10.1002/ejoc.201700922
European Journal of Organic Chemistry
CH2Cl2/MeOH 1:1 (2 mL) under argon atmosphere and dipotassium
azodicarboxylate (97 mg, 500 µmol) was added. The yellow
suspension was cooled to –78 °C and AcOH (90 mg, 86 µL in 1 mL
CH2Cl2) was dropwise added. The mixture was slowly warmed to
room temperature and stirred for 12 h. To the white suspension was
added saturated NH4Cl solution and the organic solvents were
evaporated under vacuum. The aqueous phase was extracted with
CH2Cl2 (3 × 5 mL). The combined organic phases were dried with
MgSO4 and evaporated under vacuum to dryness. The conversion
was determined by 1H NMR spectroscopy. The procedure described
above was still repeated seven times and 23 (34.5 mg, 64.3 µmol,
64%) was obtained as colourless oil. 23a, Me-20 axial; 23b, Me-20
80.4 (C-6), 65.4 (C-1), 41.1 (C-7), 40.0 (C-17), 39.2 (C-2), 37.4 (C-9),
35.1 (C-18), 34.0 (C-10), 33.0 (C-5), 32.9 (C-15), 32.1 (C-11), 28.8
(C-23, C-24), 26.5 (C-12), 22.9 (C-4), 20.6 (C-8), 20.5 (C-8), 20.3
(C-20), 20.0 (C-22), 19.7 (C-16), 19.6 (C-21), 11.9 (C-19) ppm. 2b,
1H NMR (500 MHz, CDCl3, 25 °C): δ = 4.10 (m, 1 H, 3-H), 3.67 (m, 1
H, 1-HA), 3.59 (m, 1 H, 1-HB), 1.98, 1.88 (m, 2 H, 12-H), 1.88 (t, J =
6.3 Hz, 2 H, 15-H), 1.82 (m, 1 H, 2-H), 1.66 (m, 2 H, 5-H), 1.62 (m, 2
H, 4-H), 1.57 (s, 3 H, 22-H), 1.53 (m, 2 H, 16-H), 1.40 (m, 1 H, 10-H),
1.39 (m, 2 H, 7-H), 1.38 (m, 4 H, 8-H, 17-H), 1.33, 1.13 (m, 2 H, 9-H),
1.25 (m, 2 H, 11-H), 1.08 (s, 3 H, 20-H), 1.00 (d, J = 6.9 Hz, 3 H, 19-
H), 0.98 (s, 6 H, 23-H, 24-H), 0.91 (d, J = 6.5 Hz, 3 H, 21-H) ppm.
13C NMR (125 MHz, CDCl3, 25 °C): δ = 137.8 (C-13), 126.5 (C-14),
82.5 (C-3), 80.3 (C-6), 65.4 (C-1), 40.0 (C-7, C-17), 39.3 (C-2), 37.6
(C-9), 35.1 (C-18), 33.8 (C-10), 32.9 (C-5, C-15), 32.1 (C-11), 28.8
(C-23, C-24), 26.3 (C-12), 24.5 (C-20), 22.8 (C-4), 21.3 (C-8), 21.0
(C-8), 20.0 (C-22), 19.7 (C-16), 19.6 (C-21), 11.8 (C-19) ppm. HRMS
(ESI): calcd. for C24H45O3 [M + H]+ 381.3363; found 381.3355.
equatorial. Rf = 0.35 (hexanes/CH2Cl2 9:2). FT-IR: = 2929, 2856,
1462, 1372, 1258, 1100, 1068, 1013, 973, 919, 882, 796, 681. 23a,
1H NMR (500 MHz, CDCl3, 25 °C): δ = 4.00 (m, 1 H, 3-H), 3.68 (dd, J
= 9.7, 4.8 Hz, 1 H, 1-HA), 3.63 (dd, J = 9.7, 5.7 Hz, 1 H, 1-HB), 1.99,
1.88 (m, 2 H, 12-H), 1.88 (t, J = 6.3 Hz, 2 H, 15-H), 1.77 (m, 2 H, 4-
H), 1.73 (m, 2 H, 5-H), 1.68 (m, 1 H, 2-H), 1.57 (s, 3 H, 22-H), 1.54
(m, 2 H, 16-H), 1.39 (m, 2 H, 17 H), 1.39 (m, 1 H, 10-H), 1.37 (m, 4
H, 7-H, 8-H), 1.33, 1.17 (m, 2 H, 9-H), 1.31 (s, 3 H, 20-H), 1.25 (m, 2
H, 11-H), 1.04 (m, 3 H, 1’-H), 1.04 (m, overl.,18 H, 2’-H), 1.01 (d, J =
6.9 Hz, 3 H, 19-H), 0.97 (s, 3 H, 23-H), 0.96 (s, 3 H, 24-H), 0.91 (d,
J = 6.5 Hz, 3 H, 21-H) ppm. 13C NMR (125 MHz, CDCl3, 25 °C): δ =
137.8 (C-13), 126.5 (C-14), 82.4 (C-3), 80.1 (C-6), 65.4 (C-1), 41.1
(C-7), 40.0 (C-17), 39.6 (C-2), 37.4 (C-9), 35.1 (C-18), 34.0 (C-10),
33.1 (C-5), 32.9 (C-15), 32.1 (C-11), 28.8 (C-23, C-24), 26.5 (C-12),
23.9 (C-4), 20.6 (C-8), 20.5 (C-8), 20.4 (C-20), 20.0 (C-22), 19.7 (C-
Diacarnoxide
C (1) and (2S)-methyl-2-((3R,6R)-6-methyl-6-(4-
methyl-6-(2,6,6-trimethylcyclohex-1-enyl)hexyl)-1,2-dioxan-3-
yl)propanoate (24): To a solution of 2 (21.3 mg, 56.1 µmol) in
MeCN (1 mL) was added H5IO6 (25.4 mg, 112.2 µmol) under
stirring. The resulting whitely suspension was cooled to 0 °C and
PCC (2.7 mg, 12 µmol) was added. The yellow-orange suspension
was stirred at 0 °C for 15 min and at room temp. for 1.5 h. The
reaction was quenched with half saturated NaCl solution (5 mL).
