Zhang et al.
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CH2Cl2 (100 mL×3). The combined organic layers
were dried over anhydrous MgSO4 and concentrated.
The residue was purified by silica gel column chroma-
tography with petroleum ether/ethyl acetate (V∶V=
30∶1) to give 11 (3.77 g, 51%) as a yellow oil. [α]D24
158.2, 133.8, 117.7, 107.7, 97.7, 72.2, 55.9, 55.5, 47.5,
41.4, 32.8, 27.1, 22.8, 22.4, 20.1; ESI-MS m/z: 321 ([M
+H]+); ESI-HRMS calcd for C18H24O5Na [M+Na]+
343.1521, found 343.1528.
1
Synthesis of (S)-dihydroresorcylide (1a)
+22.1 (c 1.2, MeOH); H NMR (300 MHz, CDCl3) δ:
Iodine (759 mg, 2.16 mmol) was added to a mixture
of aluminium (109 mg, 4.20 mmol) in anhydrous ben-
zene (6 mL). The mixture was refluxed for 0.5 h and
cooled to 0 ℃, then TBAI (3 mg) and compound 1b
(30 mg, 0.09 mmol) in benzene (3 mL) were added. The
mixture was stirred for 15 min at 0 ℃, then quenched
with 2 mol•L−1 HCl (7 mL) at 0 ℃ and extracted with
EtOAc (30 mL×3). The organic phase was washed
with saturated NaHCO3 (10 mL×3) and brine (10 mL),
dried over anhydrous Na2SO4 and concentrated in vacuo.
The residue was purified by column chromatography
with petroleum ether/ethyl acetate (V∶V=2∶1) as
eluent to afford the target molecule 1a (23.33 mg, 85%)
6.92 (dq, J=13.7, 6.8 Hz, 1H), 6.38 (d, J=2.0 Hz, 1H),
6.29 (d, J=2.0 Hz, 1H), 6.18 (dd, J=13.7, 1.8 Hz, 1H),
5.80 (ddt, J=16.7, 1.4 Hz, 1H), 5.08-5.17 (m, 1H),
5.0 (dd, J=16.7, 1.4 Hz, 1H), 4.95 (d, J=9.8, 1.4 Hz,
1H), 3.86 (d, J=15.8, 1H), 3.79 (s, 3H), 3.78 (d, J=
15.8 Hz, 1H), 2.06 (t, J=6.7 Hz, 2H), 1.86 (dd, J=6.8,
1.4 Hz, 3H), 1.66-1.74 (m, 1H), 1.59-1.65 (m, 1H),
1.52-1.58 (m, 1H), 1.41-1.51 (m, 1H), 1.29 (d, J=
6.2 Hz, 3H); 13C NMR (125 MHz, CDCl3) δ: 196.3,
167.7, 161.5, 158.6, 143.7, 138.6, 135.1, 130.7, 117.3,
114.7, 106.8, 97.7, 71.9, 55.8, 55.5, 45.5, 35.5, 33.6,
24.7, 20.2, 18.4; ESI-MS m/z: 361 ([M +H] + );
ESI-HRMS calcd for C21H28O5Na [M+Na]+ 383.1834,
found 383.1837.
1
as a white solid. [α]D24 −40.0 (c 0.8, MeOH); H NMR
(300 MHz, CD3OD) δ: 6.25 (d, J=2.3 Hz, 1H), 6.11 (d,
J=2.3 Hz, 1H), 5.12 (m, 1H), 4.70 (d, J=18.8 Hz, 1H),
3.79 (d, J=18.8 Hz, 1H), 2.69 (dd, J=16.4, 9.9 Hz,
1H), 2.33 (dd, J=16.4, 9.9 Hz, 1H), 2.02 (m, 1H), 1.81
(m, 1H), 1.64 (m, 2H), 1.52 (m, 4H), 1.29 (d, J=6.2 Hz,
3H); 13C NMR (125 MHz, CD3OD) δ: 211.7, 172.4,
166.6, 163.8, 140.2, 113.7, 106.6, 102.9, 74.5, 51.7,
42.5, 32.7, 28.2, 22.2, 22.1, 19.4; ESI-MS m/z: 293 ([M
+H]+); ESI-HRMS calcd for C16H20O5Na [M+Na]+
315.1208, found 315.1212.
Synthesis of trans-resorcylide dimethyl ether (2b)
A solutions of diene 11 (1.00 g, 2.78 mmol) and the
Grubbs II catalyst (47.13 mg, 0.056 mmol) in CH2Cl2
(600 mL) was heated to reflux for 2 h. The solution was
concentrated and filtered through a silica pad to give the
crude product which was purified by silica gel column
chromatography with petroleum ether/ethyl acetate (V∶
V=30∶1) to give compound 2a (0.56 g, 64%) as a
1
colorless oil. [α]D24 +34.2 (c 0.9, MeOH); H NMR
(300 MHz, CDCl3) δ: 6.82-6.98 (m, 1H), 6.54 (d, J=
2.3 Hz, 1H), 5.93 (d, J=16.5 Hz, 1H), 5.21 (m, 1H),
4.59 (d, J=12.0 Hz, 1H), 3.80 (s, 3H), 3.77 (s, 3H),
3.28 (d, J=12.0 Hz, 1H), 2.21-2.37 (m, 1H), 1.77-
1.91 (m, 2H), 1.58-1.75 (m, 1H), 1.36 (d, J=6.3 Hz,
3H), 1.20-1.32 (m, 1H), 0.79-0.94 (m, 1H); 13C
NMR (125 MHz, CDCl3) δ: 199.2, 168.9, 161.6, 158.4,
150.4, 134.7, 131.0, 117.6, 106.5, 98.1, 72.5, 56.0, 55.6,
42.7, 34.1, 31.9, 24.8, 20.7; ESI-MS m/z: 319 ([M+
H]+); ESI-HRMS calcd for C18H22O5Na [M+Na]+
341.1365, found 341.1357.
Acknowledgement
This research work was financially supported by the
Natural Science Foundation of China (Nos. 21021063,
81273430), the National Marine “863” Project (Nos.
2011AA09070102 and 2013AA092902) and the
SKLDR/SIMM Projects (No. SIMM1203ZZ-03). We
also thank Professor Minghua Xu (SIMM-CAS) for
helpful discussion in preparation of this manuscript.
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