R. Kawe˛cki / Tetrahedron: Asymmetry 14 (2003) 2827–2832
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the presence of catalytic amount of FeCl3·6H2O, was
added at −65°C a solution of sultine 6 (2.05 g, 10.1
mmol) in THF (30 mL). The reaction mixture was
stirred at −65°C for 30 min and carefully quenched with
solid NH4Cl (5.3 g). The ammonia was evaporated and
THF was removed under vacuum. The residue was
dissolved in 15 mL of H2O and 25 mL of CH2Cl2.
Organic layer was separated and aqueous solution was
extracted three times with CH2Cl2. Combined organic
extracts were dried and evaporated to give colorless
solid (2.14 g, 96%) pure enough for next step. Analyti-
cal sample was prepared by recrystallization from hex-
ane–CH2Cl2. Yield 82%. Mp 108–114°C; [h]D=+5.0 (c
1.41, CH2Cl2); IR (KBr) 3367, 3208 (NH), 1024 (SꢀO);
1H NMR (CDCl3) l 0.75–1.15 (m, 2H), 0.89 (d, J=6.6
Hz, 3H), 1.22 (s, 3H), 1.24 (s, 3H), 1.3–1.55 (m, 2H),
1.6–2.05 (4H), 3.1 (br, 1H), 3.48 (ddd, J=3.8, 10.3 Hz,
1H), 4.3 (br, 2H); 13C NMR (CDCl3) l 17.4, 20.0, 21.8,
26.2, 31.3, 34.3, 45.6, 47.1, 62.5, 71.1. Anal calcd for
C10H21NO2S: C, 54.76; H, 9.65; N, 6.39; S, 14.62.
Found: C, 54.89; H, 9.75; N, 6.59; S, 14.57.
7.78–7.90 (m, 2H), 8.54 (s, 1H); 13C NMR (CDCl3) l
1.0, 16.5, 17.4, 21.9, 26.1, 31.2, 34.4, 45.4, 49.0, 64.9,
73.0, 128.7, 129.3, 132.0, 134.3, 162.3. HR LSIMS calcd
for C20H34O2NSiS 380.2080 (M+H). Found 380.2087.
4.1.7. General procedure for the addition of ethylmagne-
sium bromide to sulfinimines. To a cooled (−30°C) solu-
tion of sulfinimine (0.33 mmol) in CH2Cl2 or THF (2.5
mL) was added an ether solution of ethylmagnesium
bromide (0.57 mL, 1 mmol). The mixture was stirred
for 3.5 h at −30°C and then quenched with saturated
aqueous solution of NH4Cl (3 mL). The organic layer
was separated and the water phase was extracted with
CH2Cl2. Combined extracts were dried (MgSO4) and
evaporated.
4.1.7.1. (1S,1%R,2R,4R,SS)-7,7-Dimethyl-N-(1%-phenyl-
propyl)-2-trimethylsilyloxybicyclo[2.2.1]heptane-1-
methanesulfinamide, 11b. The product was purified by
chromatography on silicagel (CH2Cl2 and MeOH
100:1). Colorless solid, yield 85%. Major diastereoiso-
1
mer: IR (neat) 3430 (NH), 1088, 1047, 1021 (SꢀO); H
NMR (CDCl3) l −0.11 (s, 9H), 0.7–1.1 (m, 2H), 0.78 (s,
3H), 0.80 (t, J=7.3 Hz, 3H), 0.96 (s, 3H), 1.16–1.38 (m,
1H), 1.50–1.89 (m, 6H), 2.47 and 3.18 (AB, J=12.6 Hz,
2H), 3.81 (dd, J=7.2, 3.4 Hz, 1H), 4.0 (d, J=2.4 Hz,
1H), 4.23 (ddd, J=2.6, 6.4, 8.5 Hz, 1H), 7.18–7.33 (m,
5H); 13C NMR (CDCl3) l 0.1, 10.5, 20.0, 20.4, 27.2,
30.0, 31.2, 41.7, 44.5, 48.6, 50.0, 56.0, 59.8, 76.7, 127.4,
127.7, 128.3, 141.1. HR LSIMS calcd for
C22H38NO2SSi 408.23925 (M+H). Found 408.24085.
4.1.5. (1R,2R,4R,SS)-2-(2-Trimethylsilyloxy-4-methylcy-
clohexyl)propane-2-sulfinamide, 9c. To the solution of
sulfinamide 8c (2.14 g, 9.8 mmol) in pyridine (30 mL)
and HMDS (16.1 mL, 78.1 mmol) was added TMSCl
(4.95 mL, 39 mmol) at rt. The mixture was stirred for
16 h and saturated solution of NaHCO3 was added
(cooling with cold water bath). The mixture was diluted
with water (20 mL) and extracted with CH2Cl2. Com-
bined extracts were dried with MgSO4 and the solvents
were removed by evaporation under vacuum (50°C).
