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K. Yagi et al. / Tetrahedron 62 (2006) 4933–4940
give a residue, which was purified by chromatography
(hexane/EtOAc) to furnish cis-acetate 7 exclusively (1.26 g,
77% from (1R)-1): [a]D24 ꢁ3 (c 1.19, CHCl3); IR (neat)
the excess reagent. The resulting mixture was filtered
through a pad of Celite with Et2O. The filtrate was washed
with brine three times to make the aqueous solution slightly
acidic (pH 4). The aqueous layer was extracted with EtOAc
three times. The combined extracts were dried (MgSO4) and
concentrated. The residue was purified by chromatography
(hexane/EtOAc) to afford acid 10 (1.09 g, 90%): [a]2D6 –43
1735, 1242, 1112 cmꢁ1 1H NMR (300 MHz, CDCl3)
;
d 1.04 (s, 9H), 1.20–1.62 (m, 11H), 2.03 (s, 3H), 2.45–
2.63 (m, 2H), 3.65 (t, J¼6.5 Hz, 2H), 5.57–5.66 (m, 1H),
5.75 (dt, J¼6, 2 Hz, 1H), 5.99 (d, J¼5.5 Hz, 1H), 7.32–
7.45 (m, 6H), 7.59–7.76 (m, 4H); 13C NMR (75 MHz,
CDCl3) d 19.3, 21.5, 25.8, 27.0, 27.8, 29.5, 32.6, 36.4,
36.7, 44.4, 64.0, 80.0, 127.6, 128.8, 129.6, 134.2, 135.7,
141.2, 171.1. Anal. Calcd for C29H40O3Si: C, 74.95; H,
8.68. Found: C, 74.85; H, 8.74.
1
(c 0.394, CHCl3); IR (neat) 3100, 1707, 1112 cmꢁ1; H
NMR (300 MHz, CDCl3) d 1.05 (s, 9H), 1.20–1.62 (m,
10H), 1.80–1.93 (m, 1H), 2.02 (dd, J¼15, 10 Hz, 1H),
2.12–2.32 (m, 2H), 2.37 (dd, J¼15, 5.5 Hz, 1H), 2.86–3.09
(m, 1H), 3.58 (t, J¼6.5 Hz, 2H), 5.66–5.88 (m, 2H), 7.19–
7.44 (m, 6H), 7.52–7.70 (m, 4H); 13C NMR (75 MHz,
CDCl3) d 19.4, 25.9, 27.0, 28.8, 29.7, 30.4, 32.7, 34.8,
37.2, 41.5, 43.3, 64.1, 127.6, 129.5, 131.2, 134.1, 134.3,
135.6, 179.5. Anal. Calcd for C29H40O3Si: C, 74.95; H,
8.68. Found: C, 74.83; H, 8.90.
4.2.3. (4S,1R)-4-[6-{(tert-Butyldiphenylsilyl)oxy}hexyl]-
2-cyclopenten-1-ol (8). To an ice-cold solution of acetate
7 (1.81 g, 3.89 mmol) in THF (16 mL), MeOH (8 mL),
and H2O (4 mL) was added LiOH$H2O (898 mg,
21.4 mmol). The mixture was stirred at room temperature
overnight and diluted with saturated NH4Cl and EtOAc
with stirring at room temperature. The layers were sepa-
rated, and the aqueous layer was extracted with EtOAc
two times. The combined extracts were dried (MgSO4)
and concentrated to leave an oil, which was purified by chro-
matography (hexane/EtOAc) to give alcohol 8 (1.57 g,
95%): [a]2D8 –12 (c 1.11, CHCl3); IR (neat) 3319, 1112,
4.2.6. Iodo-lactone 11. To an ice-cold solution of acid 10
(1.74 g, 3.74 mmol) in Et2O (13 mL) and THF (13 mL)
was added NaHCO3 (989 mg, 11.8 mmol) dissolved in
H2O (24 mL) and the mixture was stirred for 30 min. Then
an aqueous solution of I2 (1.99 g, 7.84 mmol) and KI
(3.91 g, 23.6 mmol) in H2O (12 mL) was added. The result-
ing dark brown mixture was stirred at room temperature for
16 h under the dark and poured into aqueous Na2S2O3 with
vigorous stirring. The mixture was extracted with EtOAc
three times. The combined extracts were dried (MgSO4)
and concentrated to give an oil, which was purified by chro-
matography (hexane/EtOAc) to furnish 11 (1.90 g, 86%):
[a]2D3 +2 (c 1.2, CHCl3); IR (neat) 1787, 1166, 1111,
701 cmꢁ1 1H NMR (300 MHz, CDCl3) d 1.05 (s, 9H),
;
1.17–1.65 (m, 12H), 2.44–2.60 (m, 2H), 3.65 (t, J¼6.5 Hz,
2H), 4.75–4.87 (m, 1H), 5.77 (dt, J¼5.5, 2 Hz, 1H), 5.88
(d, J¼5.5 Hz, 1H), 7.30–7.50 (m, 6H), 7.62–7.74 (m, 4H);
13C NMR (75 MHz, CDCl3) d 19.3, 25.8, 27.0, 27.9, 29.5,
32.6, 36.9, 40.6, 44.5, 64.0, 77.5, 127.7, 129.6, 133.0,
134.2, 135.7, 139.1. Anal. Calcd for C27H38O2Si: C,
76.72; H, 9.06. Found: C, 76.68; H, 9.19.
