L.F. Tietze et al. / Journal of Organometallic Chemistry 687 (2003) 346ꢀ
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351
(C-7), 46.76 (C-7a), 72.79 (C(CH3)3), 81.57 (C-1), 110.3
(C-4), 125.1 (C-5), 128.0 (C-6), 144.9 (C-3a); MS (EI, 70
equivalents, 4.65 mmol, 186 mg) in THF (20 ml) was
refluxed for 22 h. H2O and Et2O were added to the
reaction mixture, the aqueous layer was separated and
extracted three times with Et2O, the combined organic
phases were washed with H2O, dried over Na2SO4 and
the solvent was removed in vacuo. After flash chroma-
eV): m/z (%)ꢂ
/
286, 284 (1) [M]ꢁ, 205 (14) [MꢃBr]ꢁ,
/
185, 183 (98) [Mꢃ
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C4H9ꢀ
/
C2H2ꢀ
/
H2O]ꢁ, 57 (100)
[C4H9]ꢁ; HRMS: Anal. Calc. for C14H21BrO:
284.0776, Found: 284.0776.
tography (100 g SiO2, pentane/MTBEꢂ
residue 15 was obtained in 72% yield (910 mg) as a
colourless oil. Rfꢂ0.52 (pentane/MTBEꢂ24:1); UV
(CH3CN): lmax (log o)ꢂ200 nm (4.627), 228 (4.047),
278 (3.730); IR (film): nꢂ
2971 cmꢃ1 (CH), 1592 (Cꢁ
C), 1466 (CꢁC), 1093 (CꢀOꢀ 58.38 (cꢂ1.0
C); [a]2D0ꢂ
in CHCl3); H-NMR (500 MHz, CDCl3): dꢂ0.94 (s,
3H, 7a-CH3), 1.16 (s, 9H, C(CH3)3), 1.61ꢀ1.70 (m, 1H,
2-Hb), 1.85ꢀ1.92 (m, 1H, 2-Ha), 2.06ꢀ2.24 (m, 3H, 3-
Hb, 7-H2), 2.41 (dd, Jꢂ18.8, 10.7 Hz, 1H, 3-Ha), 3.34
(d, Jꢂ16.2 Hz, 1H, 1ƒ-Hb), 3.39 (d, Jꢂ16.2 Hz, 1H, 1ƒ-
Ha), 3.67ꢀ3.76 (m, 4H, 1-H, OCH3), 5.57ꢀ5.61 (m, 2H,
6-H), 5.64 (dd, Jꢂ9.4, 3.0 Hz, 1H, 5-H), 6.60 (dd, Jꢂ
8.7, 3.1 Hz, 1H, 4?-H), 6.67 (d, Jꢂ3.1 Hz, 1H, 6?-H),
7.39 (d, Jꢂ
8.7 Hz, 1H, 3?-H); 13C-NMR (50.3 MHz,
CDCl3): dꢂ14.68 (7a-CH3), 23.79 (C-3), 28.78
/
49:1) of the
4.2.5. (ꢁ)-2-((1S,7aS)-1-tert-Butoxy-7a-methyl-
2,3,7,7a-tetrahydro-1H-inden-4-yl)-5,5-dimethyl-
/
/
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[1,3,2]dioxaborinane (16)
/
To a solution of 21 (1.0 equivalent, 4.91 mmol, 1.40 g)
and TMEDA (1.1 equivalents, 5.40 mmol, 810 ml) in
THF (50 ml) was added t-BuLi (2.05 equivalents, 10.1
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ꢁ
/
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1
/
mmol, 6.71 ml, 1.5 M in pentane) at ꢃ
/
78 8C and the
/
mixture was stirred at this temperature for 30 min. Then
B(Oi-Pr)3 (2.0 equivalents, 9.82 mmol, 2.28 ml) was
added, the reaction mixture was slowly warmed to r.t.
and stirred for 18 h. Brine and Et2O were added, the
aqueous layer was separated and extracted three times
with Et2O, the combined organic phases were dried over
Na2SO4 and the solvent was removed in vacuo. The
resulting residue was taken up in toluene (50 ml), 3,3-
dimethyl-propane-1,2-diol (1.2 equivalents, 5.09 mmol,
613 mg) was added and the mixture was stirred at r.t. for
22 h. H2O was added, the aqueous layer was separated
and extracted three times with CH2Cl2, the combined
organic phases were dried over Na2SO4 and the solvent
was removed in vacuo. Purification of the crude product
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(C(CH3)3), 30.23 (C-2), 36.09 (C-7), 37.16 (C-1ƒ),
43.30 (C-7a), 55.26 (OCH3), 72.53 (C(CH3)3), 81.70
(C-1), 113.0 (C-4?), 115.3 (C-6?), 115.6 (C-2?), 123.0 (C-
6), 124.0 (C-4), 126.8 (C-5), 132.9 (C-3?), 140.3, 143.2 (C-
3a, C-1?), 158.9 (C-5?); MS (DCI, 200 eV): m/z (%)ꢂ
830, 828, 826 (3) [2 Mꢁ
NH4]ꢁ, 441, 439 (26) [Mꢁ
NH4ꢁ
NH3]ꢁ, 424, 422 (100) [MꢁNH4]ꢁ; Anal. Calc.
