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M. E. Krafft et al. / Tetrahedron 62 (2006) 11782–11792
3.1.13. Vinyl sulfone (45). Butyllithium (32.3 mL, 1.42 M,
45.8 mmol) was added dropwise to methylphenylsulfone
(3.60 g, 22.9 mmol) in THF (150 mL) at 0 ꢁC and the solu-
tion was stirred for 30 min. Diethylchlorophosphate
(3.6 mL, 22.9 mmol) in THF (30 mL) was added dropwise
and the mixture was stirred for 30 min. After cooling to
ꢀ78 ꢁC, aldehyde 44 (6.34 g, 20.8 mmol) in THF (30 mL)
was added and the mixture was stirred for 3 h. Upon warm-
ing to rt the mixture was stirred for an additional 2 h. Brine
(200 mL) was added and the mixture extracted with EtOAc.
The combined organic extracts were dried over MgSO4, fil-
tered, and evaporated, and the resultant oil passed through
a plug of silica gel (hexane/EtOAc, 1:1). After evaporation
of the solvent the resultant oil was further purified by flash
column chromatography (hexane/EtOAc, 95:5) to give
vinylsulfone 45 as a 2.5:1 mixture of E/Z isomers (6.76 g,
73%) as a colorless oil: IR 3063, 2953, 1748, 1634,
1585 cmꢀ1; MS (ESI+) m/z 465 (M+Na); Anal. Calcd for
C21H34O6SSi: C, 56.98; H, 7.74. Found: C, 57.07; H, 7.80.
PhSO2CHCH), 6.47 (1H, d, J¼15.1 Hz, PhSO2CH), 4.22–
4.11 (4H, m, CH3CH2), 3.55 (2H, t, J¼5.9 Hz, TBSOCH2),
3.09 (1H, ddd, J¼10.3, 10.3, 2.4 Hz, PhSO2CHCHCH), 2.84
(1H, dd, J¼17.1, 2.4 Hz, HCCCHH), 2.70 (1H, dd, J¼17.1,
2.4 Hz, HCCCHH), 1.98 (1H, t, J¼2.4 Hz, CH2CCH), 1.87–
1.81 (1H, m, TBSOCH2CH2CHH), 1.49–1.40 (1H, m,
TBSOCH2CHH), 1.4–1.3 (2H, m, TBSOCH2CHHCHH),
1.24 (3H, t, J¼7.3 Hz, CH2CH3), 1.22 (3H, t, J¼7.3 Hz,
CH2CH3), 0.87 (9H, s, C(CH3)3), 0.01 (6H, s,
(H3C)3CSi(CH3)2); 13C NMR d 168.6, 168.5, 145.0, 140.6,
133.6, 133.3, 129.2, 127.5, 78.4, 72.2, 62.4, 61.9, 59.7,
44.3, 30.9, 25.9, 23.6, 18.2, 13.9, ꢀ5.4; HRESIMS calcd
for C28H42O7SiSNa ([M+Na]+): 573.2318; found: 573.2320.
3.1.16. Bicyclooctenone (49). Dicobaltoctacarbonyl
(1.31 g, 3.83 mmol) was added to enyne 47 (2.01 g,
3.65 mmol) in hexane (18 mL). After the enyne was con-
sumed according to TLC the solvent was evaporated and
CH2Cl2 (73 mL) was added. Anhydrous trimethylamine
N-oxide (250 mg, 3.65 mmol) was added every 30 min
four times under an oxygen atmosphere and the mixture
was stirred until the alkyne cobalt complex was consumed
according to TLC. The mixture was passed through a plug
of silica gel (EtOAc). After evaporation of solvent the resul-
tant oil was further purified by flash column chromato-
graphy (hexane/EtOAc, 4:1) to give bicyclooctenone 49
(1.73 g, 82%) as a white solid: mp 109–111 ꢁC; IR 3066,
3.1.14. Malonate (46). A solution of diethyl malonate
(1.6 mL, 10.6 mmol) and allylcarbonate 45 (1.18 g,
2.66 mmol) in degassed THF (26 mL) was added to a
suspension of tris(dibenzylideneacetone)dipalladium(0)-
chloroform (140 mg, 0.13 mmol), 1,2-bis(diphenylphos-
˚
phino)ethane (210 mg, 0.53 mmol), and 4 A powdered
molecular sieves (0.6 g, half by weight of allylcarbonate
(45) in degassed THF (10 mL). After heating to reflux for
12 h the mixture was cooled to rt, passed through Celite
and the solvent was evaporated. The resultant oil was puri-
fied by flash column chromatography (hexane/EtOAc,
95:5) to give malonate 46 (1.1 g, 81%) as a white solid,
1
2929, 1713, 1644, 1586 cmꢀ1; H NMR d 7.94–7.92 (2H,
m, ArH), 7.67 (1H, t, J¼7.3 Hz, ArH), 7.57 (2 H, br t, J¼
7.3 Hz, ArH), 5.86 (1H, d, J¼1.0 Hz, (EtO2C)2CCH2CCH),
4.32 (1H, ABq, JAB¼10.5, J¼7.3 Hz, CH3CHH), 4.26 (1H,
ABq, JAB¼10.5, J¼7.3 Hz, CH3CHH), 4.22 (1H, ABq,
1
mp 62–64 ꢁC: IR 3059, 2931, 2857, 1733, 1625 cmꢀ1; H
JAB¼10.5, J¼7.3 Hz, CH3CHH), 4.19 (1H, ABq, JAB¼
NMR d 7.87–7.85 (2H, m ArH), 7.60 (1H, tt, J¼7.3,
1.0 Hz, ArH), 7.52 (2H, t, J¼7.3 Hz, ArH), 6.88 (1H, dd,
J¼15.1, 9.3 Hz, PhO2SCHCH), 6.39 (1H, d, J¼15.1 Hz,
PhO2SCHCH), 4.12 (2H, q, J¼6.8 Hz, CH3CH2), 4.06 (1H,
ABq, JAB¼10.0, J¼6.8 Hz, CH3CHH), 4.03 (1H, ABq,
JAB¼10.0, J¼6.8 Hz, CH3CHH), 3.55 (2H, t, J¼5.9 Hz,
TBSOCH2), 3.43 (1H, d, J¼8.3 Hz, (EtO2C)2CH), 2.99
(1H, ddt, J¼9.3, 8.3, 5.0 Hz, (EtO2C)2CHCH), 1.65
(1H, m, TBSOCH2CH2CHH), 1.55–1.37 (3H, m,
TBSOCH2CH2CHH), 1.21 (3H, t, J¼6.8 Hz, CH2CH3),
1.18 (3H, t, J¼6.8 Hz, CH2CH3), 0.86 (9H, s, C(CH3)3),
0.01 (6H, s, (H3C)3CSi(CH3)2); 13C NMR d 167.3, 167.1,
145.7, 140.3, 133.3, 132.7, 129.1, 127.5, 62.3, 61.6, 61.5,
55.7, 41.2, 30.0, 28.3, 25.8, 18.2, 13.9, ꢀ5.5; Anal. Calcd
for C25H40O7SSi: C, 58.56; H, 7.86. Found: C, 58.87;
H, 7.87.