MTBE (15 mL) was added and the organic phase was separated.
The aqueous phase was extracted with MTBE (3 × 5 mL). The
combined organic phases were dried with MgSO4 and evaporated
under vacuum to dryness. The residue was dissolved in C6H6/MeOH
4:1 (1 mL) and TMSCHN2 (2 M in hexane, 40 µL, 80.1 µmol) was
added at room temp.. After 1 h the solvent was removed under
vacuum and the residue was purified by column chromatography
(silica gel; hexanes/EtOAc 3:1), to give an inseparable mixture of
two isomers of 1 and two isomers of 24 with a yield of 9.9 mg, 24.2
µmol, 43% as a waxy oil. 1, Me-20 axial; 24, Me-20 equatorial. Rf =
0.66 (hexanes/EtOAc 3:1). 1, 1H NMR (500 MHz, CDCl3, 25 °C): δ =
4.11 (m, 1 H, 3-H), 3.66 (s, 3 H, OMe), 2.62 (m, 1 H, 2-H), 1.99,
1.88 (m, 2 H, 12-H), 1.88 (t, J = 6.3 Hz, 2 H, 15-H), 1.66 (m, 2 H, 4-
H), 1.63 (m, 2 H, 5-H), 1.57 (s, 3 H, 22-H), 1.53 (m, 2 H, 16-H), 1.46
(m, 2 H, 7-H), 1.39 (m, 3 H, 10-H, 17-H), 1.36 (m, 2 H, 8-H), 1.32 (s,
3 H, 20-H), 1.25 (m, 2 H, 11-H), 1.24 (d, J = 6.6 Hz, 3 H, 19-H), 1.24,
1.13 (m, 2 H, 9-H), 0.98 (s, 6 H, 23-H, 24-H), 0.88 (d, J = 6.5 Hz, 3 H,
21-H) ppm. 13C NMR (125 MHz, CDCl3, 25 °C): δ = 174.6 (C-1),
137.8 (C-13), 126.5 (C-14), 81.6 (C-3), 80.4 (C-6), 51.8 (OMe), 42.9
(C-2), 40.1 (C-7), 40.0 (C-17), 37.5 (C-9), 35.1 (C-18), 34.0 (C-10),
32.4 (C-5), 32.8 (C-15), 31.8 (C-11), 28.8 (C-23, C-24), 26.5 (C-12),
22.8 (C-4), 20.7 (C-8), 20.6 (C-8), 20.3 (C-20), 19.9 (C-22), 19.7 (C-
16), 19.6 (C-21), 13.7 (C-19) ppm. 24, 1H NMR (500 MHz, CDCl3,
25 °C): δ = 4.11 (m, 1 H, 3-H), 3.69 (s, 3 H, OMe), 2.62 (m, 1 H, 2-
H), 1.99, 1.88 (m, 2 H, 12-H), 1.88 (t, J = 6.3 Hz, 2 H, 15-H), 1.66 (m,
2 H, 4-H), 1.63 (m, 2 H, 5-H), 1.57 (s, 3 H, 22-H), 1.53 (m, 2 H, 16-
H), 1.46 (m, 2 H, 7-H), 1.39 (m, 3 H, 10-H, 17-H), 1.36 (m, 2 H, 8-H),
1.25 (m, 2 H, 11-H), 1.24 (d, J = 6.6 Hz, 3 H, 19-H), 1.24, 1.13 (m, 2
H, 9-H), 1.13 (s, 3 H, 20-H), 0.98 (s, 6 H, 23-H, 24-H), 0.88 (d, J =
6.5 Hz, 3 H, 21-H) ppm. 13C NMR (125 MHz, CDCl3, 25 °C): δ =
174.6 (C-1), 137.8 (C-13), 126.5 (C-14), 81.2 (C-3), 80.3 (C-6), 52.0
(OMe), 43.1 (C-2), 40.0 (C-17), 39.3 (C-7), 37.6 (C-9), 35.1 (C-18),
33.9 (C-10), 32.8 (C-15), 32.1 (C-5), 31.8 (C-11), 28.8 (C-23, C-24),
26.3 (C-12), 24.5 (C-20), 22.8 (C-4), 21.3 (C-8), 21.0 (C-8), 19.9 (C-
22), 19.7 (C-16), 19.6 (C-21), 14.3 (C-19) ppm. HRMS (ESI): calcd.
for C25H44O4Na [M + Na]+ 431.3132; found 431.3125.