The product was purified by chromatography on short
column (silicagel, elution with ethyl acetate and hexane
4:3, then 2:1). Yield 1.88 g (66%). Colorless crystals,
Mp 64–68°C; [h]D −13.2 (c 1.78, CH2Cl2); IR (film)
4.1.7.2. (1R,1%R,2R,4R,SS)-N-(1%-phenylpropyl)-2-(2-
trimethylsilyloxy-4-methylcyclohexyl)propane-2-sulfi-
namide, 11c. Major diastereoisomer: colorless oil, IR
(neat) 3223 (NH), 1067, 1047 (SꢀO) cm−1;1H NMR
(CDCl3) l −0.04 (s, 9H), 0.65–1.08 (m, 3H), 0.84 (t,
J=7.6 Hz, 3H), 0.86 (d, J=7.3 Hz, 3H), 1.12 (s, 3H),
1.20 (s, 3H), 1.25–1.46 (m, 1H), 1.52–1.92 (m, 6H), 3.19
(bd, J=3.8 Hz, 1H), 3.51 (ddd, J=10.4, 10.4, 4.0 Hz,
1H), 4.22 (m, 1H), 7.2–7.33 (m, 5H); 13C NMR
(CDCl3) l 0.7, 10.6, 16.4, 17.3, 21.9, 26.0, 31.1, 31.7,
34.4, 45.4, 48.3, 60.7, 62.3, 73.0, 127.1, 127.7, 128.2,
142.2. HR LSIMS calcd for C22H40NO2SSi 410.25490
(M+H). Found 410.25618.
1
3227 (NH), 1066, 1045 (SꢀO); H NMR (CDCl3) l 0.12
(s, 9H), 0.72–1.08 (m, 3H), 0.86 (d, J=6.6 Hz, 3H),
1.12 (s, 3H), 1.19 (s, 3H), 1.26–1.49 (m, 1H), 1.56 (m,
4H), 3.49 (br, 2H), 3.60 (ddd, J=4.2, 9.8, 10.4 Hz, 1H);
13C NMR (CDCl3) l 0.8, 15.1, 16.6, 21.8, 26.1, 31.0,
34.1, 45.3, 48.7, 62.1, 72.7. HR LSIMS calcd for
C13H29O2NNaSiS 314.1586 (M+Na). Found 314.1583.
4.1.6.
(1R,2R,4R,SS)-N-[(1E)-Benzylidene]-2-(2-
4.1.8. Recovery of the sultine 6. To the solution of
sulfinamide 11c (0.25 mmol) in diethyl ether (2 mL) was
added HCl·Et2O (1.5 mL, ca. 1 M). After 30 min the
precipitated hydrochloride 12 was filtered and washed
with hexane. The filtrate was evaporated to give sultine
6 which may be purified by crystallization from cyclo-
hexane. Free amine was obtained from hydrochloride
12 by standard workup.
trimethylsilyloxy-4-methylcyclohexyl)propane-2-sulfi-
namide, 10c. To the solution of sulfinamide 9c (970 mg,
3.3 mmol) and benzaldehyde (387 mg, 3.65 mmol) in
THF (12 mL) was added tetraethoxytitanium (1.51 g,
6.6 mmol) and the mixture was stirred at rt for 16 h. A
saturated solution of KCl (4 mL) was added and the
suspension was filtered through Celite. The precipitate
was washed with ethyl acetate. The filtrate was dried
(MgSO4) and evaporated. Chromatography on silicagel
(CH2Cl2 and hexane 1:1 then AcOEt and hexane 1:1)
gave colorless oil (1.16 g, 92%). [h]D +87.1 (c 1.15,
Acknowledgements
1
CH2Cl2); IR (film) 1605, 1573 (CꢀN), 1069 (SꢀO); H
This work was financially supported by Institute of
Organic Chemistry Polish Academy of Sciences in
Warsaw grants for statute activity. The author would
like to thank Dr. Sc. Zofia Urban´czyk-Lipkowska for
X-ray measurement and analysis.
NMR (CDCl3) l 0.15 (s, 9H), 0.76–1.23 (m, 3H), 0.91
(d, J=6.4 Hz, 3H), 1.01 (s, 3H), 1.25 (s, 3H), 1.31–1.54
(m, 1H), 1.58–1.74 (m, 1H), 1.82–2.12 (m, 3H), 3.76
(ddd, J=4.2, 10.1, 10.6 Hz, 1H), 7.39–7.52 (m, 3H),