Beilstein J. Org. Chem. 2015, 11, 1614–1623.
7.54 (d, J = 3.2 Hz, 1H), 3.58 (s, 1H), 3,49 (s, 9H), 1.88 (d, J = 7.02 (d, J = 7.3 Hz, 2H), 4.99 (d, J = 7.5 Hz, 2H), 3.55 (d, J =
11.3 Hz, 1H), 1.78 (s, 1H), 1.64 (s, 1H), 1.46 (s, 1H), 1.32 (s, 7.3 Hz, 6H), 3.35 (s, 1H) 1.89 (s, 2H), 1.48 (d, J = 4.5 Hz,
9H); 13C NMR (75 MHz, CD3OD) δ 164.76, 161.55, 139.89, 11H); mp >300 °C; [αD] −83.4 (c 0.01, MeOH); ESIMS m/z:
137.05, 121.25, 120.27, 118.11, 71.57, 56.59, 35.20, 32.47, [M]2+ calcd for C46H60AlClN4O22+, 381.21; found,
28.07, 23.83; mp 206–208 °C; [αD] −175 (c 0.01, MeOH); 372.22 (substitution of Cl by OH); 379.20 (substitution of Cl by
ESIMS m/z: [M]2+ calcd for C34H54N4O22+, 275.21; found, OMe).
275.21.
Aluminium–salen complex (10)
5,5'-((1E,1'E)-((1R,2R)-Cyclohexane-1,2-
diylbis(azanylylidene))bis(methanylylidene))bis(N-
benzyl-3-(tert-butyl)-4-hydroxy-N,N-dimethyl-
benzenaminium bromide) (8b)
Prepared as described in previous work [29]. 1H NMR
(400 MHz, DMSO-d6) δ 8.35 (s, 1H), 7.41 (d, J = 2.4 Hz, 1H),
7.36 (d, J = 2.4 Hz, 1H), 2.60 (d, J = 10.7 Hz, 1H), 1.99–1.90
(s, 1H), 1.53 (s, 9H), 1.40–1.20 (m, 3H), 1.29 (s, 9H).
To a solution of 7 (120 mg, 0.231 mmol) in dry acetonitrile
(5 mL) was added benzyl bromide (79 mg, 0.46 mmol). The Synthesis of cyclic carbonates
solution was stirred at room temperature for 24 hours. Diethyl All cyclic carbonate formations were carried out in autoclaves
ether (10 mL) was then added to the solution resulting in or, in case of 1 bar CO2 reactions, in sample vials with a
formation of a precipitate which was filtered and washed with balloon of CO2 attached to them. In both cases the reactions
ether to leave a bright yellow powder (165 mg, 78%). 1H NMR were magnetically stirred. After completion of the experiment,
(400 MHz, CDCl3) δ 9.00 (s, 1H), 8.80 (d, J = 3.1 Hz, 1H), the reaction mixture was analysed by 1H NMR spectroscopy
7.33–7.27 (m, 1H), 7.19–6.98 (m, 4H), 6.76 (d, J = 3.2 Hz, 1H), and passed through a pad of silica to separate the catalyst. In the
5.51–5.37 (s, 2H), 3.98–3.90 (m, 1H), 3.85 (d, J = 8.0 Hz, 6H), case of a 100% conversion, CH2Cl2 was used as the eluent, if
2.2–2.1 (m, 1H), 2.0–1.9 (m, 1H), 1.6–1.4 (m, 2H), 1.25 (s, the conversion was incomplete then column chromatography
9H); 13C NMR (101 MHz, DMSO-d6) δ 165.63, 162.37, was used to purify the compounds (SiO2, EtOAc/hexane, 1:3).
139.22, 134.33, 133.01, 130.73, 129.06, 128.87, 123.76, 122.83,
117.57, 72.26, 69.97, 53.21, 35.55, 32.51, 29.37, 29.04, 24.05; Styrene carbonate: 1H NMR (400 MHz, CDCl3) δ
mp 140–144 °C; [αD] 107 (c 0.05, MeOH); ESIMS m/z: [M]2+ 7.44–7.32 (m, 5H), 5.66 (t, J = 8.0 Hz, 1H), 4.82–4.73 (m, 1H),
calcd for C46H62N4O22+, 351.24; found, 351.24.
