Etherification of (E)-1,3-diaryl- and (E)-1,3-diheteroaryl- prop-2-en-1-ols with primary and secondary alcohols over platinum on carbon

Article abstract of DOI:10.3184/030823407X24775

In the presence of platinum on carbon (Pt/C), (E)-1,3-diaryl- and (E)-1,3-diheteroaryl- prop-2-en-1-ols react with primary and secondary alcohols to give (E)-1,3-diaryl- and (E)-1,3-diheteroaryl- prop-2-enyl ethers.

Full text of DOI:10.3184/030823407X24775

528 RESEARCH PAPER
SEPTEMBER, 528–534
JOURNAL OF CHEMICAL RESEARCH 2007
Etherification of (E)-1,3-diaryl- and (E)-1,3-diheteroaryl- prop-2-en-1-ols
with primary and secondary alcohols over platinum on carbon
Thies Thiemann
Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1, Kasuga-koh-en, Kasuga-shi, Fukuoka 816-8580,
Japan
In the presence of platinum on carbon (Pt/C), (E)-1,3-diaryl- and (E)-1,3-diheteroaryl- prop-2-en-1-ols react with
primary and secondary alcohols to give (E)-1,3-diaryl- and (E)-1,3-diheteroaryl- prop-2-enyl ethers.
Keywords: etherification, platinum on carbon
In the predominant number of preparations of non-symmetric
ethers, only one of the components is an alcohol, while the
second component may be an alkene,1 a halide,2 tosylate,3
mesylate4 or otherwise activated ester.5 Only a few methods
are known where alcohols can be used for both components
or where the related transetherification leads to the selective
formation of non-symmetric ethers.6,7 In these cases,
it is necessary that the cross etherification between the
two different alcohols is the main reaction, while homo-
etherification is suppressed. As halides and activated esters
are derived mainly from the alcohols, and thus many of the
methods of etherification use costly starting materials, it
remains of interest to find new ways to prepare non-symmetric
ethers from the cross-etherification of two different alcohols.
of the DL- and meso forms of the head to head and head to
tail isomers could be isolated. These results indicate a charged
intermediate, which is symmetrical in the case of two identical
aryl groups.11
The relative ease with which the hydroxy group acts as
a leaving group in (E)-1,3-diarylprop-2-en-1-ols 5 in the
absence of a strong protonic acid led to the idea of reacting the
intermediate electrophile with nucleophiles. In the following,
the reaction of a number of (E)-1,3-diarylprop-2-en-1-ols and
(E)-1,3-dihetero-arylprop-2-en-1-ols with alcohols over Pt/C
is described (Scheme 3).
When a mixture of (E)-1,3-diarylprop-2-en-1-ol 5 and a
primary or secondary alcohol (10 equiv) is heated to 100°C
in the presence of a catalytic amount of Pt/C (0.12[5]mol%),
ethers 8 are formed in good yield within 30 min (Table 1).
In all cases, the alcohol component is used as the exclusive
solvent. The dimerisation of the (E)-diarylpropen-2-en-1-ols 5
is suppressed totally.
Monoactivated alcohols such as benzyl alcohol (7e) and allyl
alcohol (7f) can also be used in the reaction. These alcohols
do not undergo homo-etherification at 100°C and thus only
the desired products from cross-etherification are obtained. In
general, the reactions provide the products in good yield. One
exceptionisthereactionwith2-bromoethanol,wherenumerous
products are formed. When the halo-function is placed further
away from the reactive alcohol function, however, the product
forms again quickly and nearly quantitatively, as in the case
of 11-bromoundecanol (7k). t-Butanol (7g) does not react
well. Product 8g can be isolated, albeit in poor yield (25%).
However, in this case the dimerisation of 5b to ether 6c starts
to compete.
Recently,
I have reported that 4-alkoxyphenylalkyl-
carbinols (1) and cinnamylalkylcarbinols (3) dimerise in the
presence of Pt/C at 135°C to form ethers 2 and 4, respectively
(Scheme 1).8 Only very small amounts of olefins are formed
in these reactions in contrast to the reactions run under proton
catalysis. While reports have appeared of activation of oxygen
containing functionalities with salts of the platinum-metal
group, Pt(II) complexes9 and Pd(II) salts,10 little has been
communicated on the effect of Pt(0) on oxygen functionalities
for directed organic transformations. In order to assess whether
carbocations play a role in the reactions, the author turned to
(E)-1,3-diarylprop-2-en-1-ols 5 as starting materials. Use of
(E)-1,3-diarylprop-2-en-1-ols 5 would give access to allyl
cations as intermediates. Indeed, when (E)-1,3-diarylprop-2-
en-1-ols 5 are reacted over Pt/C at 100°C, the corresponding
ethers 6 form quickly. While (E)-1,3-diarylprop-2-en-1-ols
5 are also converted into dimeric ethers 6 in the absence
of Pt/C, when the reaction are run at 135°C, the reactions
progress significantly faster in the presence of Pt/C. (E)-1,3-
Diarylprop-2-en-1-ols 5 with identical aryl groups form the
ethers 6 as a mixture of DL- and meso-isomers. Where the
starting materials carried two different aryl groups, mixtures
The reaction of 5a with secondary alcohols such as
cyclopentanol (7h) takes a longer reaction time to complete
(90 min, 100°C), nevertheless giving 8h in good yield.
