1736
G. Righi et al. / Tetrahedron 56 (2000) 1733–1737
the cis-trans isomerisation of conjugated double bonds.7 As
demonstrated in Scheme 3 it can be very useful to resolve
some synthetic problems; currently under investigation are
other straightforward synthetic applications.
(2H, t, J7 Hz), 3.37 (1H, s). 13C NMR d (ppm): 13.78,
18.24, 22.28, 22.82, 24.60, 31.24, 40.83, 60.95, 65.25,
206.62. IR nmax 1707, 1235 cmϪ1. Anal. Calcd for
C10H18O2: C 70.55, H 10.66. Found: C 70.3, H 10.8.
Trans-4,5-oxyhexadecan-6-one (11). Colourless oil. 1H
NMR d (ppm): 0.85 (3H, t, J6.7 Hz), 0.95 (3H, t,
J7.3 Hz), 1.54–2.25 (20H, m), 2–2.25 (2H, m), 3.02
(1H, m), 3.18 (1H, d, J2 Hz). 13C NMR d (ppm): 13.73,
14.05, 19.10, 22.62, 23.07, 29.10, 29.25, 29.30, 29.39,
24.49, 31.83, 33.78, 37.14, 58.12, 59.54, 207.93. IR nmax
1705, 1250 cm1. Anal. Calcd for C16H30O2: C 75.54, H
11.89. Found: C 75.3, H 11.9.
Experimental
General methods
1H NMR and 13C NMR spectra were recorded on a Varian
XL 300 and Varian Gemini 200 spectrometers in CDCl3 as
the solvent, if not specified. All chemical shifts are reported
in parts per million against internal tetramethylsilane.
Coupling constants J were measured in Hz. All reactions
were monitored by TLC (Merck F254) or GC. GC analyses
were performed on a HP 5880A chromatograph equipped
with a OV 101 capillary column and a flame ionisation
detector. GC-MS analyses were performed on a HP 5890
chromatograph and HP 5971 as mass detector. Silica gel
Merck (200–400 mesh) was used for flash chromatography.
DMD solutions were prepared as reported by Adam7 and
co-workers using Oxone available from the Fluka company.
IR spectra were recorded in CHCl3 solution.
1
Trans-4-hexadecen-6-one (12). Colourless oil. H NMR d
(ppm): 0.89 (3H, t, J8.0 Hz), 0.92 (3H, t, J8.0 Hz), 1.2–
1.35 (12H, broad s), 1.4–1.6 (4H, m), 2.2 (2H, dq, J1.5,
7.5 Hz), 2.53 (2H, t, J8 Hz), 6.09 (1H, dt, J1.5, 13.8 Hz),
6.81 (1H, dt, J6.9, 13.8 Hz). 13C NMR d (ppm): 13.67,
14.09, 21.35, 22.65, 24.33, 29.29, 29.41, 29.46, 29.54,
31.86, 34.42, 40.09, 130.45, 147.03, 201.05. IR nmax 1670,
1700 cm1. Anal. Calcd for C16H30O: C 80.61, H 12.68.
Found: C 80.4, H 12.4.
Trans-2,3-oxyhexadecan-4-one (13). Colourless oil. 0.8–
1.7 (26H, m), 2.34 (2H, m), 3.10 (1H, m), 3.17 (1H, d,
J2.0 Hz). 13C NMR d (ppm): 14.05, 17.49, 22.62, 23.01,
29.09, 29.28, 29.38, 29.52, 29.57, 31.65, 37.09, 54.25,
60.51, 207.87. IR nmax 1255, 1708 cm1. Anal. Calcd for
C16H30O2: C 75.54, H11.89. Found: C 75.,7 H 11.6.
Starting materials
Olefins 2, 4, 6, 8, 17, 25, cis-stilbene and styrene are
commercially available. 17-Acetyl-testosterone 228 was
prepared by reacting testosterone 24 with a 1:1 mixture of
pyridine and acetic anhydride. All other olefins were
prepared as following reported.
