removed to give a solid residue (300 mg). Chromatography on silica
gel (50 g) using ethyl acetate–hexane (1 : 1) as eluent afforded the
cyclohexanediol 22 (130 mg, 43%), mp 141–142 ◦C (from toluene);
mmax(CHCl3)/cm−1 3611 (OH); dH (400 MHz, CDCl3) 1.02 [9H, s,
C(CH3)3], 1.60 (1H, br. s, OH), 1.61 (1H, dt, J 14.3 and 2 × 4.1 Hz,
6ꢀ-HA), 1.75 (1H, td, J 2 × 13.1 and 4.5 Hz, 3ꢀ-HA), 2.07 (1H, br. s,
OH), 2.08–2.17 (2H, m, 2ꢀ-H and 3ꢀ-HB), 2.22 (1H, td, J 2 × 14.3
and 2.7 Hz, 6ꢀ-HB), 3.28 (1H, dt, J 9.9 and 2 × 4.1 Hz, 1ꢀ-H), 3.50–
3.61 (2H, m, 1ꢀꢀ-HA and 4ꢀ-H), 3.61 (3H, s, 1-OCH3), 3.67 (1H, t,
J 2 × 10.3 Hz, 1ꢀꢀ-HB), 3.78 (3H, s, Ar–OCH3), 3.88–3.92 (1H, m,
5ꢀ-H), 4.65 (2H, s, Ar–CH2–O), 6.72–6.78 (2H, m, PMB Ar-H),
7.00–7.06 (2H, m, PMB Ar-H), 7.28–7.45 (7H, m, 3-H and TPS
Ar-H) and 7.56–7.65 (4H, m TPS Ar-H); dC (100 MHz, CDCl3)
19.2 [C(CH3)3], 26.9 [C(CH3)3], 29.2 (C-3ꢀ), 29.7 (C-1ꢀ), 30.4 (C-
6ꢀ), 40.5 (C-2ꢀ), 51.2 (1-OCH3), 55.3 (Ar–OCH3), 62.1 (C-1ꢀꢀ), 67.4
(C-4ꢀ), 69.4 (C-5ꢀ), 75.5 (Ar–CH2–O), 111.2 (C-2), 114.0, 127.8 and
129.2 (PMB Ar-C), 127.4(9) and 127.5(6), 129.4 (7) and 129.5(1),
133.9(6) and 134.1(1), 135.6 (TPS Ar-C), 158.5 (C-3), 160.0 (PMB
Ar-C) and 168.9 (C-1); (Found: C, 69.2; H, 7.4%, M+ − C4H9,
547.2133. Calc. for C35H44O7Si: C, 69.5; H, 7.4%, C31H35O7Si: M,
547.2143).
10 min and borane–dimethylsulfide complex (1.0 M solution in
dichloromethane, 1.9 cm3) was added. The solution was warmed
to 25 ◦C and stirred for 18 h. The reaction was acidified with 1 M
HCl (0.5 cm3) and the solution was stirred vigorously for 2 h. Solid
sodium carbonate was added until the pH of the aqueous portion
reached 10. Magnesium sulfate was added to dry the solution
and the mixture was filtered through a sintered glass funnel
and rinsed with dichloromethane. The filtrate and rinsings were
combined and the solvent was removed under reduced pressure
to give a crude product (210 mg). Chromatography on silica gel
(25 g) using ethyl acetate–hexane (3 : 2) as eluent yielded the
lactone 24 (135 mg, 67%) as an oil, mmax(CHCl3)/cm−1 1731 (CO);
dH (400 MHz, CDCl3) 1.06 [9H, s, C(CH3)3], 1.46–1.68 (4H, m,
5-HA, 3ꢀ-H2 and 2ꢀ-H), 1.68–1.77 (1H, m, 5-HB), 1.85 (1H, br. s,
OH), 2.07–2.25 (2H, m, 3-HA and 4-H), 2.59 (1H, ddd, J 16.7,
5.5 and 1.8 Hz, 3-HB), 3.54–3.66 (4H, m, 1ꢀ-H2 and 4ꢀ-H2), 4.13
(1H, td, J 2 × 11.3 and 3.6 Hz, 6-HA), 4.31 (1H, ddd, J 11.3,
4.9 and 3.6 Hz, 6-HB), 7.34–7.50 (6H, m, Ar-H) and 7.58–7.67
(4H, m Ar-H); dC (100 MHz, CDCl3) 19.2 [C(CH3)3], 26.5 (C-5),
26.9 [C(CH3)3], 31.2 (C-3ꢀ), 32.8 (C-4), 33.9 (C-3), 41.8 (C-2ꢀ), 60.7
and 63.7 (C-1ꢀ and C-4ꢀ), 68.6 (C-6), 127.7(3) and 127.8(1), 130.0,
132.9(2) and 132.9(8), 135.5(6) and 135.5(9) (Ar-C) and 171.5 (C-
2); (Found: M+, 426.2216. Calc. for C25H34O4Si: M, 426.2224).
