P. A. Clarke et al. / Tetrahedron 61 (2005) 353–363
361
4.2.2. 1-Oxo-6-(tert-butyl dimethylsilanyloxy)-3-methyl-
3-(eth-2-enyl)-2-(carbo-tert-butoxy)-cycloheptane (22).
nmax (solution; CHCl3) 2955 (CH stretch), 2930 (CH
stretch), 1738 (C]O stretch), 1694 (C]O stretch), 1258
(C–O stretch), 1145 (C–O stretch), 1075 (Si–O stretch) and
835.3 (]CH oop bend) cmK1. dH (400 MHz; CDCl3) 5.87
(1H, dd, JZ17.5, 10.8 Hz, 3 vinyl), 5.04 (1H, dd, JZ17.5,
0.6 Hz, 3 vinyl), 5.02 (1H, dd, JZ10.8, 0.6 Hz, 3 vinyl),
4.16 (1H, m, H6), 3.95 (1H, s, H2), 2.75 (1H, ddd, JZ17.6,
5.9, 1.3 Hz, H7), 2.63 (1H, dd, JZ17.6, 3.2 Hz, H7), 2.11
(1H, ddd, JZ11.6, 3.2, 3.2 Hz, H5), 1.90 (1H, m, H5), 1.77
(1H, m, H4), 1.55 (1H, m, H4), 1.43 (9H, s, tBu), 1.24 (3H, s,
3Me), 0.92 (9H, s, TBS) and 0.08 (6H, t, JZ1.6 Hz, TBS)
ppm. dC (100 MHz; CDCl3) 206.3, 168.2, 146.2, 112.0,
80.9, 68.0, 66.0, 52.3, 40.1, 36.6, 32.2, 27.9, 25.7, 20.4,
18.0, 1.0, K4.9 and K5.1 ppm. MS (CI NH3) m/z 383 (MC
H)C; found MCH 383.2627, C21H39O4Si requires MCH
383.2618.
stretch), 1294 (C–O stretch), 1257 (C–O stretch), 1075 (Si–
O stretch) and 837 (]CH oop bend) cmK1. dH (400 MHz;
CDCl3) 4.33 (1H, m, H3), 4.15 (1H, dd, JZ14.0, 4.7 Hz,
H7), 4.04 (1H, dd, JZ13.1, 4.7 Hz, H9), 2.70 (1H, ddd, JZ
14.5, 14.0, 13.1 Hz, H8), 2.52–2.45 (2H, m, H2, H8), 2.25–
2.18 (2H, m, H4, H5), 2.04 (3H, s, Ac), 1.76–1.68 (2H, m,
t
H2, H4), 1.57 (1H, m, H5), 1.44 (9H, s, Bu), 1.38 (3H, s,
6Me), 0.90 (9H, s, TBS), 0.07 (3H, s, TBS) and 0.07 (3H, s,
TBS) ppm. dC (100 MHz; CDCl3) 168.8 (s, C10), 168.6 (s,
Ac), 101.8 (s, C1), 81.3 (s, tBu), 78.6 (s, C6), 65.1 (d, C3),
48.0 (d, C9), 39.9 (t, C2), 34.5 (t, C8), 33.0 (d, C7), 31.5 (t,
C5), 29.6 (t, C4), 28.0 (q, tBu), 28.0 (q, 6Me), 26.0 (q, TBS),
22.7 (q, Ac), 18.3 (s, TBS), K4.7 (q, TBS) and K4.8 (q,
TBS) ppm. MS (CI NH3) m/z 586 (MCNH4)C, 526 (MK
OAc, CNH4)C, 509 (MKOAc)C, 460 (MKI,CNH4)C,
327 (MKTBS, KI)C, 284 (MKTBS, KAc)C; found MC
NH4 586.2060, C23H45IO6SiN requires MCNH4 586.2061.
Anal. Calcd for C23H41IO6Si: C, 48.59, H, 7.27. Found C,
48.98, H, 7.17.