1
Trans-2-hexadecen-4-one (14). Colourless oil. H NMR d
(ppm): 0.96 (3H, t, J7.5 Hz), 1.2–1.35 (16H, broad s), 1.6
(4H, m), 1.9 (3H, dd, J1.5, 7.0 Hz), 2.54 (2H, t,
J7.0 Hz), 6.15 (1H, dq, J1.5, 15.8 Hz), 6.85 (1H, dq,
J7.0, 15.8 Hz). 13C NMR d (ppm): 14013, 18.24, 22.69,
24.32, 29.34, 29.49, 29.62, 31.91, 40.06, 131.95, 142.32,
200.66. IR nmax 1665, 1698 cm1. Anal. Calcd for C16H30O:
C 80.61, H 12.68. Found: C 80.5, H 12.8.
General procedures
As a general procedure an enone was epoxidised by treat-
ment with 1.5 equiv. of a 0.9 M solution of DMD in acetone
previously prepared (see Ref. [2]), in the dark at rt for 8 h.
After evaporation of acetone under reduced pressure, the
crude was treated with Na2S2O3 sat. sol., extracted with
ethyl acetate, dried with anhydrous Na2SO4 and the solvent
evaporated.
Cis-2,3-oxyhexadecan-4-one (15). Colourless oil. 0.7–0.9
(6H, m), 1.15–1.3 (18H, broad s), 1.5–1.65 (2H, m), 2.48
(2H, t, J7.2 Hz), 3.29 (1H, quint, J5.0 Hz), 3.55 (1H, d,
J5.0 Hz). 13C NMR d (ppm): 12.91, 14.00, 22.59, 23.10,
29.12, 29.26, 29.35, 29.54, 31.82, 41.04, 54.06, 58.41,
206.12. IR nmax 1260, 1710 cm1. Anal. Calcd for
C16H30O2: C 75.54, H11.89. Found: C 75.5, H 11.7.
The double bond was restored by reacting 1 mmol of an
epoxide solution in 4 ml of acetone with NaI or LiI
(4 equiv.) and Amberlyst 15 (860 mg) for the required
time (see Table 1). The crude was concentrated, extracted
with diethyl ether, washed with brine, dried with anhydrous
Na2SO4 and the solvent evaporated in vacuo.
25-Hydroxy-4-cholesten-3-one (27). Prepared by the one
pot procedure: To 24 ml of a 0.08 M solution of DMD in
acetone 1 mmol of 4-cholesten-3-one 25 was added. After
24 h the mixture was concentrated and other 24 ml of DMD
solution were added. The mixture was left at rt for an addi-
tional 24 h, then 536 mg (4 mmols) of LiI and 860 mg of
Amberlyst 15 were added. After 5 h of stirring at rt the
analysis on TLC revealed the presence of the starting
material and of a polar product. Chromatography on silica
gel gave 50% yield of 25 (starting cholestanone) and 47% of
27 (94% overall yield calculated on the converted
compound). 27. White solid, mp 146–149 (from MeOH)
(lit. 146–15019); [a]D20ϩ79Њ (c0.2, CHCl3) (lit.,19
ϩ76Њ, c0.037, ϩ96Њ, c0.6). 1H NMR d (ppm): 0.7
(3H, s), 0.9 (3H, d, J6.5 Hz), 1.17 (3H, s), 1.2 (6H,
The two reactions can be performed in a ‘one pot’ pro-
cedure, when desired, such as for the transformation of 25
into 27 (see Experimental).
Products
Physical data for compounds 1,9 3,10 5,11 7,12 10,13 16,14
18,15 19,16 20,17 21, 22, 23, and 2418 are in agreement with
that reported in literature. All others were fully characterised.
2-Methyl-2,3-oxynonan-4-one (9). Colourless oil. 1H
NMR d (ppm): 0.85 (3H, t, J6 Hz), 1.2 (3H, s), 1.4 (3H,
s), 1.35–1.45 (4H, m), 1.55 (2H, m), 1.5–1.65 (2H, m), 2.48