1
16), 19.6 (C-21), 18.2 (C-2’), 12.9 (C-19), 12.0 (C-1’) ppm. 23b, H
NMR (500 MHz, CDCl3, 25 °C): δ = 4.00 (m, 1 H, 3-H), 3.68 (dd, J =
9.7, 4.8 Hz, 1 H, 1-HA), 3.63 (dd, J = 9.7, 5.7 Hz, 1 H, 1-HB), 1.99,
1.88 (m, 2 H, 12-H), 1.88 (t, J = 6.3 Hz, 2 H, 15-H), 1.68 (m, 1 H, 2-
H), 1.63 (m, 2 H, 5-H), 1.62 (m, 2 H, 4-H), 1.57 (s, 3 H, 22-H), 1.54
(m, 2 H, 16-H), 1.39 (m, 5 H, 7-H, 10-H, 17-H), 1.37 (m, 2 H, 8-H),
1.33, 1.17 (m, 2 H, 9-H), 1.25 (m, 2 H, 11-H), 1.08 (s, 3 H, 20-H),
1.04 (m, 3 H, 1’-H), 1.04 (m, overl.,18 H, 2’-H), 1.01 (d, J = 6.9 Hz, 3
H, 19-H), 0.97 (s, 3 H, 23-H), 0.96 (s, 3 H, 24-H), 0.91 (d, J = 6.5 Hz,
3 H, 21-H) ppm. 13C NMR (125 MHz, CDCl3, 25 °C): δ = 137.8 (C-
13), 126.5 (C-14), 82.1 (C-3), 80.0 (C-6), 65.3 (C-1), 44.1 (C-7),
40.0 (C-7, C-17), 39.8 (C-2), 37.6 (C-9), 35.1 (C-18), 33.8 (C-10),
32.9 (C-5, C-15), 32.1 (C-11), 28.8 (C-23, C-24), 26.4 (C-12), 24.4
(C-20), 23.6 (C-4), 21.3 (C-8), 21.2 (C-8), 20.0 (C-22), 19.7 (C-16),
19.6 (C-21), 18.2 (C-2’), 12.8 (C-19), 12.0 (C-1’) ppm. HRMS (ESI):
calcd. for C33H65O3Si [M + H]+ 537.4697; found 537.4697.
(2R)-{(3R)-6-Methyl-6-[4-methyl-6-(2,6,6-trimethylcyclohex-1-
enyl)hexyl]-1,2-dioxane-3-yl}propan-1-ol (2): The TIPS-ether 23
(52 mg, 96.8 μmol) was dissolved in MeCN/THF 1:1 (3 mL) at room
temp. and HF 40% aq. (100 µL) was added. After 4 h saturated
NaHCO3 solution (3 mL) was added and the organic solvents were
evaporated under vacuum. The aqueous phase was extracted with
CH2Cl2 (3 × 3 mL). The combined organic phases were dried with
MgSO4 and evaporated under vacuum to dryness to give 2 (21.3 mg,
56.1 µmol, 58%) as a colourless oil. 2a, Me-20 axial; 2b, Me-20
equatorial. Rf = 0.33 (hexanes/EtOAc 3:1). FT-IR:
= 3409, 2924,
2854, 1438, 1376, 1260, 1089, 1018, 865, 798, 700. 2a, 1H NMR
(500 MHz, CDCl3, 25 °C): δ = 4.10 (m, 1 H, 3-H), 3.67 (m, 1 H, 1-HA),
3.59 (m, 1 H, 1-HB), 1.98, 1.88 (m, 2 H, 12-H), 1.88 (t, J = 6.3 Hz, 2
H, 15-H), 1.82 (m, 1 H, 2-H), 1.79 (m, 2 H, 4-H), 1.78 (m, 2 H, 5-H),
1.57 (s, 3 H, 22-H), 1.53 (m, 2 H, 16-H), 1.40 (m, 1 H, 10-H), 1.39 (m,
2 H, 7-H), 1.38 (m, 4 H, 8-H, 17-H), 1.33, 1.13 (m, 2 H, 9-H), 1.32 (s,
3 H, 20-H), 1.25 (m, 2 H, 11-H), 1.00 (d, J = 6.9 Hz, 3 H, 19-H), 0.98
(s, 6 H, 23-H, 24-H), 0.91 (d, J = 6.5 Hz, 3 H, 21-H) ppm. 13C NMR
(125 MHz, CDCl3, 25 °C): δ = 137.8 (C-13), 126.5 (C-14), 82.9 (C-3),
Submitted to the European Journal of Organic Chemistry
7
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