Beilstein J. Org. Chem. 2018, 14, 2537–2544.
the reaction mixture was stirred at room temperature for 20 h. 3.07–2.99 (m, 6H), 2.04 (q, J = 6.8 Hz, 3H), 1.58 (q,
After completion of the reaction (TLC monitoring), the reac- J = 13.2 Hz, 3H) ppm; 13C NMR (100 MHz, CDCl3) δ 175.7,
tion mixture was quenched with sat. aq NH4Cl. Thereafter, the 141.7, 141.1, 136.4, 131.4, 128.1, 126.9, 125.6, 116.1, 49.1,
reaction mixture was diluted with EtOAc (10 mL) washed with 46.3, 35.5 ppm; HRMS (ESI, Q-ToF) m/z: [M + Na]+ calcd
water and brine (2 × 10 mL). Then, the aqueous layer was for C57H51N3O6·Na, 896.3670; found; 896.3678; IR (neat)
extracted with EtOAc (3 × 10 mL) and the combined organic
layers were dried over Na2SO4. The solvent was removed under
max: 2342, 1709, 1512, 1183, 919, 736 cm−1.
reduced pressure and the crude product was purified by silica Synthesis of trimerized product 19
gel column chromatography (65% EtOAc/petroleum ether) to Based on the earlier procedure of trimerization, compound 18
afford the trimerized product 11 (321 mg, 64%) as a colourless (500 mg, 1.27 mmol) was treated with SiCl4 (0.43 mL,
solid. Rf = 0.54 (6:4 EtOAc/petroleum ether); mp 203–206 °C; 3.83 mmol) in the presence of EtOH (8 mL) for 20 h to give the
1H NMR (400 MHz, CDCl3) δ 7.68 (d, J = 5.2 Hz, 6H), 7.66 (s, trimerized product 19 after silica gel (100–200 mesh) column
3H), 7.24 (d, J = 2.4 Hz, 6H), 6.28 (s, 6H), 3.51–3.44 (m, 12H), chromatography (50% EtOAc/petroleum ether) as a colourless
1.79 (d, J = 8.8 Hz, 3H), 1.61 (d, J = 8.8 Hz, 3H) ppm; solid (324 mg, 64%); Rf = 0.61 (4:6 EtOAc/petroleum ether);
13C NMR (125 MHz, CDCl3) δ 177.0, 141.8, 141.3, 134.8, mp 224–226 °C; 1H NMR (500 MHz, CDCl3) δ 7.56 (s, 3H),
131.4, 128.2, 127.2, 125.7, 52.4, 46.0, 45.7 ppm; HRMS (ESI, 7.51 (d, J = 8.0 Hz, 6H), 7.43 (d, J = 3.0 Hz, 6H), 7.37 (d,
Q-ToF) m/z: [M + H]+ calcd for C51H40N3O6, 790.2912; found, J = 3.0 Hz, 6H), 7.24–7.22 (m, 12H), 6.62 (d, J = 8.5 Hz, 6H),
790.2918; IR (neat) max: 2918, 1706, 1512, 1371, 1173, 4.92 (s, 6H), 3.41 (s, 6H) ppm; 13C NMR (125 MHz, CDCl3)
754 cm−1.
δ 176.3, 141.5, 141.4, 138.9, 128.2, 127.4, 127.1, 127.0, 125.3,
124.5, 47.2, 46.1 ppm; HRMS (ESI, Q-ToF) m/z: [M + Na]+
calcd for C78H51N3O6·Na, 1148.3670; found, 1148.3672;
IR (neat) max: 2318, 1266, 745, 707 cm−1.
