L. Rougeau et al. / Tetrahedron 64 (2008) 9430–9436
R'
9435
overnight. The solution is then filtered on CeliteÒ and DME is
stripped off using a rotary evaporator. The obtained mixture is then
treated with 30 mL of dichloromethane (CH2Cl2) and 50 mL of
aqueous HCl 0.1 N in a separating funnel and then washed with
distilled water until pH 7. The organic phase is then dried on so-
dium sulfate, filtered and finally the solvent is evaporated with
a rotary evaporator to give generally a yellow mixture with more
than 90% yield.
R'
R'
R'
R'
hυ
R
R
R
R'
R'
R
R'
R
R
R
R'
R
white
During the coupling reaction three products are formed. The
separation step is easily realised by column chromatography with
CH2Cl2 as eluent. The mixed diynes are obtained pure with yield
higher than 40% and their structures have been confirmed by 1H
and 13C NMR. Two examples are reported, one for synthesis of
diynes starting from propargyl alcohol (m¼1) and one starting from
pent-4-yn-1-ol (m¼3).
blue
R
R'
R'
ΔT
R'
R
4.3.1. Trideca-2,4-diyn-1-ol (m¼1, n¼7)
R'
1H NMR (DMSO-d6):
d
¼5.35 (1H, s, OH), 4.09 (2H, s, OCH2), 2.13
R
(2H, t, 3J¼7 Hz, ^CCH2), 1.54 (2H, quint, CH2), 1.35 (10H, m, 5CH2),
0.88 (3H, t, 3J¼7 Hz, CH3).
R'
R
R'
R
13C NMR (DMSO-d6):
49.8 (OCH2), 31–22 (6CH2), 19.4 (^CCH2), 13.9 (CH3).
d
¼81.9 (Cq), 75.9 (Cq), 68.8 (Cq), 64.7 (Cq),
red
R
R
4.3.2. Pentadeca-4,6-diyn-1-ol (m¼3, n¼7)
Figure 14. Mechanism of the irreversible thermochromism phenomenon.
1H NMR (DMSO-d6):
d
¼4.44 (1H, s, OH), 3.46 (2H, t, 3J¼6.4 Hz,
OCH2), 2.26 (2H, t, 3J¼7.1 Hz, ^CCH2), 2.22 (2H, t, 3J¼7 Hz, ^CCH2),
1.66 (2H, quint, CH2), 1.50 (2H, quint, CH2), 1.32 (10H, m, 5CH2), 0.87
(3H, t, 3J¼7 Hz, CH3).
more than 90% yield. Further purification of the crude product by
column chromatography with a suitable eluent leads to the pure
compound. All NMR spectra are quite the same and one example is
given below.
13C NMR (DMSO-d6):
60.1 (OCH2), 31–22 (8CH2), 19.2 (^CCH2), 13.9 (CH3).
d
¼81.3 (Cq), 80.8 (Cq), 65.5 (Cq), 64.4 (Cq),
4.1.1. Eicosa-9,11-diyne (n¼7)
4.4. General procedure for the synthesis of diynesters D
1H NMR (CDCl3):
d
¼2.24 (4H, t, 3J¼7 Hz, 2^CCH2), 1.50 (4H,
quint, 2CH2), 1.26 (20H, m, 10CH2), 0.88 (6H, t, 3J¼7 Hz, 2CH3).
In a 100 mL three-necked flask, 10 mmol of alcohol, 12 mmol of
triethylamine and 20 mL of CH2Cl2 are introduced. Alkyl chloride
(11 mmol) in CH2Cl2 (10 mL) is added dropwise. The solution is
stirred for 1 h and washed with distilled water until pH 7. The or-
ganic phase is then dried on sodium sulfate, filtered, and the solvent
is evaporated with a rotary evaporator to give a white or yellow
product with yield higher than 90%. The diacetylenic compounds
are purified, when necessary, on a silica column with CH2Cl2 as el-
uent. The structure of diynes has been confirmed by 1H and 13C
NMR. Two examples are reported, one starting from propargyl al-
cohol (m¼1) and one starting from pent-4-yn-1-ol (m¼3).
