-2. 1,2-Hexylene carbonate (3h): Colorless oil (133 mg,
92%). H NMR (400 MHz, CDCl3, 25 °C) δ (ppm): 0.86 (t, J =
1
1. a) D. M. D'Alessandro, B. Smit, J. R. Long, Angew. Chem. Int. Ed.
49 (2010) 6058-6082; b) S. D. Schimel, J. I. House, K. A.
Hibbard, P. Bousquet, P. Ciais, P. Peylin, B. H. Braswell, M. J.
Apps, D. Baker, A. Bondeau, J. Canadell, G. Churkina, W.
Cramer, A. S. Denning, C. B. Field, P. Friedlingstein, C. Goodale,
M. Heimann, R. A. Houghton, J. M. Melillo, III, B. Moore, D.
Murdiyarso, I. Noble, S. W. Pacala, I. C. Prentice, M. R. Raupach,
P. J. Rayner, R. J. Scholes, W. L. Steffen, C. Wirth, Nature 414
(2001) 169-172.
6.8 Hz, 3 H), 1.22-1.45 (m, 4 H), 1.57-1.81 (m, 2 H), 4.01 (dd, J
= 8.2, 7.4 Hz, 1 H), 4.47 (dd, J = 8.0, 8.0 Hz, 1 H), 4.60-4.69 (m,
1 H). 13C NMR (100 MHz, CDCl3, 25 °C) δ (ppm): 13.7, 22.1,
26.3, 33.4, 69.3, 77.0, 155.0. IR (neat): ṽ = 2959, 2934, 2872,
1797, 1174, 1066 cm-1. MS (EI): m/z = 144 [M]+.
4-12. General procedure for five-membered cyclic
dithiocarbonate
The catalyst 1a•HI (14.0 mg, 0.05 mmol) was added to a solution
of 2a (150 mg, 1 mmol) and CS2 (152 mg, 2 mmol) in THF (0.2
mL) at room temperature. After the mixture was stirred at 25 °C
2. A.-A. G. Shaika, S. Sivaram, Chem. Rev. 96 (1996) 951-976.
3. M. North, R. Pasquale, C. Young, Green Chem. 12 (2010) 1514-
1539.
4. a) K. Soga, Y. Tazuke, S. Hosoda, S. Ikeda, J. Polym. Sci. Polym.
Chem. Ed. 15 (1977) 219-229; b) B. Ochiai, T. Endo, Prog.
Polym. Sci. 30 (2005) 183-215.