D. Matsuura et al. / Tetrahedron 64 (2008) 11686–11696
11695
(dd, J¼9.2, 5.5 Hz, 1H, CH2), 3.81 (dd, J¼9.2, 6.2 Hz, 1H, CH2), 2.63
(br s, 1H, OH), 2.17 (s, 3H, CH3); -anomer: 7.36–7.27 (m, 5H, ArH),
(20 mLꢂ3). The combined organic extracts were washed with
brine (20 mL), dried over anhydrous Na2SO4, and concentrated in
vacuo. The residue was purified by column chromatography (silica
b
d
6.22 (d, J¼8.4 Hz, 1H, NH), 5.42 (d, J¼4.4 Hz, 1H, CH), 4.81
(d, J¼11.9 Hz, 1H, PhCH2), 4.64 (dd, J¼5.9, 5.5 Hz, 1H, CH), 4.54 (d,
J¼11.9 Hz, 1H, PhCH2), 4.46 (dd, J¼5.5, 5.3 Hz, 1H, CH), 4.41 (ddd,
J¼6.6, 5.3, 4.6 Hz, 1H, CH), 4.07 (ddd, J¼8.4, 5.9, 4.7 Hz, 1H, CH), 3.74
(dd, J¼7.4, 4.6 Hz, 1H, CH2), 3.73 (dd, J¼7.4, 6.6 Hz, 1H, CH2), 2.04 (br
gel, hexane/AcOEt¼2/1) to give 18 (0.0178 g, 0.0444 mmol, 88%) as
23
a colorless oil. Rf¼0.25 (silica gel, hexane/AcOEt¼2/1); [
a
]
þ90.2
D
(c 1.0, CHCl3); IR (NaCl) 3271 (N–H), 2950 (C–H), 1736 (C]O), 1497
(C]C), 1109 (C–O) cmꢁ1 1H NMR (300 MHz, CDCl3)
;
d
6.05 (d,
s, 1H, OH), 2.01 (s, 3H, CH3); 13C NMR (75 MHz, CDCl3)
a-anomer:
J¼5.9 Hz, 1H, NH), 5.29 (d, J¼1.7 Hz, 1H, CH), 5.15 (dd, J¼5.8, 5.7 Hz,
1H, CH), 4.86 (d, J¼5.1 Hz, 1H, CH), 4.70 (dd, J¼6.4, 5.1 Hz, 1H, CH),
4.17 (ddd, J¼6.4, 5.9, 1.7 Hz, 1H, CH), 4.05 (dd, J¼9.5, 5.7 Hz, 1H,
CH2), 3.85 (dd, J¼9.5, 5.8 Hz, 1H, CH2), 2.23–2.20 (m, 2H, CH2), 2.09
(m, 1H, CH), 1.99 (s, 3H, CH3), 0.95 (d, J¼6.6 Hz, 6H, CH3), 0.86 (s,
d
170.2 (C), 137.0 (C), 128.5 (CH), 128.2 (CH), 128.1 (C), 104.5 (CH),
80.6 (CH), 80.3 (CH), 78.1 (CH), 72.7 (CH2), 71.6 (CH2), 58.7 (CH), 23.0
(CH3); -anomer: 170.2 (C), 137.0 (C), 128.6 (CH), 128.2 (CH), 128.1
b
d
(C), 96.8 (CH), 82.6 (CH), 78.3 (CH), 72.9 (CH2), 71.9 (CH2), 71.7 (CH),
58.7 (CH), 23.1 (CH3); HRMS (ESIþ) m/z calcd for C15H19NO5þNa:
316.1161, found: 316.1146.
9H, CH3), 0.97 (d, J¼6.6 Hz, 6H, CH3); 13C NMR (CDCl3)
d 172.0 (C),
170.0 (C), 104.5 (CH), 80.7 (CH), 79.7 (CH), 72.2 (CH), 71.1 (CH2),
59.0 (CH), 43.0 (CH2), 25.6 (CH), 25.5 (C), 23.1 (CH3), 22.3 (CH3),
22.2 (CH3), 17.8 (CH3), ꢁ4.7 (CH3), ꢁ5.3 (CH3); HRMS (ESIþ) m/z
calcd for C19H35NO6SiþNa: 424.2131, found: 424.2149.
4.2.20.2. TBS-protection. To a solution of the lactols (0.0320 g,
0.109 mmol) and imidazole (0.0260 g, 0.382 mmol) in DMF (1.0 mL)
was added tert-butyldimethylsilyl chloride (0.0444 g, 0.295 mmol).