13C NMR (CDCl3):
(2CH2), 19.3 (2^CCH2), 14.1 (2CH3).
d
¼77.5 (2Cq), 65.3 (2Cq), 32–25 (10CH2), 22.7
4.2. General procedure for the synthesis of symmetric
diyne-diols B
In a 100 mL three-necked flask, 20 mmol of the alkynol, 2 mmol
of tetramethylethylenediamine (TMEDA), 1 mmol of copper iodide
(CuI) and 30 mL of dimethoxyethane (DME) are introduced. The
mixture is then subjected to oxygen bubbling and stirred at 55 ꢁC
overnight. The solution is then filtered on CeliteÒ and DME is
stripped off using a rotary evaporator. The obtained mixture is then
treated with 30 mL of ethyl acetate and washed with brine. The
organic phase is then dried on sodium sulfate, filtered and finally
the solvent is evaporated with a rotary evaporator to give a solid
with more than 90% yield. Further purification of the crude product
by column chromatography with a suitable eluent leads to the pure
compound. As for A compounds, all NMR spectra are quite the same
and one example is given below.
4.4.1. Octanoyl trideca-2,4-diyn-1-oate (m¼1, n¼7, p¼6)
1H NMR (CDCl3):
d
¼4.71 (2H, s, OCH2), 2.30 (2H, t, 3J¼7.2 Hz,
O]CCH2), 2.24 (2H, t, 3J¼7 Hz, ^CCH2), 1.60 (2H, quint, CH2), 1.48
(2H, quint, CH2), 1.26 (18H, m, 9CH2), 0.88 (6H, t, 2CH3).
13C NMR (CDCl3):
d¼174.7 (CO), 83 (Cq), 75.4 (Cq), 72.9 (Cq), 63.4
(Cq), 52.8 (OCH2), 33.9 (O]CCH2), 32–22 (11CH2), 19.2 (^CCH2),
14.1 (2CH3).
4.4.2. Octanoyl pentadeca-4,6-diyn-1-oate (m¼3, n¼7, p¼6)
1H NMR (CDCl3):
d
¼4.15 (2H, t, 3J¼6.2 Hz, OCH2), 2.27 (2H, t,
4.2.1. Deca-4,6-diyn-1,10-diol (m¼3)
1H NMR (DMSO-d6):
d
¼3.74 (4H, t, 3J¼6.2 Hz, 2CH2OH), 2.39
3J¼7.1 Hz, O]CCH2), 2.24 (2H, t, 3J¼7 Hz, ^CCH2), 2.20 (2H, t,
3J¼7.1 Hz, ^CCH2), 1.84 (2H, quint, CH2), 1.54 (2H, quint, CH2), 1.47
(2H, quint, CH2), 1.25 (18H, m, 9CH2), 0.88 (6H, t, 2CH3).
(4H, t, 3J¼7 Hz, 2^CCH2), 1.80 (4H, quint, CH2), 1.74 (2H, s, OH).
13C NMR (DMSO-d6):
31.3 (2CH2), 15.6 (2^CCH2).
d
¼80.8 (2Cq), 65.6 (2Cq), 60.1 (2CH2OH),
13C NMR (CDCl3):
(OCH2), 34 (O]CCH2), 32-22 (11CH2), 19.3 (^CCH2), 14.9 (^CCH2),
d
¼175.9 (CO), 78.4 (2Cq), 66.8 (2Cq), 66.3
4.3. General procedure for the synthesis of diynols C
14.1 (2CH3).
In a 100 mL three-necked flask, 10 mmol of each alkyne, 2 mmol
of tetramethylethylenediamine (TMEDA), 1 mmol of copper iodide
(CuI) and 30 mL of dimethoxyethane (DME) are introduced. The
mixture is then subjected to oxygen bubbling and stirred at 55 ꢁC
4.5. 13C solid NMR studies
All 13C solid NMR spectra were carried out on a Bru¨ker
ARX300 spectrometer or a Bru¨ker AVANCE 300, equipped with