Generation of acetylides by treatment of fluoroethylenes with LDA: Preparation of propargyl alcohols

Article abstract of DOI:10.1055/s-2000-6336

The fluoroethylenes 3 produced the corresponding acetylides via dehydrofluorination and deprotonation by treatment with 2 equivalents of LDA in THF at 0 °C. These acetylides reacted with aldehydes and ketones to afford propargyl alcohols in good yields.

Full text of DOI:10.1055/s-2000-6336

452
PAPER
Generation of Acetylides by Treatment of Fluoroethylenes with LDA:
Preparation of Propargyl Alcohols
Kentaro Kataoka,a Sadao Tsuboi*b
aDepartment of Applied Chemistry, Faculty of Engineering, Okayama University, Tsushima, Okayama 700-8530, Japan
bDepartment of Environmental Chemistry and Materials, Faculty of Environmental Science and Technology, Okayama University,
Tsushima, Okayama 700-8530, Japan
Fax +81(86)2518898; E-mail: stsuboi6@cc.okayama-u.ac.jp
Received 4 November 1998; revised 28 September 1999
3Bu3P + CFCl3
[Bu3P+--CF-+PBu3] Cl-+ Bu3PCl2
Abstract: The fluoroethylenes 3 produced the corresponding
acetylides via dehydrofluorination and deprotonation by treatment
with 2 equivalents of LDA in THF at 0 °C. These acetylides reacted
with aldehydes and ketones to afford propargyl alcohols in good
yields.
1
2
NaOH (aq)
2
+ RCHO
[Bu3P+-CF=CHR] Cl-
R = phenyl, E/Z = 13/87
R = n-hexyl, E/Z = 94/6
HCF=CHR + Bu3PO
3
R = phenyl, E/Z = 87/13
R = n-hexyl, E/Z = 0/100
Key words: Wittig reaction, fluoroethylenes, dehydrofluorination,
acetylides, propargyl alcohols, fluorine, eliminations
Generation and Reaction of Monofluorinated Ylide 23
Scheme 1
Until recently, the chlorofluorocarbons (CFC) have been
produced and used in large quantities as an indispensable
material for various applications in daily life. They were
mostly used as propellants, refrigerants, foaming agents,
and washing agents. However, at present the production
and use of CFC are restricted for reasons of environmental
problems. It has been shown that CFC have potential to
cause ozone depletion and the greenhouse effect. Particu-
larly, five kinds of CFC, trichlorofluoromethane (CFC-
11), dichlorodifluoromethane (CFC-12), trichlorotrifluo-
roethane (CFC-113), dichlorotetrafluoroethane (CFC-
114), and chloropentafluoroethane (CFC-115), have
strong potentials as compared to other CFC’s. Therefore,
production of these CFC’s has been entirely stopped at
present, and immediate establishment of a decomposition
method is required.
ethylenes. This stereoselectivity can be explained by pre-
vious mechanistic proposals.6-9 In contrast to this stere-
ochemical result, aromatic aldehydes afforded the (Z)-
isomers of the vinylphosphonium salt, and the subsequent
basic hydrolysis afforded the (E)-fluoroethylenes. To ex-
plain this dramatic change in stereochemistry, an intramo-
lecular,
through-space,
charge-transfer
complex
involving one of the tributylphosphonium groups in the
phosphonium salt and the p-electrons of the aromatic ring
of the aldehyde was proposed.3
For both purposes of decomposition of 1 and its utilization
for organic synthesis, we performed the preparation of 3
according to the above method.3 The fluoroethylenes 3
were obtained from aldehydes in moderate yields and the
results are summarized in Table 1.
At present, the most general method is to treat with a high-
temperature plasma, but this procedure requires high tem-
perature of over 10000 °C.1 This fact gives an impression
that CFCs are chemically and thermally very stable sub-
stances. However, it is well known that CFCs were used
for organic synthesis under mild conditions, which indi-
cates that CFCs can be much more easily decomposed.