In the absence of Pt/C the etherification in general does not
proceed under reaction conditions otherwise identical to
1
1
R
R
RO
1
O
R
Pt/C
neat
135°C
RO
OR
OH
2
1
1
1
R
R
R
1
O
R
Pt/C
neat
135°C
R
R
OH
4
3
Scheme 1 Etherification of 4-alkoxyphenylalkylcarbinols and cinnamylalkylcarbinols in the presence of Pt/C.8
* Correspondent. E-mail: thies@cm.kyushu-a.ac.jp
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JOURNAL OF CHEMICAL RESEARCH 2007 529
MeO
MeO
OMe
MeO
Pt/C
100°C
O
O
+
neat
OH
6a
6b
(DL/meso) head-to tail
5a
(DL/meso) head-to head
OMe
Pt/C
100°C
O
neat
OH
6c
Scheme 2 Etherification of 1,3-diarylprop-2-en-1-ols by dehydrative dimerisation in the presence of Pt/C.
5b
R
R
R
R
1
R -OH
+
Pt/C
100°C
30 min
1
OH
OR
5b, c, f
R = H, Me, OMe
8a-i, 8n-s
1
R -OH
+
Pt/C
100°C
30 min
X
X
X
X
1
OH
OR
X = S, O
5d, e
8j-m
Scheme 3 Etherification of (E)-1,3-diaryl-and (E)-1,3-diheteroaryl-prop-2-en-1-ols.
those described above. Thus, heating a mixture of 5f with 2-
methoxyethanol (7b, cellusolve) at 100°C for 30 min yields
no product, whereas in the presence of Pt/C under otherwise
identical conditions, the product is formed in 92% yield.
The non-symmetric etherification with two different
alcohol components in the presence of Pt/C may be a more
general reaction and may proceed with substrates other than
(E)-1,3-diarylprop-2-en-1-ols. Diarylcarbinols also react under
the conditions, but their etherification proceeds more slowly.
Thus, the reaction of bis(4-tolyl)carbinol (9) with heptan-1-ol
provides ether 10 after 90 min. at 100°C only in 45% yield
(95% yield after 3 h at 130°C) (Scheme 4). The reaction of
triphenylmethanol (11) with alcohols such as heptan-1-ol does
not proceed with Pt/C (0.12[5] mol%) at 100°C (30 min).
This is in contrast to the etherification of triphenylmethanol
with alcohols under proton catalysis.12 Thus, reaction of
triphenylmethanol (11) with heptan-1-ol in presence of
p-toluenesulfonic acid leads after 30 min at 100°C to ether
12 in high yield (Scheme 4). This seems to indicate that the
steric factor is much more dominant in the case with Pt/C
O
OH
Pt/C, 90 min., 100°C: 45%
Pt/C, 3h, 130°C: 95%
OH
9
10
OH
OH
O
Pt/C, 30 min., 100°C: no reaction
p-TsOH, 30 min, 100°C: 88%
11
12
Scheme 4 Etherification reactions of 4-tolylbenzhydrol and of triphenylmethanol.
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530 JOURNAL OF CHEMICAL RESEARCH 2007
Table 1 Etherification of (E)-1,3-diaryl- and (E)-1,3-diheteroaryl-prop-2-en-1-ols over Pt/C
OH
OH
(95%)
O
5b
8a
7a
OH
MeO
OH
(91%)
O
5b
8b
7b
OMe
OH
OH
O
(94%)
5b
8c
7c
OH
OH
O
(92%)
5b
8d
7d
OH
OH
O
(90%)
5b
8e
7e
OH
OH
O
(95%)
5b
8f
7f
OH
OH
O
5b
8g
7g
(25%)
OH
OH
O
7h
(93%)
5b
5c
8h
MeO
OMe
MeO
OMe
OH
OH
O
(88%)
8i
7i
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JOURNAL OF CHEMICAL RESEARCH 2007 531
Table 1 Continued
S
S
OH
S
S
O
OH
5d
5d
8j
7d
7f
(93%)
OH
S
S
S
S
OH
O
8k
(90%)
OH
S
S
S
S
OH
O
5d
8l
7c
(94%)
O
O
OH
O
O
OH
O
5e
8m
(85%)
7c
OH
OH
O
(95%)
(92%)
8n
7c
7f
5f
OH
OH
O
8o
5f
OH
MeO
OH
O
(92%)
8p
7b
5f
OMe
OH
OH
H
11
C
5
OH
O
O
C H
7
15
(96%)
(96%)
(91%)
8q
7j
5f
5f
(CH )
2 10
Br
OH
(CH ) CH Br
2 10
2
8r
7k
OH
OH
O
8s
7l
5f
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532 JOURNAL OF CHEMICAL RESEARCH 2007
.