Methyl (2E,3S*,4R*)-4-tert-butyldiphenylsilanyloxymethyl-3-
formylmethyl-2-p-methoxybenzyloxymethylene-6-oxohexanoate
(23)
(2ꢀR*,4R*)-4-(1-tert-Butyldiphenylsilanyloxy-4-
phenylselanylbutan-2-yl)tetrahydropyran-2-one (25)
Lead tetraacetate (150 mg, 0.34 mmol) was added over a 30 min
period to a stirred solution of 22 (160 m◦g, 0.26 mmol) in toluene
(5 cm3). The solution was stirred at 25 C for a further 30 min,
after which ethylene glycol (2 drops) was added and the solution
was stirred for 10 min. The resulting mixture was filtered through
Celite and the solvent was removed to give an oily residue (200 mg).
Chromatography on silica gel (20 g) using ethyl acetate–hexane
(1 : 9) as eluent afforded the unstable dialdehyde 23 (70 mg, 45%)
as an oil, mmax(CHCl3)/cm−1 1722 (CO); dH (400 MHz, CDCl3) 1.04
[9H, s, C(CH3)3], 2.28 (1H, ddd, J 17.0, 4.3 and 2.1 Hz, 5-HA), 2.34
(1H, ddd, J 16.2, 4.3 and 1.3 Hz, 1ꢀꢀ-HA), 2.45 (1H, ddd, J 17.0,
8.2 and 2.1 Hz, 5-HB), 2.52–2.62 (1H, m, 4-H), 2.70 (1H, ddd, J
16.2, 10.6 and 3.3 Hz, 1ꢀꢀ-HB), 3.43–3.52 (1H, m, 3-H), 3.58 (1H,
dd, J 5.3 and 10.8 Hz, 1ꢀꢀꢀ-HA), 3.66 (3H, s, 1-OCH3), 3.70 (1H,
dd, J 10.8 and 3.2 Hz, 1ꢀꢀꢀ-HB), 3.81 (3H, s, Ar-OCH3), 4.91 (2H, s,
Ar-CH2–O), 6.86–6.96 (2H, m, PMB Ar-H), 7.20–7.24 (2H, m,
PMB Ar-H), 7.35–7.46 (6H, m, TPS Ar-H), 7.51 (1H, s, 1ꢀ-H),
7.58–7.70 (4H, m TPS Ar-H), 9.43 (1H, dd, J 3.3 and 1.3 Hz,
2ꢀꢀ-H) and 9.55 (1H, t, J 2 × 2.1 Hz, 6-H); dC (100 MHz, CDCl3)
19.2 [C(CH3)3], 26.8 [C(CH3)3], 30.7 (C-3), 38.0 (C-4), 44.6 (C-
1ꢀꢀ), 44.8 (C-5), 51.3 (1-OCH3), 55.3 (Ar–OCH3), 64.1 (C-1ꢀꢀꢀ), 75.5
(Ar–CH2–O), 110.1 (C-2), 114.2, 127.5 and 129.6 (PMB Ar-C),
127.7(2) and 127.7(5), 129.7(8) and 129.8(4), 133.0, 135.5(9) and
135.6(3) (TPS Ar-C), 159.3 (C-2ꢀ), 160.0 (PMB Ar-C), 167.7 (C-
1), 202.0 (C-2ꢀꢀ) and 202.3 (C-6); (Found: M+ 602.2678. Calc. for
C35H42O7Si: M, 602.2689).