After stirring for 3 h, the reaction mixture was quenched by addition
of H2O (3 mL) and extracted with AcOEt (10 mLꢂ3). The combined
organic extracts were washed with brine (10 mL), dried over anhy-
drous Na2SO4, and concentrated in vacuo. The residue was purified
by column chromatography (silica gel, hexane/AcOEt¼1/1) to give
4.2.22. Furanodictine B (2)
To a solution of 18 (0.0160 g, 0.0399 mmol) in THF (0.4 mL) was
added tetrabutylammonium fluoride (1.0 M solution in THF,
0.04 mL, 0.04 mmol). After stirring for 1 h, the reaction mixture was
quenched by addition of saturated aqueous NaHCO3 (1 mL) and
extracted with AcOEt (10 mLꢂ3). The combined organic extracts
were washed with brine (20 mL), dried over anhydrous Na2SO4, and
concentrated in vacuo. The residue was purified by column chro-
17 (0.0440 g, 0.108 mmol, 99%) as a colorless oil. Rf¼0.30 (silica gel,
25
hexane/AcOEt¼1/1); [
a]
þ78.4 (c 0.9, CHCl3); IR (NaCl) 3308 (N–
D
H), 2955 (C–H), 1659 (C]O), 1107 (C–O) cmꢁ1; 1H NMR (300 MHz,
CDCl3)
d
7.51–7.42 (m, 5H, ArH), 6.40 (d, J¼7.1 Hz, 1H, NH), 5.37 (d,
matography (silica gel, AcOEt) to give 2 (0.0110 g, 0.0383 mmol, 96%)
26
J¼1.3 Hz, 1H, CH), 4.97 (dd, J¼6.2, 4.6 Hz, 1H, CH), 4.95 (dd, J¼4.6,
4.4 Hz,1H, CH), 4.78 (d, J¼11.0 Hz,1H, PhCH2), 4.55 (d, J¼11.0 Hz,1H,
PhCH2), 4.22 (ddd, J¼7.1, 6.2, 1.3 Hz, 1H, CH), 4.06 (dd, J¼4.7, 4.4 Hz,
1H, CH), 3.94 (d, J¼4.7 Hz, 2H, CH2),1.79 (s, 3H, CH3), 0.91 (s, 9H, CH3),
as a colorless oil: Rf¼0.20 (AcOEt); [
a
]
þ104.8 (c 0.9, CHCl3); IR
D
(NaCl) 3413 (O–H), 3281 (N–H), 2939 (C–H), 1744 (C]O), 1659
(C]O), 1190 (C–O) cmꢁ1 1H NMR (300 MHz, CDCl3)
;
a
-anomer:
d
6.20 (d, J¼6.2 Hz,1H, NH), 5.24 (d, J¼4.0 Hz,1H, CH), 5.17 (dt, J¼6.2,
0.15 (s, 6H, CH3); 13C NMR (75 MHz, CDCl3)
d
170.1 (C),137.5 (C),128.5
5.0 Hz,1H, CH), 4.98 (t, J¼5.0 Hz, 1H, CH), 4.61 (dd, J¼6.2, 5.0 Hz, 1H,
CH), 4.22 (dt, J¼6.2, 4.0 Hz,1H, CH), 4.06 (dd, J¼9.5, 6.2 Hz,1H, CH2),
3.83 (dd, J¼9.5, 6.2 Hz,1H, CH2), 3.40 (br s,1H, OH), 2.26 (dd, J¼15.0,
7.3 Hz, 1H, CH2), 2.22 (dd, J¼15.0, 7.3 Hz, 1H, CH2), 2.12 (m, 1H, CH),
2.04 (s, 3H, CH3), 0.98 (d, J¼6.6 Hz, 3H, CH3), 0.96 (d, J¼6.6 Hz, 3H,
(CH),128.2 (CH),128.1 (C),103.4 (CH), 81.0 (CH), 80.6 (CH), 77.5 (CH),
73.1 (CH2), 72.8 (CH2), 58.0 (CH), 25.9 (C), 23.0 (CH3),17.9 (CH3), ꢁ4.6
(CH3), ꢁ5.2 (CH3); HRMS (ESIþ) m/z calcd for C21H33NO5SiþNa:
430.2026, found: 430.2051.