79.53; H, 8.05. C20H24O2 0.3H2O requires C, 79.59; H, 8.21).
than in the case of proton catalysis, which is plausible when
the activation of the substrate takes place on the surface or
near the surface of the activated carbon.13 While the actual
mechanism of the reaction is not yet ascertained, it is
known that alcohols adsorb on platinum [Pt(111)] with an
oxygen lone-pair orbital interaction with platinum of about
42 kJ mol-1.14 Thus, the activation of the hydroxyl group by
platinum may be sufficient for the etherification to proceed.
It must be noted, however, that in contrast to proton catalysis,
epoxyalcohols such as glycidol are stable under the current
conditions and can also be used as substrates in the reactions.
From the above, it could be shown that (E)-1,3-diarylprop-
2-en-1-ols and (E)-1,3-diheteroarylprop-2-en-1-ols react with
primary and secondary alcohols in the presence of Pt/C at
100°C. The reactions do not proceed in the absence of Pt/C
under otherwise identical conditions. Monoactivated alcohols
such as benzyl alcohol (7e) and allyl alcohol (7f) can also be
used as substrates in this transformation without formation of
products due to homo-etherification. Reactions were carried
out in a scale of 0.7 to 7.0 mmol of the substrates 5. Further
studies on the use of nucleophiles other than alcohols in this
reaction are underway.
(E)-1,3-Diphenylprop-2-enyl isobutyl ether (8c): Colourless oil;
(Found: M+ 266.1667. C19H22O requires M, 266.1671); nmax (neat/
cm-1) 3024, 2922, 1650, 1601, 1510, 1495, 1450, 1295, 1250, 1176,
1089, 966, 745, 697; dH (270 MHz, CDCl3) 0.94 (6H, d, 3J = 6.8 Hz,
2 CH3), 1.88–2.00 (1H, m), 3.18 (1H, dd, 2J = 8.6 Hz, 3J = 7.3 Hz),
3.30 (1H, dd, J = 8.6 Hz, J = 6.5 Hz), 4.88 (1H, d, J = 6.8 Hz),
6.27 (1H, dd, 3J = 15.9 Hz, 3J = 6.8 Hz), 6.61 (1H, d, 3J = 15.9 Hz),
7.21–7.42 (10H, m); dC (67.8 MHz, CDCl3) 19.5, 19.6, 28.7, 75.6,
82.6, 126.6 (2C), 126.8 (2C), 127.5, 127.6, 128.4 (2C), 128.5 (2C),
130.8, 130.9, 136.7, 141.7; MS (EI, 70 eV) m/z (%) = 266 (M+) (96),
210 (72), 193 (62), 115 (78), 105 (100).
2
3
3
(E)-1,3-Diphenylprop-2-enyl cyclopropylmethyl ether (8d):
Colourless oil; (Found: M+ 264.1515. C19H20O requires M, 264.1514);
n
max (neat/cm-1) 3026, 2922, 1602, 1512, 1494, 1450, 1301, 1250,
1173, 1086, 966, 745, 698; dH (270 MHz, CDCl3) 0.17–0.25 (2H, m),
0.50–0.58 (2H, m), 1.07–1.17 (1H, m), 3.05 (1H, dd, J = 10.0 Hz,
2
3J = 6.8 Hz), 3.17 (1H, dd, 2J = 10.0 Hz, 3J = 7.0 Hz), 4.75 (1H, d,
3J = 7.0 Hz), 6.12 (1H, dd, 3J = 15.4 Hz, 3J = 7.0 Hz), 6.37 (1H, d,
3J = 15.4 Hz), 7.00–7.21 (10H, m); dC (67.8 MHz, CDCl3) 3.1, 3.2,
10.8, 73.3, 82.3, 126.6 (2C), 126.9 (2C), 127.6, 127.7, 128.5 (4C),
130.6, 131.2, 136.6, 141.4; MS (EI, 70 eV) m/z (%) = 264 (M+) (17),
193 (53), 181 (50), 105 (100). (Found: C, 86.21; H, 7.61. C19H20O
requires C, 86.32; H, 7.63).
(E)-1,3-Diphenylprop-2-enyl benzyl ether (8e):19 Colourless oil;
(Found:M+ 300.1514.C22H20OrequiresM,300.1514);nmax(neat/cm-1)
3032, 2856, 1952 (ov), 1881 (ov), 1809 (ov), 1749 (ov), 1651,
1601, 1494, 1389, 1298, 1205, 1157, 1098, 964, 912, 742, 696;
Experimental
General
3
dH (270 MHz, CDCl3) 4.58 (2H, s), 5.01 (1H, d, J = 6.8 Hz), 6.33
3
3
3
(1H, dd, J = 15.7 Hz, J = 6.8 Hz), 6.63 (1H, d, J = 15.7 Hz),
7.20–7.45 (15H, m); dC (67.8 MHz, CDCl3) 70.1, 81.6, 126.6 (2C),
127.0 (2C), 127.5, 127.7 (4C), 128.4 (2C), 128.5 (4C), 130.3, 131.6,
136.6, 138.4, 141.1; MS (EI, 70 eV) m/z (%) = 300 (M+) (2.1), 209
(9.0), 193 (13), 181 (100), 105 (60).