4.2.3. tert-Butyl-8-methyl-5-(tert-butyl dimethylsilanyl-
oxy)-3-oxo-dec-7,9-dienoate (23). nmax (solution; CHCl3)
2930 (CH stretch), 2884 (CH stretch), 1713 (C]O stretch),
1607 (C]O stretch), 1411 (CH bend), 1256 (C–O stretch),
1224 (C–O stretch), 1060 (Si–O stretch) and 830 (]CH oop
bend) cmK1. dH (400 MHz; DMSO) 6.34 (1H, dd, JZ10.7,
17.4 Hz, H9), 5.51 (1H, t, JZ7.0 Hz, H7), 5.10 (1H, d, JZ
17.4 Hz, H10 cis), 4.95 (1H, d, JZ10.7 Hz, H10 trans), 4.17
(1H, app pentet, JZ5.6 Hz, H5), 3.44 (2H, s, H2), 2.66 (1H,
dd, JZ16.2, 6.5 Hz, H4), 2.58 (1H, dd, JZ16.2, 4.0 Hz,
H4), 2.28 (2H, dd, JZ7.0, 6.5 Hz, H6), 1.68 (3H, s, 8Me),
1.40 (9H, s, tBu), 0.82 (9H, d, JZ1.6 Hz, TBS), 0.03 (3H, d,
JZ1.3 Hz, TBS) and 0.00 (3H, d, JZ1.3 Hz, TBS) ppm. dC
(100 MHz; DMSO) 202.1 (s, C3), 166.1 (s, C1), 141.2 (s,
C8), 135.4 (d, C7), 128.4 (d, C9), 111.4 (t, C10), 80.7 (s,
tBu), 68.1 (d, C5), 51.2 (t, C2), 49.4 (t, C4), 35.8 (t, C6),
4.2.6. 9-(Carbo-tert-butoxy)-7-iodo-6-methyl-3-(tert-
butyl dimethylsilanyloxy)-oxabicyclo[4.3.1]non-9-ene
(29). Mp 89–90 8C. nmax (solution; CHCl3) 2955 (CH
stretch), 2857 (CH stretch), 1698 (C]O stretch), 1432 (CH
bend), 1258 (C–O stretch), 1146 (C–O stretch), 1059 (Si–O
stretch) and 836 (]CH oop bend) cmK1. dH (400 MHz;
CDCl3) 4.41 (1H, t, JZ8.4 Hz, H7), 4.21 (1H, m, H3), 3.58
(1H, dt, JZ12.5, 1.8 Hz, H2), 3.17 (1H, dd, JZ18.8,
7.6 Hz, H8), 3.04 (1H, ddd, JZ18.8, 8.4, 1.8 Hz, H8), 2.30
(1H, dd, JZ14.6, 11.0 Hz, H5), 2.23 (1H, ddd, JZ12.5, 4.7,
1.8 Hz, H2), 1.78 (1H, ddt, JZ13.0, 12.4, 1.5 Hz, H4), 1.72
(1H, m, H4), 1.49 (1H, m, H5), 1.46 (9H, s, tBu), 1.44 (3H, s,
6Me), 0.88 (9H, s, TBS) and 0.57 (6H, s, TBS) ppm. dC
(100 MHz; CDCl3) 166.6 (s, C10), 161.9 (s, C9), 128.4 (s,
t
C1), 116.9 (s, C6), 80.2 (s, Bu), 78.1 (d, C3), 67.4 (t, C2),
t
27.7 (q, Bu), 25.7 (q, TBS), 17.6 (s, TBS), 11.7 (q, 8Me),
42.4 (t, C8), 36.0 (d, C7), 33.6 (t, C4), 31.9 (t, C5), 28.5 (q,
tBu), 26.2 (q, TBS),26.1 (q, 6Me), 18.4 (s, TBS), K4.7 (q,
TBS) and K5.0 (q, TBS) ppm. MS (ESC) m/z 509 (MC
H)C, 453 (MCH, KtBu)C, 395 (MCH, KTBS)C; found
MCH 509.1580, C21H38IO4Si requires MCH 509.1579.