Phenylselenocyanate (538 mg, 2.95 mmol) in tetrahydrofuran
(5 cm3) and tri-n-butylphosphine (0.98 cm3, 3.94 mmol) were
added sequentially to a stirred solution of 24 (840 mg, 1.97 mmol)
in tetrahydrofuran (15 cm3). The resulting solution was stirred
at 25 ◦C for 30 min, after which the solvent was removed
under reduced pressure to give a crude mixture which was
chromatographed directly on silica gel (60 g) using ethyl acetate–
hexane (2 : 3) as eluent to yield phenyl selenide 25 (970 mg, 87%) as
an oil, mmax(CHCl3)/cm−1 1730 (CO); dH (400 MHz, CDCl3) 1.03
[9H, s, C(CH3)3], 1.42–1.79 (5H, m, 5-H2, 3ꢀ-H2 and 2ꢀ-H), 2.06–
2.21 (2H, m, 3-HA and 4-H), 2.51–2.58 (1H, m, 3-HB), 2.65 (1H,
ddd, J 12.1, 8.5 and 7.3 Hz, 4ꢀ-HA), 2.84 (1H, ddd, J 12.1, 8.8 and
5.2 Hz, 4ꢀ-HB), 3.58 (1H, dd, J 10.9 and 5.0 Hz, 1ꢀ-HA), 3.62 (1H,
dd, J 10.9 and 4.2 Hz, 1ꢀ-HB), 4.06–4.14 (1H, m, 6-HA), 4.29 (1H,
ddd, J 11.3, 4.7 and 3.8 Hz, 6-HB), 7.15–7.25 (4H, m, Ar-H), 7.32–
7.45 (7H, m, Ar-H) and 7.55–7.66 (4H, m, Ar-H); dC (100 MHz,
CDCl3) 19.2 [C(CH3)3], 25.6 (C-5), 26.6 (C-3ꢀ), 27.0 [C(CH3)3],
28.1 (C-4ꢀ), 32.7 (C-4), 34.1 (C-3), 44.6 (C-2ꢀ), 62.6 (C-1ꢀ), 68.7
(C-6), 127.8(3) and 127.8(4), 129.9(2) and 129.9(5), 133.1(1) and
133.1(8), 135.6(0) and 135.6(2) (TPS Ar-C), 127.1, 129.1, 129.8
and 132.8 (PhSe Ar-C) and 171.3 (C-2); (Found: M+ − C4H9,
509.1032. Calc. for C27H29O380SeSi: M, 509.1043).
(2ꢀR*,4R*)-4-(1-tert-Butyldiphenylsilanyloxybut-3-en-2-
yl)tetrahydropyran-2-one (26)
Water (30 cm3) and sodium periodate (2.40 g, 11.2 mmol) were
added to a stirred solution of 25 (1.10 g, 1.95 mmol) in methanol
(100 cm3). The resulting mixture was stirred at 25 ◦C for 20 min,
poured into dichloromethane, washed with brine (200 cm3) and
dried (MgSO4). The solvent was evaporated to give the selenoxide
(1.20 g) which was dissolved in benzene–triethylamine (1 : 1)
(2ꢀR*,4R*)-4-(1-tert-Butyldiphenylsilanyloxy-4-hydroxybutan-2-
yl)tetrahydropyran-2-one (24)
Ozone was bubbled through a solution of 17 (200 mg, 0.47 mmol)
in dichloromethane (10 cm3) at −78 ◦C until a faint blue
colour appeared. Nitrogen was bubbled through the solution for
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The Royal Society of Chemistry 2008
Org. Biomol. Chem., 2008, 6, 586–595 | 593
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