Melting points were measured on a Yanaco microscopic hotstage and
are uncorrected. IR spectra were measured with JASCO IR-700 and
1
Nippon Denshi JIR-AQ2OM instruments. H and 13C NMR spectra
were recorded with a JEOL EX-270 spectrometer (1H at 270 MHz,
13C at 67.8 MHz). The chemical shifts are relative to TMS (solvent
CDCl3, unless otherwise noted). Mass spectra were measured with
a JMS-01-SG-2 spectrometer. Column chromatography was carried
out on Wakogel 300.
(E)-1,3-Diphenylprop-2-enyl allyl ether (8f):20 Colourless oil;
(Found: M+ 250.1361. C18H18O requires M, 250.1358); nmax (neat/
cm-1) 3060, 3026, 2924, 2856, 1651, 1601, 1494, 1450, 1300, 1251,
1084, 967, 918, 744, 696; dH (270 MHz, CDCl3) 4.04 (2H, m),
3
3
4.98 (1H, d, J = 7.0 Hz), 5.20 (1H, d, J = 10.5 Hz), 5.31 (1H, dd,
Substrates and reagents
J = 17.0 Hz, J = 2.1 Hz), 5.90–6.05 (1H, m), 6.30 (1H, dd, 3J = 15.9
Platinum on carbon (Wako, 5wt% Pt/C), the primary and secondary
alcohols as well as t-butanol and triphenylmethanol were acquired
commercially. (E)-1,3-Diarylprop-2-en-1-ols were synthesised by
Wittig reaction of benzaldehyde, anisaldehyde and 4-tolualdehyde
with the respective aroylmethylidenetriphenylphosphoranes under
solvent-reduced conditions15 and subsequent Luche reduction of
the chalcones.16 (E)-1,3-Di(thien-2-yl)prop-2-en-1-ol and (E)-1,3-
di(fur-2-yl)prop-2-en-1-ol were prepared by Schmidt condensation17
of 2-thienylaldehyde with 2-acetylthiophene and of 2-furylaldehyde
and 2-acetylfuran, all commercial products, and subsequent Luche
reduction.16 Bis(4-tolyl)methanol (9) was preparedfrom commercially
available 4,4'-dimethylbenzophenone by NaBH4-reduction.
3
3
Hz, J = 7.0 Hz), 6.62 (1H, d, J = 15.9 Hz), 7.22–7.42 (10H, m);
dC (67.8 MHz, CDCl3) 69.3, 81.7, 117.0, 126.6 (2C), 126.9 (2C),
127.6, 127.7, 128.5 (4C), 130.2, 131.4, 134.8, 136.6, 141.1; MS (EI,
70 eV) m/z (%) = 250 (M+) (7.4), 193 (36), 181 (76), 165 (33), 115
(77), 105 (100).
(E)-1,3-Diphenylprop-2-enyl t-butyl ether (8g):6b Colourless oil;
(Found: M+ 266.1676. C19H22O requires M, 266.1671); nmax (neat/
cm-1) 3060, 3024, 2970, 2924, 1650, 1598, 1493, 1192, 1098, 968,
745, 697; dH (270 MHz, CDCl3) 1.26 (9H, s, But), 5.19 (1H, d,
3J = 6.2 Hz), 6.31 (1H, dd, 3J = 15.9 Hz, 3J = 6.2 Hz), 6.52 (1H, d, 3J
= 15.9 Hz), 7.19–7.42 (10H, m); MS (EI, 70 eV) m/z (%) = 266 (M+),
210 (100), 193 (35), 181 (32), 178 (22), 165 (20), 115 (55).
(E)-1,3-Diphenylprop-2-enyl cyclopentyl ether (8h): Colourless
oil; (Found: M+ 278.1667. C20H22O requires M, 278.1667); nmax
(neat/cm-1) 3060, 3026, 2956, 2868, 1600, 1494, 1451, 1300, 1175,
1092, 966, 744, 696; dH (270 MHz, CDCl3) 1.69–1.74 (4H, m), 1.76–
1.79 (4H, m), 4.03–4.08 (1H, m), 4.97 (1H, d, 3J = 7.0 Hz), 6.29 (1H,
dd, 3J = 15.7 Hz, 3J = 7.0 Hz), 6.58 (1H, d, 3J = 15.7 Hz), 7.23–7.42
(10H, m); dC (67.8 MHz, CDCl3) 23.5, 23.6, 32.4, 32.5, 78.8, 80.3,
126.6, 126.9, 127.4, 127.6, 128.4, 128.5, 130.8, 131.1, 136.7, 141.9;
MS (EI, 70 eV) m/z (%) = 278 (M+) (13), 210 (100), 193 (79), 178
(31), 115 (94), 105 (72).