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/
/
by flash chromatography (75 g SiO2, pentane/MTBEꢂ
19:1) gave 16 as a slightly yellow solid in 77% yield (12.1
g). Rfꢂ0.45ꢀ0.79 (pentane/MTBEꢂ9:1); m.p. 88 8C;
UV (CH3CN): lmax (log o)ꢂ282 nm (3.510); IR (KBr):
nꢂ C), 1097 (CꢀOꢀC);
2963 cmꢃ1 (CH), 1638 (Cꢁ
[a]2D0ꢂ 1.0 in CHCl3); 1H-NMR (300
71.58 (cꢂ
MHz, CDCl3): dꢂ0.89 (s, 3H, 7a-CH3), 0.97 (s, 6H,
C(CH3)2), 1.16 (s, 9H, C(CH3)3), 1.57ꢀ1.72 (m, 1H, 2-
Hb), 1.81ꢀ1.91 (m, 1H, 2-Ha), 2.04 (dbr, Jꢂ16.9 Hz,
1H, 7-Hb), 2.18 (dd, Jꢂ16.9, 6.2 Hz, 1H, 7-Ha), 2.34ꢀ
2.54 (m, 1H, 3-Hb), 2.73 (dd, Jꢂ20.4, 10.5 Hz, 1H, 3-
Ha), 3.63ꢀ3.69 (m, 5H, 1-H, 2ꢄ OCH2), 5.50ꢀ5.70 (m,
1H, 6-H), 6.13 (dd, Jꢂ
9.4, 3.0 Hz, 1H, 5-H); 13C-NMR
(75.5 MHz, CDCl3): dꢂ14.31 (7a-CH3), 21.92
/
/
/
for C22H29BrO2: C 65.18, H 7.21; Found: C 64.96, H
7.05%.
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4.2.7. (ꢁ)-(3S,3aS,5aS)-3-tert-Butoxy-8-methoxy-3a-
/
/
ꢁ
/
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methyl-1,2,3,3a,5a,10-hexahydro-cyclopenta[a]fluorene
(9)
/
/
A solution of 15 (1.0 equivalent, 123 mmol, 50 mg), 4
(0.05 equivalents, 6.2 mmol, 5.8 mg) and n-Bu4NOAc
(2.0 equivalents, 247 mmol, 74 mg) in a mixture of DMF/
MeCN/H2O (4 ml, 5:5:1) was heated at 140 8C for 5 min
applying microwave irradiation. The reaction mixture
was diluted with H2O and Et2O, the aqueous layer was
separated and extracted three times with Et2O, the
combined organic phases were dried over Na2SO4 and
the solvent was removed in vacuo. The crude product
was purified by flash chromatography (5 g SiO2,
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(C(CH3)2), 27.42 (C-3), 28.77 (C(CH3)3), 30.21 (C-2),
31.58 (C(CH3)2), 35.47 (C-7), 43.69 (C-7a), 71.90
(OCH2), 72.46 (C(CH3)3), 81.33 (C-1), 109.2 (C-4),
120.2 (C-5), 126.3 (C-6), 162.9 (C-3a); MS (EI, 70 eV):
pentane/MTBEꢂ
70% yield (28 mg). Rfꢂ
UV (CH3CN): lmax (log o)ꢂ
(3.816), 303 (3.499); IR (KBr): nꢂ
1609 (CꢁC), 1098 (CꢀOꢀ
C); [a]2D0ꢂ
CHCl3); H-NMR (600 MHz, CDCl3): dꢂ
3a-CH3), 1.15 (s, 9H, C(CH3)3), 1.74ꢀ1.81 (m, 1H, 2-
Hb), 1.87ꢀ1.93 (m, 1H, 2-Ha), 2.17ꢀ2.27 (m, 1H, 1-Ha),
2.36ꢀ2.44 (m, 1H, 1-Hb), 3.45 (s, 2H, 10-H2), 3.48 (dd,
Jꢂ9.8, 7.5 Hz, 1H, 3-H), 3.77 (s, 3H, OCH3), 4.06 (mc,
1H, 5a-H), 5.99 (dd, Jꢂ9.4, 3.2 Hz, 1H, 4-H), 6.10 (dd,
/
49:1) to give 9 as a colourless oil in
0.54 (pentane/MTBEꢂ24:1);
200 nm (4.453), 276
2973 cmꢃ1 (CH),
12.08 (cꢂ0.3 in
1.02 (s, 3H,
m/z (%)ꢂ
C4H8ꢀ
H2O]ꢁ, 57 (87) [C4H9]ꢁ; HRMS: Anal. Calc.
for C19H31BO3: 318.2366; Found: 318.2366.
/
318 (1) [M]ꢁ, 131 (100) [Mꢃ
/
C5H10BO2ꢀ
/
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ꢁ
/
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1
4.2.6. (ꢁ
/
)-(1S,7aS)-4-(2-Bromo-5-methoxy-benzyl)-
/
1-tert-butoxy-7a-methyl-2,3,7,7a-tetrahydro-1H-indene
/
(15)
/
/
A solution of 16 (1.2 equivalents, 3.10 mmol, 731 mg),
11 (1.0 equivalent, 3.72 mmol, 1185 mg), Pd(PPh3)4
(0.05 equivalents, 0.16 mmol, 179 mg) and NaOH (1.5
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/