H.-J. Gutke et al. / Tetrahedron 57 (2001) 997±1003
1001
the pyridine was removed under reduced pressure, the
remaining semisolid dissolved in Et2O/H2O (1:1, 100 ml),
the organic phase separated and the aqueous extracted with
Et2O (3£50 ml). The combined organic phase was washed
(2 N HCl sat. aqueous NaHCO3), dried (MgSO4), concen-
trated and the remaining residue chromatographed (silica
stirred at room temp. to form the corresponding ylid.
After 20 min a solution of (anti/syn)-8a (1.09 g, 2.5
mmol) in THF (2 ml) was added and stirring continued at
room temp. overnight. H2O (3 ml) was added, the organic
phase was separated, the aqueous phase extracted with
CH2Cl2 (3£20 ml) and the combined organic phases dried
(MgSO4), concentrated and the residue chromatographed on
silica gel (petroleum ether/Et2O: 211). Yield: 0.82 g (71%),
oil. IR (®lm): n~3090 cm21, 3070, 3030, 2970, 2940, 2880
(CH), 1705 (CyO), 1500, 1455, 1380, 1370, 1290, 1270,
1
gel, Et2O). Yield: 0.53 g (65%), oil. H NMR (CDCl3): IR
(®lm): n~3060 cm21, 2980, 2930 (CH), 1740, 1715 (CyO),
1600, 1495, 1470, 1450, 1410, 1365 (ROZSO2ZR0), 1300,
1
1275, 1240, 1195, 1185 (ROZSO2ZR0), 1160, 1105. H
1
NMR (CDCl3) d1.27 (t, J7.2 Hz, 3H, OCH2CH3), 1.67
(m, 1H, CH2CH2O), 1.94±2.07 (m, 2H, 3-H and 4-H), 2.40±
2.52 (m, 3H, 3-H, 4-H and 7-H), 2.46 (s, 3H, CH3), 2.54 (m,
1H, CH2CH2O), 2.65 (m, 1H, 5-H), 2.73±2.82 (m, 2H, 7-H
and 8-H), 4.11 (t, J6.0 Hz, 2H, CH2CH2O), 4.18±4.26 (m,
2H, OCH2CH3), 7.37 (dd, J0.7 Hz, 8.6 Hz, 2H, C6H4Me),
7.78 (dd, J0.3 Hz, 8.6 Hz, 2H, C6H4Me). 13C NMR
(CDCl3): d14.02 (q, OCH2CH3), 21.61 (q, CH3), 21.81
(t, CH2CH2O), 24.97 (t, C-4), 34.57 (t, C-3), 44.05 (d, C-
8), 46.40 (t, C-7), 48.29 (d, C-5), 61.55 (t, CH2CH2O), 63.62
(s, C-1), 68.79 (t, OCH2CH3), 127.83 and 129.95 (d,
C6H4Me), 132.71 and 145.11 (s, C6H4Me), 169.56 (s,
ester-C), 204.70 (s, C-2), 212.45 (s, C-6). APCI-MS;
m/z (%): 409 (62) [M11H], 363 (4) [M11H2
C2H6O], 237 (100), 209 (18), 155 (4) [C7H7O2S1].
C20H24O7S (408.47): calcd C 58.81%, H 5.92%; found
C 58.67%, H 5.99.
1245, 1205, 750 (C6H5), 710 (C6H5). H NMR (CDCl3):
d1.19 (t, J7.1 Hz, 3H, OCH2CH3), 1.34 (m, 1H, 8-H),
1.61 [s, 3H, C(CH3)2], 1.69±1.86 (m, 2H, 4-H and
CH2CH2OBzl), 1.74 [s, 3H, C(CH3)2], 2.14 (m, J3.2 Hz,
1H, 3-H), 2.26±2.44 (m, 1H, 4-H and 5-H), 2.55±2.65 (m,
2H, 3-H and CH2CH2OBzl), 2.93 (s, 1H, C-7), 3.50±3.58
(m, 2H, CH2CH2OBzl), 4.05±4.19 (m, J7.1 Hz, 2H,
OCH2CH3), 4.40 (d, J11.1 Hz, 1H, C2H4OCH2Ph), 4.50
(d, J12.0 Hz, 1H, OCH2C6H5), 4.56 (d, J11.1 Hz, 1H,
C2H4OCH2Ph), 4.57 (d, J12.0 Hz, 1H, OCH2C6H5), 7.23±
7.35 (m, 5H, C6H5). 13C NMR (CDCl3): d14.12 (q,
OCH2CH3), 20.20 and 20.42 [q, C(CH3)2], 21.06 (t, C-4),
21.64 (t, C-3), 28.19 (t, CH2CH2OPh), 36.27 (d, C-8), 38.46
(d, C-5), 40.31 (d, C-7), 41.86 (s, C-1), 60.36 (t, OCH2CH3),
69.63 (t, CH2CH2OBzl), 69.73 (t, OCH2Ph), 71.16 (s, C-2),
72.67 (t, C2H4OCH2Ph), 119.39 (s, C-6), 127.41,
127.48, 127.56, 127.64, 128.18 and 128.27 (d, C6H5),
134.44 [s, C(CH3)2], 138.07 and 138.58 (s, C6H5),
170.99 (s, ester-C). ESI-MS; m/z (%): 499 (16) [M11
K], 483 (100) [M11Na], 461 (52) [M11H], 415 (4).
C30H36O4 (460.61): calcd C 78.23%, H 7.88%; found C
78.12%, H 7.93%.
