Molecules 2020, 25, 692
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The resulting mixture was stirred cold with an ice-bath for 30 min. An indicative color change was
observed after this time. Water (10 mL) was then added followed by extraction with dichloromethane
(3
×
20 mL). Combined organic layers were dried (Na2SO4), filtered and concentrated to afford an oil
which was purified through silica gel column.
(2R,3R,4S,5R)-2,4-bis(3,4-dimethoxyphenyl)-3,5-dimethyltetrahydrofuran 1a and (2R,3R,4S,5S)-2,4
-bis(3,4-dimethoxyphenyl)-3,5-dimethyltetrahydrofuran 2a. (156 mg, 75%) (hexane/ethyl acetate,
1
75/25 and 60/40). 1a: H NMR (300 MHz, CDCl3)
δ
7.00 (m, 2H), 6.86 (m, 2H), 6.72 (m, 2H), 4.46 (m,
1H), 3.92 (s, 3H), 3.87 (s, 3H), 3.18 (dd, J = 9.6, 8.5 Hz, 1H), 2.32 (m, 1H), 1.05 (d, J = 6.5 Hz, 3H), 0.97 (d,
J = 6.5 Hz, 3H) ppm; 13C NMR (75 MHz, CDCl3) d 149.2, 149.0, 148.8, 148.0, 134.3, 132.2, 120.8, 118.7,
112.4, 111.3, 111.2, 109.8, 87.7, 77.6, 77.4, 56.8, 56.2, 56.1, 56.0, 46.8, 19.1, 15.3 ppm. HRMS (ESI) calcd for
1
C22H28O2Na (M + Na+) 395.1834, found 395.1831). 2a: H NMR (300 MHz, CDCl3)
δ
6.89 (m, 2H), 6.76
(m, 2H), 6.64 (m, 2H), 4.49 (d, J = 9.4 Hz, 1H), 4.22 (dq, J = 12.0, 6.0 Hz, 1H), 3.85 (s, 3H), 3.81 (s, 3H),
3.80 (s, 3H), 3.79 (s, 3H), 2.46 (dd, J = 11.0, 9.5 Hz, 1H), 2.32 (m, 1H), 1.22 (d, J = 6.0 Hz, 3H), 0.86 (d,
J = 6.5 Hz, 5H) ppm.
(2R,3S,4R,5R)-3-(3,4-dimethoxyphenyl)-2,4-dimethyl-5-phenyltetrahydrofuran1band(2R,3S,4R,5S)
-3-(3,4-dimethoxyphenyl)-2,4-dimethyl-5-phenyltetrahydrofuran 2b. (108 mg, 62%) (hexanes/ethyl
1
acetate, 75/25 and 60/40). H NMR (300 MHz, CDCl3) d 7.29–7.45 (m, 5H), 6.68–6.82 (m, 3H), 4.46 (m,
1H), 4.49 (d, J = 9.1 Hz, 1H), 3.86 (s, 3H), 3.84 (s, 3H), 3.18 (dd, J = 9.6, 8.2 Hz, 1H), 2.31 (m, 1H), 1.05
(d, J = 6.5 Hz, 3H), 0.97 (d, J = 6.5 Hz, 3H) ppm; 13C NMR (100 MHz, CDCl3) d 148.8, 147.5, 141.5,
131.9, 128.2, 127.6, 126.0, 120.6, 111.9, 111.0, 87.5, 56.6, 55.7, 47.0, 18.8, 15.0 ppm. HRMS (ESI) calcd for
1
C20H24O3Na (M + Na+) 335.1623, found 335.1625. 2b: H NMR (400 MHz, CDCl3)
δ 7.39–7.20 (m, 5H),
6.62–6.77 (m, 3H), 4.54 (d, J = 9.4 Hz, 1H), 4.29–4.17 (m, 1H), 3.80 (s, 3H), 3.79 (s, 3H), 2.47 (dd, J = 11.1,