For example, Burton reported that CFC-11 (1) reacted
with 3 equivalents of tributylphosphine at 0 °C to afford
monofluorinated ylide 2 in excellent yields.2-5 This meth-
od is effective for the utilization and decomposition of 1,
however, the problem is that tributylphosphine is slightly
expensive. The ylide 2 reacted with aliphatic and aromatic
aldehydes at room temperature to give the corresponding
vinylphosphonium salts, and the subsequent basic hydro-
lysis afforded the corresponding fluoroethylenes 3 in
moderate yields (Scheme 1).3
Burton reported that aromatic aldehydes afforded the (E)-
fluoroethylenes,3 but the (Z)-3c was obtained as shown in
Entry 3 of Table 1. We have no explanation for it at
present. E/Z-ratios were determined by comparison of the
integral intensity of 19F NMR spectra and hydrogen-fluo-
In the case of aliphatic aldehydes, the (E)-isomers of the
vinylphosphonium salt were formed predominantly, and
the subsequent basic hydrolysis afforded the (Z)-fluoro-
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PAPER
Generation of Acetylides by Treatment of Fluoroethylenes with LDA
453
rine coupling constants. 19F NMR data are summarized in alcohols 6 using 2 equivalents of LDA and various alde-
Table 2.
hydes and ketones. Propargyl alcohols 6 were obtained in
good yields, and the results are summarized in Table 3.
The following consistent differences were observed in the
19F NMR spectra of the (E)-isomers, as compared to the
(Z)-isomers: (i) the chemical shifts of the fluorine are up-
field (29.5-31.8 vs 30.2-39.6 ppm), (ii) the hydrogen-
fluorine vicinal coupling constants are smaller
(3JH,F = 18.7-19.8 vs 43.3-46.1 Hz). On the other hand,
the hydrogen-fluorine geminal coupling constants are al-
most the same (2JH,F = 82.6-83.7 vs 82.7-86.0 Hz).
Based on these spectral criteria, the stereochemistry of 3
was assigned as described above.
Our report describes not only a utilization and decompo-
sition method of CFC 1 but also an effective method for
the conversion of aldehydes to acetylides. Use of CFC 1
will be entirely banned in the near future. But some other
methods for the synthesis of fluoroethylenes from alde-
hydes were reported, starting from, e. g. of perchloryl
fluoride,12 fluoroiodomethane,13 and
fluorodiiodo-
methane.14 These compounds can be used in the future.
There are many similar reports concerning the generation
of acetylides from halogenoethylenes.15 The halogenoeth-
ylenes could be prepared from the corresponding alde-
hydes by Wittig reaction. These reports resemble ours as
regards the synthetic pathway. The most common genera-
tion of acetylides is from dibromoethylenes,16 and this
method generally involves bromination of olefins. Our
method has the following advantages as compared to this
method: (i) acetylides are generated from the correspond-
ing aldehydes in two steps, (ii) in the case of a substrate
containing another unsaturated bond, the above method
incurs the problem that bromination may occur at another
site, but our method is free of such problem.
In organic synthesis, there are a few precedents for the use
of fluoroethylenes such as 3. For example, alkylation by
use of alkyl metal reagents involving defluorination10 and
conversion to carbonyl compounds11 were reported previ-
ously. In these reports, fluoroethylenes reacted as an elec-
trophile. Generations of a nucleophilic fluorovinyl metal
reagent from fluoroethylenes such as 3 has not been re-
ported. On the basis of the above findings, we attempted
the preparation of fluorovinyllithium reagents 4 by treat-
ment of 3 with 1 equivalent of LDA, and their addition to
carbonyl compounds (Scheme 2).
In conclusion, a synthetic method has been developed for
the generation of acetylides. The fluoroethylenes pro-
duced the corresponding acetylides via dehydrofluorina-
tion and deprotonation by treatment with 2 equivalents of
LDA in THF at 0 °C. These acetylides reacted with vari-
ous carbonyl compounds such as aldehydes and ketones to
afford propargyl alcohols in good yields.
Li
E
E+
LDA, THF
-100 °C
3
F
F
R1
R1
4
5
E+; aldehydes, ketones
-LiF
E
LDA, E+
R1
R1
6
All IR spectra were recorded on a JASCO FT/IR-5000 infrared
spectrophotometer as films. H NMR spectra were recorded on a
Scheme 2
1
Varian Gemini-200 spectrometer using CDCl3 (CHCl3, d = 7.26) as
a solvent. 19F NMR spectra were recorded on a Varian VXR-200
spectrometer using CDCl3 as a solvent and chemical shifts were re-
ported with hexafluorobenzene (d = 0) as an internal standard.