3.1.9. Ethyl 2,5-dioxotricyclo[4.3.1.03,7]decane-3-carb-
oxylate (12). To a freshly prepared and stirred solution of
LDA (3.45 mmol) in THF (15 ml) at 2788C was added a
solution of tosylate 11 (0.47 g, 1.15 mmol) in THF (3 ml)
with a syringe. Stirring was continued at this temperature for
30 min and at room temp. for 5 h. H2O was added (10 ml),
the organic phase separated, the aqueous extracted with
Et2O (4£20 ml), the combined organic phases washed
with brine (5 ml) and dried (MgSO4). The solvent was
distilled off and the remaining oil puri®ed chromato-
graphically (silica gel, Et2O/petroleum ether: 111). Yield:
3.1.11. Methyl 8-(2-benzyloxy-ethyl)-6-isopropyl-2-oxo-
bicyclo[3.2.1]oct-6-ene-1-carboxylate (14). To a solution
of (anti/syn)-8b (1.67 g, 4.85 mmol) in anhydrous toluene
(70 ml) was added a mixture of KOtBu (505 mg, 5 mmol)
and isopropyltriphenylphosphonium bromide (1.93 g,
5 mmol). The mixture was heated under re¯ux for 1 h. A
second portion of the mixture was added, this was repeated
after 1 h and the mixture was re¯uxed for an additional hour.
The reaction mixture was cooled to room temp. and diluted
with petroleum ether (100 ml) to precipitate triphenyl-
phospine oxide. The organic phase was ®ltered through a
pad of silica gel (solvent: petroleum ether/Et2O, 111). The
solvent was distilled off, the residue was dissolved in
CH2Cl2 (100 ml) and acidi®ed with ®ve drops of conc.
HCl. After stirring for 12 h the solvent was evaporated
and the residue chromatographed on silica gel (petroleum
ether/Et2O: 311, Rf0.23) to yield 518 mg (30%) of a
colorless oil. IR (®lm): n~3061 cm21, 2953, 2867 (CH),
79 mg (29%), viscous liquid. IR (®lm): n~2960 cm21
,
2930, 2880 (CH), 1735, 1715 (CyO), 1470, 1450, 1410,
1
1370, 1305, 1280, 1240, 1175, 1105, 1050, 1005, 875. H
NMR (CDCl3): d1.30 (t, J7.2 Hz, 3H, CH2CH3), 1.66±
1.74 (m, 2H, 8-H), 1.87±2.01 (m, 2H, 9-H and 10-H), 2.04±
2.15 (m, 2H, 9-H and 10-H), 2.50 (m, 1H, 7-H), 2.52 (d,
J18.9 Hz, 1H, 4-H), 2.65 (m, 1H, 6-H), 2.72 (m, 1H, 1-H),
2.96 (dd, J1.9 Hz, J18.9 Hz, 1H, 4-H), 4.18±4.31 (m,
J7.2 Hz, 2H, CH2CH3). 13C NMR (CDCl3): d14.09 (q,
CH2CH3) 16.28 (t, C-8), 24.07 (t, C-9), 25.27 (t, C-10),
41.19 (d, C-7), 41.81 (d, C-1), 44.83 (t, C-4), 47.54 (d,
C-6), 61.87 (t, CH2CH3), 62.41 (s, C-3), 169.39 (s, ester-
C), 211.30 (s, C-2), 214.78 (s, C-5). GC±MS; m/z (%): 236
(40) [M1], 208 (12) [M12C2H5], 191 (15) [M12C2H5O],
190 (32) [M12C2H6O], 180 (2), 162 (36), 151 (9), 134 (31),
117 (15), 107 (52), 91 (47), 80 (53), 79 (100), 67 (42), 55
(61). HRMS: C13H16O4: calcd 236.1049 [M1]; found
236.1066.
1
1740 (CyO), 1694 (CyC), 1550, 1366, 1251, 1120. H
NMR (CDCl3): d1.15 (d, J7.0 Hz, 3H, CH3), 1.75 (d,
J7.0 Hz, 3H, CH3), 1.5±1.85 (m, 3H, CH2CH2O, 4-H),
2.08 (m, 1H, 4-H), 2.28 (dd, J17.0 Hz, 7.6 Hz, 1H, 3-H),
2.4 (m, 1H, CH2CH2O), 2.48 [hept, J7.0 Hz, 1H,
CH(CH3)2], 2.70 (m, 1H, 3-H), 2.78 (m, 1H, 8-H), 3.93
(m, 1H, 5-H), 3.61 (t, J6.4 Hz, 2H, OCH2), 3.80 (s, 3H,
OCH3), 4.53 and 4.60 (d, J12.2 Hz, each 1H, CH2Ph), 5.80
[s (br),1H, 7-H], 7.25±7.32 (m, 5H, Aryl-H). 13C NMR
(CDCl3): d20.72 and 20.83 (q, CH3), 21.22 (t, C-4),
26.39 (t, CH2CH2O), 29.14 [d, CH(CH3)2], 34.52 (t, C-3),
42.25 (d, C-8), 51.93 (q, OCH3), 52.24 (d, C-5), 68.63
3.1.10. Ethyl 2-benzyloxy-8-(2-benzyloxy-ethyl)-6-iso-
propylidene-tricyclo[3.2.1.02,7]octane-1-carboxylate (13a).
To a ready-to-use mixture of isopropyltriphenylphos-
phonium bromide/sodium amide (1.09 g, 2.3 mmol) was
added THF (6 ml) with a syringe. The suspension was