10.5, J¼7.3 Hz, CH3CHH), 3.97 (1H, d, J¼2.9 Hz, PhO2-
SCH), 3.73–3.61 (3H, m, TBSOCH2 and PhSO2CHCH),
3.60 (1H, partly obscured d, J¼18.4 Hz, (EtO2C)2CCHH),
3.03 (1H, d, J¼18.4 Hz, (EtO2C)2CCHH), 2.40 (1H, ddd,
J¼12.2, 7.3, 6.3 Hz, TBSO(CH2)3CH), 1.88–1.68 (4H, m,
TBSOCH2CH2CH2), 1.32 (3H, t, J¼7.3 Hz, CH2CH3), 1.27
(3H, t, J¼7.3 Hz, CH2CH3), 0.88 (9H, s, C(CH3)3), 0.05
(3H, s, (H3C)3CSi(CH3)2), 0.04 (3H, s, (H3C)3CSi(CH3)2);
13C NMR d 196.8, 183.3, 170.5, 138.1, 134.1, 129.3,
128.9, 124.9, 72.5, 63.2, 63.0, 62.1, 61.8, 50.8, 49.1, 36.6,
31.1, 27.3, 25.9, 18.2, 14.0, 13.9, ꢀ5.4; Anal. Calcd for
C29H42O8SSi: C, 60.18; H, 7.31. Found: C, 59.93; H, 7.40.
3.1.17. Aldehyde (50). Decaborane (15 mg, 0.12 mmol) was
added to a solution of enone 49 (1.34 g, 2.32 mmol) in meth-
anol (18 mL) and THF (5 mL). After stirring at rt for 2 h the
solvent was evaporated. The resultant oily residue was puri-
fied by flash column chromatography (hexane/EtOAc, 3.2)
to give alcohol (1.01 g, 94%) as a colorless oil: IR 3548,
3.1.15. Enyne (47). Malonate 46 (0.81 g, 1.57 mmol) was
added to an ice cold suspension of hexane washed 60%
sodium hydride (69 mg, 1.73 mmol) in THF (16 mL) and
the mixture was stirred for 3 h. Propargyl bromide
(3.5 mL, 31.4 mmol) was added and the mixture was stirred
overnight. Water (30 mL) was added and the mixture was ex-
tracted with EtOAc. The combined organic extracts were
dried over MgSO4, filtered, and evaporated and the resultant
oil purified by flash column chromatography (hexane/
EtOAc, 9:1) to give enyne 47 (0.86 g, 99%) as a colorless
2937, 1720, 1639 cmꢀ1
;
1H NMR d 7.93 (2H, d,
J¼7.3 Hz, ArH), 7.68 (1H, t, J¼7.3 Hz, ArH), 7.58 (2H, t,
J¼7.3 Hz, ArH), 5.87 (1H, s, (EtO2C)2CCH2CCH), 4.33
(1H, ABq, JAB¼10.8, J¼6.9 Hz, CH3CHH), 4.28 (1H, ABq,
JAB¼11.2, J¼7.3 Hz, CH3CHH), 4.27 (1H, ABq, JAB¼11.2,
J¼7.3 Hz, CH3CHH), 4.18 (1H, ABq, JAB¼10.8, J¼7.3 Hz,
CH3CHH), 3.92 (1H, d, J¼3.4 Hz, PhO2SCH), 3.73–3.64
(3H, m, HOCH2 and PhSO2CHCH), 3.59 (1H, d,
J¼18.6 Hz, (EtO2C)2CCHH), 3.01 (1H, d, J¼18.6 Hz,
(EtO2C)2CCHH), 2.40 (1H, ddd, J¼12.2, 7.3, 4.9 Hz,
HO(CH2)3CH), 1.92–1.73 (4H, m, HOCH2CH2CH2), 1.33
1
oil: IR 3276, 2930, 2857, 1732 cmꢀ1; H NMR d 7.89–
7.87 (2H, m, ArH), 7.60 (1H, tt, J¼7.8, 1.5 Hz, ArH), 7.53
(2H, br t, J¼7.8 Hz, ArH), 6.87 (1H, dd, J¼15.1, 10.3 Hz,