CH3);
b
-anomer:
d
6.18 (d, J¼7.9 Hz, 1H, NH), 5.55 (d, J¼5.0 Hz, 1H,
4.2.21. (1S,4S,5R,8R)-4-Acetamido-3-(tert-butyldimethylsilyloxy)-
2,6-dioxabicyclo[3.3.0]oct-8-yl isovalerate (18)
OH), 5.38 (dd, J¼5.3, 5.0 Hz, 1H, CH), 5.17 (dt, J¼6.2, 5.1 Hz, 1H, CH),
4.98 (dd, J¼5.1, 4.8 Hz, 1H, CH), 4.53 (dd, J¼5.3, 4.8 Hz, 1H, CH),
4.45 (dt, J¼7.9, 5.3 Hz,1H, CH), 4.08 (dd, J¼9.2, 6.2 Hz, 1H, CH2), 3.98
(dd, J¼9.2, 6.2 Hz, 1H, CH2), 2.28 (dd, J¼15.0, 7.3 Hz, 1H, CH2), 2.24
(dd, J¼15.0, 7.3 Hz, 1H, CH2), 2.12 (m, 1H, CH), 2.04 (s, 3H, CH3), 0.99
(d, J¼6.6 Hz, 3H, CH3), 0.97 (d, J¼6.6 Hz, 3H, CH3); 13C NMR (75 MHz,
4.2.21.1. Deprotection of benzyl group by hydrogenolysis. A solution
of 17 (0.0190 g, 0.0467 mmol) in ethyl acetate (1.0 mL) was hydro-
genated in the presence of 5% Pd on activated carbon (0.025 g) at
roomtemperature for12 h. The Pdcatalystwasremoved byfiltration
through a pad of Celite and washed with ethyl acetate (30 mL). The
filtrate was concentrated in vacuo and the resulting residue was
purified by column chromatography (silica gel, hexane/AcOEt¼1/2)
CDCl3)
(CH), 72.8 (CH), 70.7 (CH2), 59.2 (CH), 43.0 (CH2), 25.6 (CH), 23.1
(CH3), 22.4 (CH3), 22.3 (CH3); -anomer: 172.3 (C), 170.2 (C), 96.6
a-anomer: d 172.3 (C), 170.2 (C), 103.7 (CH), 80.3 (CH), 79.8
b
d
(CH), 80.7 (CH), 80.6 (CH), 73.4 (CH), 71.2 (CH2), 54.6 (CH), 43.0 (CH2),
25.6 (CH), 23.1 (CH3), 22.4 (CH3), 22.3 (CH3); HRMS (ESIþ) m/z calcd
for C13H21NO6þNa: 310.1267, found: 310.1268.
to give the corresponding alcohol (0.0147 g, 0.0463 mmol, 99%) as
25
a colorless oil. Rf¼0.40 (silica gel, hexane/AcOEt¼1/2); [
a
]
þ78.4 (c
D
0.9, CHCl3); IR (NaCl) 3415 (N–H), 3300 (O–H), 2930 (C–H), 1655
(C]O), 1109 (C–O) cmꢁ1 1H NMR (300 MHz, CDCl3)
;
d
6.34 (d,
Acknowledgements
J¼6.0 Hz, 1H, NH), 5.43 (s, 1H, CH), 4.82–4.75 (m, 2H, CH), 4.23 (m,
2H, CH), 4.00 (dd, J¼10.1, 2.6 Hz,1H, CH2), 3.90 (dd, J¼10.1, 3.7 Hz,1H,
CH2), 2.67 (br s, 1H, OH), 2.01 (s, 3H, CH3), 0.90 (s, 9H, CH3), 0.13 (d,
This work was supported in part by a Grant-in-Aid for Scientific
Research from Japan Society for the Promotion of Science. We ac-
knowledge Nanotechnology Network Project (Kyushu-area Nano-
technology Network) of the Ministry of Education, Culture, Sports,
Science and Technology (MEXT), Japan
J¼6.6 Hz, 6H, CH3); 13C NMR (75 MHz, CDCl3)
d 170.2 (C), 105.9 (CH),
81.9 (CH), 77.4 (CH), 76.1 (CH), 70.2 (CH2), 57.6 (CH), 25.6 (C), 23.2
(CH3), 17.9 (CH3), ꢁ4.7 (CH3), ꢁ5.3 (CH3); HRMS (ESIþ) m/z calcd for
C14H27NO5SiþNa: 340.1556, found: 340.1583.
4.2.21.2. Esterification with isovaleric acid. To a solution of the al-
cohol (0.0160 g, 0.0504 mmol), 4-dimethylaminopyridine (0.0062 mg,
0.0507 mmol), and 1-ethyl-3-(3-dimethylaminopropyl)carbodii-
mide hydrochloride (0.0193 mg, 0.101 mmol) in CH2Cl2 (0.3 mL)
was added isovaleric acid (0.0155 mg, 0.152 mmol) at room tem-
perature. After stirring for 2 h, the reaction mixture was quenched
by addition of H2O (2 mL) and extracted with ethyl acetate
References and notes
1. Kikuchi, H.; Saito, Y.; Komiya, J.; Takaya, Y.; Honma, S.; Nakahata, N.; Ito, A.;
Oshima, Y. J. Org. Chem. 2001, 66, 6982.
2. Maeda, Y.; Inouye, K.; Takeuchi, I. Dictyostelium A Model System for Cell and
Development Biology. Frontiers Science Series No. 21; Universal Academy.:
Tokyo, 1997.
3. Yoda, H.; Suzuki, Y.; Takabe, K. Tetrahedron Lett. 2004, 45, 1599.