Synthesis of ring open metathesis (ROM)
product 13
The solution of compound 10 (500 mg, 1.76 mmol) in dry
CH2Cl2 (25 mL) was degasified by ethylene and G-I (5 mol %) Synthesis of hexaallyl derivative 14
was added to the reaction mixture at rt. Further, the reaction To the solution of compound 12 (200 mg, 0.22 mmol) in an-
mixture was stirred for 48 h under ethylene atmosphere at rt. hydrous THF (15 mL) was added NaHMDS (2 mL of
After completion of the reaction (TLC monitoring), the solvent 1 M solution in THF, 1.93 mmol) at −75 °C and the reaction
was removed under reduced pressure. Later, the crude product mixture was stirred for 30 min under nitrogen atmosphere. Then
was purified by silica gel column chromatography allyl bromide (0.11 mL, 1.60 mmol) was added to the reaction
(30% EtOAc/petroleum ether) to obtain the ROM product 13 as mixture and stirred for 2 h at −75 °C. Later, the reaction mix-
a colourless solid (310 mg, 56%); Rf = 0.68 (4:6 EtOAc/petro- ture was stirred to room temperature for 10 h. After completion
leum ether); mp 143–145 °C; 1H NMR (400 MHz, CDCl3) of the reaction (TLC monitoring), the reaction mixture was
δ 8.03 (d, J = 8.4 Hz, 2H), 7.40 (d, J = 8.4 Hz, 2H), 6.12–6.03 quenched with 1 M aq HCl solution, and the aqueous layer was
(m, 2H), 5.20–5.15 (m, 4H), 3.43 (q, J = 2.0 Hz, 2H), 3.08–3.00 extracted by EtOAc (3 × 10 mL). Then the organic fraction was
(m, 2H), 2.60 (s, 3H), 2.08–2.02 (m, 1H), 1.57 (t, J = 6.4 Hz, washed with brine solution, dried over Na2SO4 and concen-
1H) ppm; 13C NMR (100 MHz, CDCl3) δ 197.2, 175.4, 136.7, trated. The crude residue was purified by silica gel column
136.2, 136.1, 129.2, 126.5, 116.3, 49.1, 46.4, 35.4, 26.8 ppm; chromatography (10% EtOAc/petroleum ether) to afford hexa-
HRMS (ESI, Q-ToF) m/z: [M + Na]+ calcd for C19H19NO3·Na, allyl derivative 14 as a colourless solid (199 mg, 78%).
332.1257; found, 332.1254; IR (neat) max: 2325, 1671, 1263, Rf = 0.60 (3:7 EtOAc/petroleum ether); mp 204–206 °C;
746 cm−1.
1H NMR (500 MHz, CDCl3) δ 7.71 (d, J = 5.5 Hz, 6H), 7.69 (s,
3H), 7.33 (d, J = 8.5 Hz, 6H), 6.08–5.96 (m, 12H), 5.28–5.13
(m, 24H), 2.77–2.66 (m, 18H), 2.04–2.00 (m, 3H), 1.65 (q,
Synthesis of trimerized compound 12
Based on the earlier procedure of trimerization, compound 13 J = 12.5 Hz, 3H) ppm; 13C NMR (125 MHz, CDCl3) δ 178.2,
(500 mg, 1.61 mmol) was treated with SiCl4 (0.55 mL, 141.9, 141.3, 136.5, 132.8, 131.5, 128.1, 127.1, 125.7, 120.3,
4.84 mmol) in the presence of EtOH (8 mL) for 16 h to afford 117.1, 59.9, 51.2, 36.6, 35.1 ppm; HRMS (ESI, Q-ToF) m/z:
trimerized product 12 after silica gel column chromatography [M + Na]+ calcd for C75H75N3O6·Na, 1136.5548; found,
(60% EtOAc/petroleum ether) as a colourless solid (254 mg, 1136.5544; IR (neat) max: 2345, 1671, 1263, 746 cm−1.
54%); mp 152–154 °C; Rf = 0.55 (5:5 EtOAc/petroleum ether);
1H NMR (400 MHz, CDCl3) δ 7.72 (d, J = 8.0 Hz, 6H), 7.70 (s, Synthesis of hexaallyl product 20
3H), 7.37 (d, J = 8.4 Hz, 6H), 6.15–6.07 (m, 6H), 5.19 (q, Based on the earlier procedure of allylation, compound 19
J = 8.4 Hz, 12H), 3.43 (dd, J1 = 2.0 Hz, J2 = 2.0 Hz, 6H), (336 mg, 0.29 mmol) was treated with NaHMDS (2.3 mL of
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