(E)-1,3-Diphenylprop-2-enyl propyl ether (8a)18: general procedure
for the etherification over Pt/C:
A mixture of (E)-1,3-diphenylprop-2-en-1-ol (5b) (1.52 g, 7.2 mmol),
propanol (4.30 g, 72 mmol, 10equiv) and 5 wt% Pt/C (36 mg, 1.8 mg
Pt, 9 × 10-3 mmol) was heated at 100°C for 30 min. Thereafter, the
solution was submitted directly to column chromatography on silica
gel (hexane/ether/CHCl3 5:1:1) to give 8a (1.72 g, 95%); colourless
oil; (Found: M+ 252.1512. C18H20O requires M, 252.1514); nmax (neat/
cm-1) 3086, 3026, 2962, 2932, 2870, 1494, 1451, 1084, 966, 743,
695; dH (270 MHz, CDCl3) 0.95 (3H, t, 3J = 7.5 Hz), 1.62–1.67 (2H,
m), 3.32–3.42 (1H, m), 3.47–3.53(1H, m), 4.90 (1H, d, 3J = 7.0 Hz),
6.30 (1H, dd, 3J = 15.7 Hz, 3J = 7.0 Hz), 6.60 (1H, d, 3J = 15.7 Hz),
7.21–7.39 (10H, m); dC (67.8 MHz, CDCl3) 10.7, 23.1, 70.4, 82.6,
126.6 (2C), 126.8 (2C), 127.5, 127.6, 128.4 (2C), 128.5 (2C), 130.7,
131.1, 136.7, 141.6; MS (EI, 70 eV) m/z (%) = 252 (M+) (21), 153
(52), 107 (57), 89 (64), 77 (100).
(E)-1,3-Bis(4-anisyl)prop-2-enyl ethyl ether (8i): Colourless oil;
(Found: M+ 298.1573. C19H22O3 requires M, 298.1569); nmax (neat/
cm-1)2970,2836,1609,1510,1459,1301,1247,1173,1088,1035,968,
831; dH (270 MHz, CDCl3) 1.24 (3H, t, 3J = 6.8 Hz, CH3), 3.38–3.48
(1H, m), 3.49–3.61 (1H, m), 3.79 (3H, s, OCH3), 3.80 (3H, s OCH3),
4.85 (d, 1H, 3J = 7.0 Hz), 6.16 (1H, dd, 3J = 15.9 Hz, 3J = 7.0 Hz),
3
3
6.50 (1H, d, J = 15.9 Hz), 6.82 (2H, d, J = 8.6 Hz), 6.89 (2H, d,
3J = 8.6 Hz), 7.30 (2H, d, J = 8.6 Hz), 7.31 (2H, d, J = 8.6 Hz);
dC (67.8 MHz, CDCl3) 15.4, 55.3, 63.8, 82.2, 113.8 (2C), 113.9 (2C),
127.8 (2C), 128.1 (2C), 128.7, 129.5, 130.5, 133.9, 159.0, 159.2;
MS (EI, 70 eV) m/z (%) = 298 (M+) (81), 253 (67), 135 (100).
(E)-1,3-Di(thien-2-yl)prop-2-enyl cyclopropylmethyl ether (8j):
Colourless oil; (Found: M+ 276.0643. C15H26O2S requires M,
276.0643); nmax (neat/cm-1) 3078, 3002, 2924, 2858, 1645, 1066,
958, 852, 830, 746, 697; dH (270 MHz, CDCl3) 0.18–0.26 (2H, m),
3
3
Further spectroscopic and physical data of the products
(E)-1,3-Diphenylprop-2-enyl 2-methoxyethyl ether (8b): Colourless
oil; (Found: M+ 268.1465. C18H20O2 requires M, 268.1463); nmax
(neat/cm-1) 3026, 2924, 1598, 1492, 1450, 1305, 1248, 1199, 1088,
1027, 967, 744, 697; dH (270 MHz, CDCl3) 3.39 (3H, s, OCH3), 3.59–
3.69 (4H, m), 4.97 (1H, d, 3J = 7.0 Hz), 6.32 (1H, dd, 3J = 15.7 Hz,
3J = 7.0 Hz), 6.60 (1H, d, 3J = 15.7 Hz), 7.24–7.43 (10H, m);
dC (67.8 MHz, CDCl3) 59.1, 67.8, 72.1, 83.1, 126.6 (2C), 126.9 (2C),
127.7 (2C), 128.5 (4C), 130.3, 131.5, 136.6, 141.1; MS (EI, 70 eV)
m/z (%) = 268 (M+) (33), 210 (84), 192 (71), 115 (100). (Found: C,
3
0.49–0.57 (2H, m), 1.03–1.18 (1H, m), 5.18 (1H, d, J = 6.7 Hz),
3.30 (1H, dd, 2J = 10.0 Hz, 3J = 7.0 Hz), 3.40 (1H, dd, 2J = 10.0 Hz,
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JOURNAL OF CHEMICAL RESEARCH 2007 533
3J = 6.5 Hz), 6.12 (1H, dd, 3J = 15.9 Hz, 3J = 7.5 Hz), 6.45 (1H, dd, 3J
= 15.9 Hz, 4J = 1.0 Hz), 6.94–6.99 (4H, m), 7.11 (1H, bd, 3J = 4.3 Hz),
7.27 (1H, dd, 3J = 4.9 Hz, 3J = 1.6 Hz); dC (67.8 MHz, CDCl3)
3.1 (2C), 10.6, 73.3, 77.5, 124.7, 124.8, 124.9, 125.3, 126.2, 126.6,
127.3, 129.2, 141.5, 145.2; MS (EI, 70 eV) m/z (%) = 276 (M+) (53),
247 (57), 205 (84), 193 (91), 111 (100).