9.5 Hz, 1H), 2.18 (m, 1H), 1.22 (d, J = 6.0 Hz, 3H), 0.87 (d, J = 6.5 Hz, 3H) ppm.
(2S,3R,4S,5R)-2-(3,4-dimethoxyphenyl)-3-methyl-4,5-diphenyltetrahydrofuran 1c. (31 mg, 15%)
1
(hexanes/ethyl acetate, 75/25 and 60/40). H NMR (500 MHz, CDCl3) d 6.56–6.79 (m, 6H), 6.90–6.93 (m,
2H), 7.19–7.33 (m, 5H), 4.04 (d, J = 9.6 Hz,1H), 3.88 (d, J = 9.2 Hz, 1H), 3.82 (s, 3H), 3.70–3.79 (m, 1H),
3.75 (s, 3H), 2.13 (m, 1H), 0.96 (d, J = 6.4 Hz, 3H) ppm; 13C NMR (100 MHz, CDCl3) d 149.1, 147.7,
143.2, 139.9, 138.5, 137.5, 129.9, 129.3, 128.9, 127.2, 126.2, 126.1, 122.1, 112.2, 111.0, 78.0, 77.2, 56.0, 55.9,
53.7, 43.3, 16.0 ppm. HRMS (ESI) calcd for C20H24O3Na (M + Na+) 397.1780, found 397.1779.
(2R,3S,5R)-3-(3,4-dimethoxyphenyl)-2-methyl-5-phenyltetrahydrofuran 1d.
(95 mg, 57%)
1
(hexanes/ethyl acetate, 75/25 and 70/30). H NMR (300 MHz, CDCl3)
δ 7.63–7.17 (m, 8H), 6.96–6.62 (m,
5H), 5.23 (dd, J = 12.0, 5.6 Hz, 1H), 5.07 (dd, J = 9.5, 6.7 Hz, 1H), 4.52–4.39 (m, 1H), 4.24 (dq, J = 9.1, 6.0
Hz, 1H), 4.12 (dq, J = 8.8, 6.0 Hz, 1H), 3.62 (dd, J = 15.8, 7.8 Hz, 1H), 3.06 (ddd, J = 11.6, 9.2, 6.8 Hz, 1H),
2.94 (q, J = 8.9 Hz, 1H), 2.78 (dd, J = 12.5, 6.5 Hz, 1H), 2.74 (dd, J = 12.6, 2.2 Hz, 1H), 2.60 (t, J = 8.7 Hz,
1H), 2.56 (t, J = 8.7 Hz, 1H), 2.40 (dd, J = 8.8, 5.5 Hz, 1H), 2.35 (dd, J = 8.8, 5.4 Hz, 1H), 2.18 (dt, J = 22.1,
11.1 Hz, 1H), 2.25 (m, 1H), 1.40 (d, J = 6.0 Hz, 2H), 1.36 (d, J = 6.0 Hz, 1H), 1.00 (d, J = 6.4 Hz, 1H); 13
C
NMR (75 MHz, CDCl3) d 149.1, 149.1, 148.7, 148.0, 147.9, 147.6, 143.8, 143.6, 142.7, 128.5, 128.4, 128.4,
125.8, 125.7, 125.6, 119.6, 119.5, 111.7, 111.4, 111.4, 110.9, 110.8, 110.7, 82.8, 82.3, 80.1, 79.9, 79.8, 78.5,
55.9, 55.9, 55.8, 54.1, 51.8, 48.6, 44.7, 43.8, 41.1, 19.6, 19.1, 18.0 ppm. HRMS (ESI) calcd for C20H24O3Na
(M + Na+) 321.1468, found 321.1468.
(2R,3S,4R,5R)-3-(3,4-dimethoxyphenyl)-2,4-dimethyl-5-(2,4,5 trimethoxyphenyl)tetrahydrofuran
1
1e. (92 mg, 41%) (hexanes/ethyl acetate, 75/25 and 60/40). H NMR (300 MHz, CDCl3) d 7.07 (s, 1H),
6.73 (s, 1H), 6.62–6.67 (m, 2H), 6.46 (s, 1H), 4.86 (d, J = 9.0 Hz,1H), 4.36 (dq, J = 8.2, 6.5 Hz, 1H), 3.82 (s,
3H), 3.80 (s, 3H), 3.79 (s, 3H), 3.78 (s, 3H), 3.73 (s, 3H), 3.09 (dd, J = 9.1, 8.4 Hz, 1H), 2.31 (m, 1H), 0.98
(d, J = 6.6 Hz, 3H), 0.89 (d, J = 6.5 Hz, 3H) ppm; 13C NMR (75.5 MHz, CDCl3) d 151.8, 149.0, 148.8,
147.7, 143.4, 132.4, 97.7, 81.0, 77.2, 56.9, 56.7, 56.5, 56.2, 55.9, 55.9, 46.5, 18.8, 15.4 ppm. HRMS (ESI)
calcd for C23H30O6Na (M + Na+) 425.1940, found 425.1939.