Anal. Calcd for C21H37IO4Si: C, 49.60, H, 7.33. Found C,
49.25, H, 7.21.
K4.8 (q, TBS) and K5.0 (q, TBS) ppm. MS (ESC) m/z 383
(MCH)C, 327 (MCH, KtBu)C and 309 (MCH,
KTBS)C; found MCH 383.2620, C21H39O4Si requires
MCH 383.2618.
4.2.4. Iodocyclization of 17. Synthesis of 24 and 29. To a
mixture of iodine (1.92 g, 7.6 mmol) and silver acetate
(1.26 g, 7.6 mmol) was added acetic acid (54 ml). The
mixture was stirred for 30 min before being transferred via
syringe to a solution of 17 (1.00 g, 2.5 mmol) in acetic acid
(21 ml). The mixture was stirred for 1 h before being diluted
with water (500 ml) and CH2Cl2 (100 ml), and neutralized
with solid NaHCO3. The resulting solution was saturated
with solid sodium chloride and extracted with CH2Cl2 (5!
200 ml). The organic phase was washed with saturated
aqueous sodium thiosulfate solution (500 ml), saturated
aqueous NaHCO3 solution (3!200 ml), water (3!200 ml)
and brine (250 ml) before being dried (MgSO4) and
concentrated in vacuo. The resulting oil was subjected to
column chromatography (98:2 petrol–ether) to give 24
(816 mg, 4.6 mmol, 61%) as a colorless oil, 29 (73 mg,
0.13 mmol, 5%) as a white crystalline solid.
4.2.7. 7-Hydroxy-5-methyl-4-iodo-10,6-dioxatricyclo-
[5.3.2.0]dodecan-1-one (28). To a solution of 27 (37 mg,
0.087 mmol) in CH2Cl2 (2 ml) was added TFA (0.01 ml,
0.1 mmol) and the mixture stirred for 4 days. Further
portions (0.01 ml, 0.1 mmol) of TFA were added after 1, 2
and 3 days. The mixture was concentrated in vacuo to give
the product (29 mg, 0.087 mmol, 100%) as a colorless oil.
nmax (solution; CHCl3) 3573 (br, OH stretch), 3186 (CH
stretch), 2932 (CH stretch), 1780 (C]O stretch), 1453 (CH
bend), 1152 (C–O stretch) and 1118 (C–O stretch) cmK1. dH
(400 MHz; CDCl3) 5.52 (1H, dddd, JZ12.3, 6.5, 6.5,
3.3 Hz, H9), 4.06 (1H, m, H4), 2.74–2.62 (4H, m, H8, H8,
H3, H3), 2.46 (1H, m, H11), 2.29 (1H, m, H12), 2.09 (1H,
dd, JZ14.3, 3.1 Hz, H2), 1.85 (1H, ddd, JZ15.2, 4.2,
2.8 Hz, H12), 1.68 (1H, ddd, JZ15.2, 7.1, 3.3 Hz, H11)
1.44 (1H, s, OH) and 1.42 (3H, s, 5Me) ppm. dC (100 MHz;
CDCl3) 172.7 (s, C1), 95.9 (s, C5), 78.1 (s, C7), 72.8 (d, C9),
54.7 (d, C4), 35.7 (t, C3 or C8), 34.5 (t, C3 or C8), 31.3 (d,
C2), 29.2 (t, C12), 28.0 (q, 5Me) and 27.4 (t, C11) ppm. MS
4.2.5. 9-(Carbo-tert-butoxy)-7-iodo-6-methyl-3-(tert-
butyl dimethylsilanyloxy)-1-acetoxy-oxabicyclo[4.3.1]-
nonane (24). nmax (solution; CHCl3) 2990 (CH stretch),
2857 (CH stretch), 1747 (C]O stretch), 1721 (C]O