3J = 15.9 Hz, 3J = 7.0 Hz), 6.54 (1H, d, 3J = 15.9 Hz), 7.08 (2H, d,
3J = 7.8 Hz), 7.15 (2H, d, 3J = 7.8 Hz), 7.24–7.29 (4H, m); dC (67.8
MHz, CDCl3) 14.1, 21.1, 21.2, 22.6, 26.2, 29.1, 29.9, 31.8, 68.7,
82.5, 126.5 (2C), 126.8 (2C), 129.1 (2C), 129.1 (2C), 129.9, 130.8,
134.1, 137.1, 137.3, 138.8; MS (EI, 70 eV) m/z (%) = 336 (M+) (41),
321 (25), 238 (15), 221 (38), 119 (100).
(E)-1,3-Di(thien-2-yl)prop-2-enyl allyl ether (8k): Colourless oil;
(Found: M+ 262.0491. C14H14OS2 requires M, 262.0486); nmax (neat/
cm-1) 3076, 3022, 2924, 2854, 1645, 1432, 1297, 1250, 1091, 960, 853,
832, 746, 696; dH (270 MHz, CDCl3) 4.05–4.08 (2H, m), 5.20 (1H,
d, 3J = 6.7 Hz), 5.21 (1H, m), 5.32 (1H, m), 5.87–6.03 (1H, m), 6.19
(1H, dd, 3J = 15.7 Hz, 3J = 6.7 Hz), 6.78 (1H, d, 3J = 15.7 Hz), 6.95–
(E)-1,3-Bis(4-tolyl)prop-2-enyl 11-bromoundecyl ether (8r):
Colourless oil; (Found: M+ 470.2191. C28H39O79Br requires M,
470.2184);
n
max (neat/cm-1) 2924, 2856, 1512, 1453, 1393, 1250,
1176, 1096, 964, 815, 749, 699; dH (270 MHz, CDCl3) 1.27–1.62
(16H, m), 1.78–1.88 (2H, m), 2.31 (3H, s, CH3), 2.34 (3H,. s, CH3),
3.40 (2H, t, 3J = 7.0 Hz), 3.41–3.52 (2H, m), 4.84 (1H, d, 3J = 7.0 Hz),
6.23 (1H, dd, 3J = 16.2 Hz, 3J = 7.0 Hz), 6.54 (1H, d, 3J = 16.2 Hz),
3
7.16 (4H, m), 7.17 (1H, bd, J = 4.6 Hz), 7.29 (1H, dd, J = 4.6 Hz,
3
3
J = 1.4 Hz); dC (67.8 MHz, CDCl3) 69.2, 76.9, 117.3, 124.8, 125.0,
125.1, 125.4, 126.3, 126.6, 127.4, 128.8, 134.5, 141.4, 144.8;
MS (EI, 70 eV) m/z (%) = 262 (M+) (11), 205 (44), 193 (33), 171
(30), 160 (28), 111 (100).
7.08 (2H, d, J = 8.1 Hz), 7.16 (2H, d, J = 7.6 Hz), 7.27 (4H, m);
dC (67.8 MHz, CDCl3) 18.2, 21.1, 21.2, 26.2, 28.8, 29.4, 29.4 (2C),
29.5, 29.9, 32.8, 34.0, 68.6, 82.5, 126.5 (2C), 126.8 (2C), 129.1 (2C),
129.2 (2C), 129.9, 130.8, 134.0, 137.1, 137.4, 138.7; MS (EI, 70 eV)
m/z (%) = 472 ([81Br]M+) (5.1), 470 ([79Br]M+) (5.5), 457 (4.7), 455
(4.5), 355 (8.6), 353 (8.9), 222 (100), 207 (99.9).
(E)-1,3-Di(thien-2-yl)prop-2-enyl isobutyl ether (8l): Colourless
oil; (Found: M+ 278.0794. C15H18OS2 requires M, 278.0799); nmax
(neat/cm-1) 3104, 3070, 2952, 2870, 1646, 1470, 1434, 1364, 1290,
1250, 1226, 1206, 1162, 1092, 957, 852, 829, 696; dH (270 MHz,
(E)-1,3-Bis(4-tolyl)prop-2-enyl cyclohexyl ether (8s): Colourless
oil; (Found: M+ 320.2144. C23H28O requires M, 320.2140); nmax
(neat/cm-1) 3022, 2924, 2856, 1514, 1453, 1297, 1178, 1072, 965,
800, 744, 700; dH (270 MHz, CDCl3) 1.20–2.02 (10H, m), 2.31 (3H,
s, CH3), 2.34 (3H, s, CH3), 3.32–3.42 (1H, m), 5.05 (1H, d, 3J = 7.0
Hz), 6.24 (1H, dd, 3J = 15.9 Hz, 3J = 7.0 Hz), 6.51 (1H, d, 3J = 15.9
Hz), 7.09 (2H, d, 3J = 8.1 Hz), 7.15 (2H, d, 3J = 8.1 Hz), 7.25–7.30
(4H, m); dC (67.8 MHz, CDCl3) 21.1, 21.2, 24.2, 24.3, 25.9, 32.5,
32.6, 74.6, 79.0, 124.5 (2C), 126.8 (2C), 129.0 (2C), 129.1 (2C),
130.4, 130.5, 134.0, 137.0, 137.3, 139.3; MS (EI, 70 eV) m/z (%) =
320 (M+) (31), 238 (82), 223 (47), 209 (37), 119 (100), 105 (47).