1
702 cmꢁ1; H NMR (300 MHz, CDCl3) d 1.05 (s, 9H),
1.22–1.42 (m, 7H), 1.48–1.72 (m, 4H), 2.09 (dd, J¼15,
6 Hz, 1H), 2.49 (dd, J¼18, 4 Hz, 1H), 2.59 (dd, J¼18,
10 Hz, 1H), 2.58–2.73 (m, 1H), 3.05–3.16 (m, 1H), 3.66 (t,
J¼6.5 Hz, 2H), 4.46 (d, J¼5 Hz, 1H), 5.27 (d, J¼6 Hz,
1H), 7.32–7.50 (m, 6H), 7.64–7.72 (m, 4H); 13C NMR
(75 MHz, CDCl3) d 19.4, 25.8, 27.0, 28.4, 28.5, 28.9, 29.6,
30.1, 32.6, 39.0, 40.3, 40.5, 64.0, 92.8, 127.6, 129.5,
134.1, 135.5, 176.4. Anal. Calcd for C29H39O3Si: C,
58.97; H, 6.66. Found: C, 58.98; H, 6.77.
4.2.4. (1S,2S)-2-([6-{(tert-Butyldiphenylsilyl)oxy}hexyl]-
4-cyclopentenyl)ethanal (9). A sealed glass tube containing
alcohol 8 (917 mg, 2.17 mmol), Hg(OAc)2 (162 mg,
0.508 mmol), ethyl vinyl ether (2.4 mL, 25 mmol),ꢀand ben-
zene (5 mL) was iꢀmmersed in an oil bath set at 190 C. After
70 h at 180–190 C, the solution was cooled to room tem-
perature and transferred with benzene to a flask containing
K2CO3 (701 mg, 5.07 mmol). The mixture was stirred for
30 min and filtered through a pad of Celite with EtOAc.
The filtrate was concentrated to give an oil, which was puri-
fied by chromatography (hexane/EtOAc) to give aldehyde 9
(944 mg, 97%): [a]2D5 –45 (c 1.39, CHCl3); IR (neat) 1726,
4.2.7. Lactone 12. To a solution of iodo-lactone 11 (165 mg,
0.279 mmol) in benzene (0.9 mL) were added Bu3SnH
(0.23 mL, 0.86 mmol) and AIBN (5 mg, 0.03 mmol). After
1 h of reflux, the reaction was quenched by addition of
NaF (59 mg, 1.41 mmol). The slurry was stirred at room
temperature for 30 min, and filtered through a pad of Celite
with EtOAc. The filtrate was concentrated, and a residue was
purified by chromatography (hexane/EtOAc) to afford 12
(126 mg, 97%): [a]2D4 –5.7 (c 0.53, CHCl3); IR (neat)
1
1112, 701 cmꢁ1; H NMR (300 MHz, CDCl3) d 1.05 (s,
9H), 1.18–1.61 (m, 10H), 1.94 (dd, J¼15, 9 Hz, 1H), 2.23
(ddd, J¼16, 9, 2 Hz, 1H), 2.28–2.33 (m, 1H), 2.39 (dd,
J¼15, 8 Hz, 1H), 2.49 (ddd, J¼16, 5, 2 Hz, 1H), 3.00–
3.12 (m, 1H), 3.65 (t, J¼6.5 Hz, 2H), 5.77 (s, 2H), 7.32–
7.46 (m, 6H), 7.63–7.75 (m, 4H), 9.79 (t, J¼2 Hz, 1H);
13C NMR (75 MHz, CDCl3) d 19.3, 25.8, 26.9, 28.7, 29.6,
30.7, 32.6, 37.2, 41.3, 41.6, 44.6, 64.0, 127.6, 129.6,
131.2, 134.1, 134.2, 135.6, 202.9. Anal. Calcd for
C29H40O2Si: C, 77.62; H, 8.99. Found: C, 77.54; H, 9.07.
1771, 1111, 703 cmꢁ1
;
1H NMR (300 MHz, CDCl3)
d 0.97 (s, 9H), 1.10–1.36 (m, 8H), 1.42–2.20 (m, 7H), 2.35
(dd, J¼19, 6 Hz, 1H), 2.42 (dd, J¼19, 10 Hz, 1H), 2.78–
2.92 (m, 1H), 3.58 (t, J¼6 Hz, 2H), 4.95 (t, J¼6 Hz, 1H),
7.33–7.43 (m, 6H), 7.63–7.69 (m, 4H); 13C NMR
(75 MHz, CDCl3) d 19.3, 25.7, 26.9, 28.5, 28.7, 28.9, 29.5,
30.6, 32.5, 33.1, 40.5, 42.8, 63.9, 86.2, 127.6, 129.6,
134.2, 135.6, 178.1. Anal. Calcd for C29H40O3Si: C,
74.95; H, 8.68. Found: C, 75.03; H, 8.72.
4.2.5. (1S,2S)-2-([6-{(tert-Butyldiphenylsilyl)oxy}hexyl]-
4-cyclopentenyl)acetic acid (10). To an ice-cold solution
of aldehyde 9 (1.18 g, 2.63 mmol) in acetone (26 mL) was
added Jones reagent (4 M solution) slowly until the color
of the reagent persisted (ca. 0.7 mL). After 10 min of stirring
at the same temperature, 2-propanol was added to destroy
4.2.8. Methyl ester 14. To an ice-cold solution of lactone 12
(52 mg, 0.11 mmol) in THF (0.72 mL), MeOH (0.24 mL),