Splitting patterns are designated as "br, s, d, t, and m"; these sym-
bols indicate "broad, singlet, doublet, triplet, and multiplet", respec-
However, this attempt was unsuccessful because the inter-
mediate 4 is very unstable even at -100 °C and led only
to acetylide adducts 6. This result indicates that fluoroet-
hylenes 3 are useful as a source of acetylides. On the basis
of this result, we attempted the preparation of propargyl
Synthesis 1999, No. 3, 452–456 ISSN 0039-7881 © Thieme Stuttgart · New York

454
K. Kataoka, S. Tsuboi
PAPER
tively. Elemental analyses were performed on a Perkin-Elmer 2400
analyzer. Analytical TLC was performed on Merck silica gel 60 F254
plates and the plates were visualized with UV light and phospho-
molybdic acid (5% in EtOH). Merck silica gel 60 (40-63 µm) was
used for the flash chromatography. All reactions were carried out in
oven-dried, septum-capped flasks, and under N2. All liquid reagents
were transferred via oven-dried syringes. Solvents and reagents
were dried and distilled before use. THF was distilled from Na-ben-
zophenone ketyl immediately before use. CH2Cl2 was distilled from
CaH2. Normal reagent grade solvents were used for flash chroma-
tography.
1H NMR (200 MHz, CDCl3): d = 2.95 (s, 6 H), 5.49 (dd, J = 46.1,
5.2 Hz, 1 H), 6.54 (dd, J = 82.7, 5.2 Hz, 1 H), 6.68 (d, J = 9.0 Hz, 2
H), 7.41 (d, J = 9.0 Hz, 2 H).
19F NMR (188 MHz, CDCl3): d = 34.6 (dd, J = 82.7, 46.1 Hz, 1 F).
1-Fluoro-2-(3,4-methylenedioxyphenyl)ethylene (3d)
Prepared from 3,4-methylenedioxybenzaldehyde (3.705 g, 24.68
mmol) following the typical procedure described for 3a. The result-
ing oil was distilled at reduced pressure to give a clear colorless oil
(4.587 g, bp ~135 °C/5 Torr). Purification by flash chromatography
(hexane/EtOAc, 10:1) afforded 3d (2.850 g, 70%, E/Z = 88:12) as a
clear colorless oil; Rf 0.59 (hexane/EtOAc, 2:1). Elemental analyses
could not be performed because compound 3d was slightly unstable
and decomposed within a few days.
1-Fluoro-2-phenylethylene (3a); Typical Procedure
Modified Burton's method3 was used and the products were purified
by steam distillation and subsequent distillation at reduced pressure.
IR (neat): n = 2914, 1663, 1506, 1450, 1251, 1087, 1044 cm-1.
1H NMR (200 MHz, CDCl3): d = 5.51 (dd, J = 44.5, 5.4 Hz, 0.10
H), 5.94 (s, 2 H), 6.31 (dd, J = 18.7, 11.3 Hz, 0.90 H), 6.65-6.80
(m, 3 H), 7.06 (dd, J = 82.6, 11.3 Hz, 0.90 H).
19F NMR (188 MHz, CDCl3): d = 29.5 (dd, J = 82.6, 18.7 Hz, 0.90
F), 37.3 (dd, J = 83.0, 44.5 Hz, 0.10 F).
Trichlorofluoromethane (3.930 g, 28.60 mmol) was added to a so-
lution of (Bu)3P (17.36 g, 85.79 mmol) in anhyd CH2Cl2 (30 mL) at
0 °C under N2. The mixture was stirred at 0 °C for 1 h and then at
r.t. for 3 h. To the phosphonium salt formed was added benzalde-
hyde (2.424 g, 22.84 mmol) and the mixture was stirred at r.t. for 18
h. To the resulting solution was added aq 10% NaOH (35 mL) over
30 min and the mixture was stirred at r.t. for 17 h. The resulting so-
lution was acidified with 10% HCl and then extracted with CH2Cl2
(3 × 30 mL). The organic layer was dried (MgSO4) and the solvents
were removed in vacuo. The resulting oil was distilled at reduced
pressure to give a clear colorless oil (2.451 g, bp ~72 °C/16 Torr).
Purification by flash chromatography (hexane) afforded 3a (1.187
g, 43%, E/Z = 85:15) as a clear colorless oil; Rf 0.59 (hexane/
EtOAc, 4:1). The spectral data agreed with those in the previous re-
port.13
IR (neat): n = 3086, 1661, 1497, 1452 cm-1.