Bis(4-tolyl)methyl heptyl ether (10): Colourless oil; (Found: M+
310.2296. C22H30O requires M, 310.2297); nmax (neat/cm-1) 2924,
2852, 1613, 1511, 1094, 812, 764; dH (270 MHz, CDCl3) 0.88 (3H,
m), 1.28 (8H, m), 1.63 (2H, m), 2.31 (6H, s, 2 CH3), 3.42 (2H, t,
3
CDCl3) 0.93 (6H, d, J = 6.8 Hz), 1.84–1.99 (1H, m), 3.23 (1H, dd,
3
2
3
2J = 8.9 Hz, J = 6.8 Hz), 3.31 (1H, dd, J = 8.9 Hz, J = 6.5 Hz),
5.08 (1H, d, 3J = 6.5 Hz), 6.18 (1H, dd, 3J = 15.4 Hz, 3J = 6.5 Hz),
6.77 (1H, d, 3J = 15.4 Hz), 6.94–6.99 (4H, m), 7.17 (1H, bd,
3J = 4.9 Hz), 7.27 (1H, m); dC (67.8 MHz, CDCl3) 19.4, 19.5, 28.6,
75.6, 78.1, 124.6 (2C), 124.7, 125.2, 126.2, 126.5, 127.4, 129.3,
141.6, 145.5; MS (EI, 70 eV) m/z (%) = 278 (M+) (82), 222 (52),
205 (100), 171 (46), 111 (89), 97 (52). (Found: C, 64.69; H, 6.47.
C15H18OS2 requires C, 64.70; H, 6.52).
(E)-1,3-Di(fur-2-yl)prop-2-enyl isobutyl ether (8m): Colourless oil;
(Found: M+ 246.1252. C15H18O3 requires M, 246.1256); nmax (neat/
cm-1) 3118, 2956, 2868, 1490, 1470, 1366, 1330, 1255, 1226, 1174,
1151, 1072, 1012, 960, 927, 884, 804, 737; dH (270 MHz, CDCl3)
0.92 (6H, d, 3J = 6.7 Hz, 2 CH3), 1.82–1.97 (1H, m), 3.18–3.31 (2H,
3
3J = 6.5 Hz), 5.26 (1H, s), 7.11 (4H, d, J = 8.1 Hz), 7.24 (4H, d,
3
3
m), 4.92 (1H, d, J = 6.2 Hz), 6.26–6.36 (5H, m), 6.50 (1H, d, J =
15.9 Hz), 7.34 (1H, m), 7.40 (1H, m); dC (67.8 MHz, CDCl3) 19.4,
19.5, 28.6, 75.3, 75.7, 107.6, 108.5, 110.1, 111.3, 120.3, 125.7, 142.1,
142.4, 152.2, 153.9; MS (EI, 70 eV) m/z (%) = 246 (M+) (67), 190,
173 (100), 115 (47), 95 (50).
3J = 8.1 Hz); dC (67.8 MHz, CDCl3) 14.1, 21.1, 22.6, 26.2, 29.2 (2C),
29.9, 31.9, 69.1, 83.3, 126.9 (2C), 129.0 (4C), 136.8 (4C), 139.9
(2C); MS (EI, 70 eV) m/z (%) = 310 (M+, 19), 243 (25), 213 (27),
195 (100).
Triphenylmethyl heptyl ether (12)12:Amixture of triphenylmethanol
(11) (565 mg, 2.17 mmol), heptan-1-ol (2.5 g, 21.7 mmol, 10 eq.)
and p-toluenesulfonic acid (50 mg) were heated at 100ºC for 30 min.
The cooled solution was subjected to column chromatography on
silica gel (hexane/ether/CHCl3 6:1:1) to give 12 (684 mg, 88%);
colourless oil; nmax (neat/cm-1) 3060, 3020, 2928, 2858, 1600, 1511,
1492, 1449, 1072, 966, 898, 744, 701; dH (270 MHz, CDCl3) 0.87
(3H, t, 3J = 7.0 Hz), 1.23–1.32 (8H, m), 1.55–1.67 (2H, m), 3.04 (2H,
t, 3J = 6.8 Hz), 7.21–7.32 (9H, m), 7.43–7.46 (6H, m); dC (67.8 MHz,
CDCl3) 14.1, 22.6, 26.3, 29.2, 30.1, 31.8, 63.7, 86.3, 126.8 (3C),
127.7 (6C), 128.7 (6C), 144.5 (3C); MS (EI, 70 eV) m/z (%) = 358
(M+) (19), 281 (20), 243 (100), 183 (33), 165 (37), 105 (35).