4.37–4.26 (m, 1H); 13C NMR (101 MHz, CDCl3) δ 155.00,
135.88, 129.80, 129.31, 126.00, 78.11, 71.28.
Aluminium–salen complex (1)
To a solution of 8a (113 mg, 0.14 mmol) in dry acetonitrile 4-Chlorostyrene carbonate: 1H NMR (400 MHz, CDCl3) δ
(5 mL) under argon was added diethylaluminum chloride 7.48–7.25 (m, 4H), 5.65 (t, J = 8.0 Hz, 1H), 4.79 (t, J = 8.2 Hz,
(0.14 mL, 1 M solution in hexane). The reaction mixture was 1H), 4.29 (dd, J = 8.6, 7.9 Hz, 1H); 13C NMR (101 MHz,
heated at reflux for 3 hours. The solvent was evaporated under CDCl3) δ 154.65, 135.85, 134.35, 129.59, 127.37, 77.34, 71.10.
reduced pressure to give a dark yellow powder (95 mg, 78%)
which was used without any additional purification. 1H NMR 3-Chloropropylene carbonate: 1H NMR (400 MHz, CDCl3) δ
(400 MHz, DMSO-d6) δ 8.46 (s, 1H), 8.10 (s, 1H), 7.66 (s, 1H), 5.02–4.93 (m, 1H), 4.60–4.53 (m, 1H), 4.37 (dd, J = 8.9,
3.55 (s, 9H), 3.38 (s, 1H), 2.55 (s, 1H), 1.94 (s, 1H), 1.50 (s, 5.7 Hz, 1H), 3.82–3.67 (m, 2H); 13C NMR (101 MHz, CDCl3)
9H), 1.44 (s, 1H), 1.33 (s, 1H); mp >300 °C; [αD] −109.5 (c δ 154.49, 74.48, 67.06, 44.03.
0.05, MeOH); ESIMS m/z: [M]2+ calcd for C34H52AlClN4O22+,
305.18; found, 296.19 (substitution of Cl by OH); 303.20 3-Phenoxypropylene carbonate: 1H NMR (400 MHz, CDCl3)
(substitution of Cl by OMe).
δ 7.37–6.84 (m, 5H), 5.08–4.94 (m, 1H), 4.63–4.46 (m, 2H),
4.30–4.06 (m, 2H); 13C NMR (101 MHz, CDCl3) δ 157.83,
154.76, 129.78, 122.08, 114.69, 74.20, 66.95, 66.32.
Aluminium–salen complex (2)
To a solution of 8b (140 mg, 0.163 mmol) in dry acetonitrile
(5 mL) under argon was added diethylaluminum chloride Propylene carbonate: 1H NMR (400 MHz, CDCl3) δ
(0.17 mL, 1 M solution in hexane). The reaction mixture was 4.92–4.67 (m, 1H), 4.64–4.38 (m, 1H), 4.07–3.89 (m, 1H),
refluxed for 3 hours. Then, the solvent was evaporated under 1.47–1.36 (m, 3H); 13C NMR (101 MHz, CDCl3) δ 155.22,
reduced pressure to give a dark yellow powder (136 mg, 91%) 73.74, 70.78, 19.45.
which was used without any additional purification. 1H NMR
(400 MHz, DMSO-d6) δ 8.33 (s, 1H), 7.83 (d, J = 3.0 Hz, 1H), 1,2-Hexylene carbonate: 1H NMR (400 MHz, CDCl3) δ
7.47 (t, J = 8.6 Hz, 1H), 7.40 (s, 1H), 7.28 (t, J = 7.7 Hz, 2H), 4.74–4.59 (m, 1H), 4.53–4.43 (m, 1H), 4.02 (dt, J = 9.9, 4.9 Hz,
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