(E)-1,3-Bis(4-tolyl)prop-2-enyl isobutyl ether (8n): Colourless oil;
(Found: M+ 294.1988. C21H26O requires M, 294.1984); nmax (neat/
cm-1) 3022, 2956, 2870, 1512, 1469, 1078, 967, 818, 800; dH (270
MHz, CDCl3) 0.92 (6H, 2d, 2 CH3), 1.80–1.99 (1H, m), 2.31 (3H,
s, CH3), 2.34 (3H, s, CH3), 3.13–3.18 (1H, m), 3.24–3.30 (1H, m),
4.82 (1H, d, 3J = 6.7 Hz), 6.22 (1H, dd, 3J = 15.9 Hz, 3J = 6.7 Hz),
3
3
6.55 (1H, d, J = 15.9 Hz), 7.09 (2H, d, J = 7.8 Hz), 7.15 (2H, d,
3J = 7.8 Hz), 7.27 (4H, m); dC (67.8 MHz, CDCl3) 19.5, 19.6, 21.1,
21.2, 28.7, 75.4, 82.54, 126.5 (2C), 126.8 (2C), 129.1 (2C), 129.2
(2C), 130.0, 130.7, 134.0, 137.1, 137.3, 138.8; MS (EI, 70 eV)
m/z (%) = 294 (M+) (56), 279 (21), 238 (24), 221 (50), 119 (100).
(E)-1,3-Bis(4-tolyl)prop-2-enyl allyl ether (8o): Colourless oil;
(Found: M+ 278.1672. C20H22O requires M, 278.1671); nmax (neat/
cm-1) 2924, 1651, 1616, 1509, 1455, 1412, 1302, 1179, 1076, 970,
928, 801, 748, 722; dH (270 MHz, CDCl3) 2.31 (3H, s, CH3), 2.34
(3H, s, CH3), 4.00–4.02 (2H, m), 4.93 (1H, d, 3J = 7.0 Hz), 5.18 (1H,
bd, J = 10.5 Hz), 5.29 (1H, bd, J = 17.3 Hz), 5.87–6.02 (1H, m), 6.23
(1H, dd, 3J = 15.9 Hz, 3J = 7.0 Hz), 6.55 (1H, d, 3J = 15.9 Hz), 7.08
(2H, d, 3J = 8.1 Hz), 7.15 (2H, d, 3J = 8.1 Hz), 7.25 (2H, m); dC (67.8
MHz, CDCl3) 21.1, 21.2, 69.1, 81.7, 116.8, 126.5 (2C), 126.9 (2C),
129.2 (4C), 129.4, 131.2, 133.9, 134.9, 137.3, 137.5, 138.3; MS (EI,
70 eV) m/z (%) = 278 (M+) (11), 209 (43), 119 (100).
Part of this work has been carried out within the framework of
a CREST program. Financial support from the Japan Science
andTechnology Corporation (JST) is gratefully acknowledged.
The author thanks Ms. Yasuko Tanaka, Institute of Materials
Chemistry and Engineering, Kyushu University, for the mass
and high resolution mass measurements. The elemental
analyses were carried out at the Centre of Analysis, Kyushu
University, Hakozaki Campus, Fukuoka.
(E)-1,3-Bis(4-tolyl)prop-2-enyl 2-methoxyethyl ether (8p):
Colourless oil; (Found: M+ 296.1776. C20H24O2 requires M,
296.1776); nmax (neat/cm-1) 2922, 1650, 1613, 1511, 1455, 1303,
1198, 1087, 969, 818, 750, 696; dH (270 MHz, CDCl3) 2.31 (3H,
s, CH3), 2.34 (3H, s, CH3), 3.39 (3H, s, OCH3), 3.55–3.66 (4H, m),
4.91 (1H, d, 3J = 7.0 Hz), 6.26 (1H, dd, 3J = 15.9 Hz, 3J = 7.0 Hz),
6.54 (1H, d, J = 15.9 Hz), 7.08 (2H, d, J = 7.8 Hz), 7.16 (2H, d,
3J = 7.8 Hz), 7.24–7.30 (4H, m); dC (67.8 MHz, CDCl3) 21.1, 21.2,
59.1, 67.7, 72.1, 83.1, 126.5 (2C), 126.9 (2C), 129. 1 (4C), 129.4,
131.2, 133.9, 137.3, 137.4, 138.2; MS (EI, 70 eV) m/z (%) = 296
(M+) (44), 281 (35), 238 (68), 221 (94), 205 (48), 119 (100).
Received 26 July 2007; accepted 24 September 2007
Paper 07/4765
doi: 10.3184/030823407X24775
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5
6
d
H (270 MHz, CDCl3) 0.88 (3H, t, 3J = 6.8 Hz), 1.26–1.30 (8H, m),
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PAPER: 07/4765

534 JOURNAL OF CHEMICAL RESEARCH 2007
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