1H NMR (200 MHz, CDCl3): d = 5.60 (dd, J = 43.7, 5.5 Hz, 0.15
H), 6.39 (dd, J = 19.8, 11.4 Hz, 0.85 H), 6.64 (dd, J = 83.0, 5.5 Hz,
0.15 H), 7.15-7.32 (m, 5 H), 7.16 (dd, J = 83.6, 11.4 Hz, 0.85 H).
19F NMR (188 MHz, CDCl3): d = 31.8 (dd, J = 83.6, 19.8 Hz, 0.85
F), 39.6 (dd, J = 83.0, 43.7 Hz, 0.15 F).
1-Fluoroundec-1-ene (3e)
Prepared from decanal (3.786 g, 24.23 mmol) following the typical
procedure described for 3a. The resulting oil was distilled at re-
duced pressure to give a clear colorless oil (4.026 g, bp 78~153 °C/
14 Torr). Purification by flash chromatography (hexane) afforded
3e (1.904 g, 46%, E/Z = 0:100) as a clear colorless oil. Elemental
analyses could not be performed because compound 3e was slightly
unstable and decomposed within a few days.
IR (neat): n = 2924, 2860, 1673 cm-1.
1H NMR (200 MHz, CDCl3): d = 0.88 (m, 3 H), 1.15-1.40 (br, 14
H), 2.10 (br, 2 H), 4.72 (dtd, J = 43.3, 7.6, 4.7 Hz, 1 H), 6.44 (ddt,
J = 86.0, 4.7, 1.5 Hz, 1 H).
19F NMR (188 MHz, CDCl3): d = 30.2 (dd, J = 86.0, 43.3 Hz, 1 F).
1-Phenylhex-1-yn-3-ol (6a); Typical Procedure
BuLi (1.66 M in hexane, 1.26 mL, 2.09 mmol) was added to a solu-
tion of diisopropylamine (220 mg, 2.17 mmol) in anhyd THF (3
mL) over 5 min at 0 °C under N2. After stirring for 30 min at 0 °C,
3a (125 mg, 1.02 mmol) was added slowly at 0 °C and the mixture
was stirred for 30 min at 0 °C. To the resulting solution was added
slowly butanal (78 mg, 1.08 mmol) at 0 °C, and the mixture was
stirred at 0 °C for 30 min and then at r.t. for 2 h. The reaction was
quenched with H2O and neutralized with 10% HCl. The organic lay-
er was extracted with EtOAc (3 × 10 mL) and dried (MgSO4). The
solvents were removed in vacuo. Purification of the residue by flash
chromatography (hexane/EtOAc, 20:1-10:1) afforded 6a (141 mg,
79%) as a clear pale yellow oil; Rf 0.30 (hexane/EtOAc, 4:1). The
spectral data agreed with those in the literature.17
1-Fluoro-2-(4-methoxyphenyl)ethylene (3b)
Prepared from 4-methoxybenzaldehyde (3.407 g, 25.02 mmol) fol-
lowing the typical procedure described for 3a. The resulting oil was
distilled at reduced pressure to give a clear colorless oil (3.679 g, bp
72~110 °C/5 Torr). Purification by flash chromatography (hexane/
EtOAc, 10:1) afforded 3b3 (2.066 g, 54%, E/Z = 90:10) as a clear
colorless oil; Rf 0.60 (hexane/EtOAc, 2:1). The spectral data agreed
with those given in the literature.13
IR (neat): n = 3040, 3008, 2962, 2940, 1661, 1611, 1514, 1466,
1251, 1085, 1036 cm-1.
1H NMR (200 MHz, CDCl3): d = 3.80 (s, 3 H), 5.54 (dd, J = 44.9,
5.5 Hz, 0.10 H), 6.34 (dd, J = 19.6, 11.4 Hz, 0.90 H), 6.78-6.88 (m,
2 H), 7.09 (dd, J = 83.7, 11.4 Hz, 0.90 H), 7.10-7.20 (m, 2 H).
19F NMR (188 MHz, CDCl3): d = 29.0 (dd, J = 83.7, 19.6 Hz, 0.90
F), 36.4 (dd, J = 83.5, 44.9 Hz, 0.10 F).
IR (neat): n = 3400, 3060, 2960, 2876, 2230, 1601, 1491, 1444
cm-1.
1H NMR (200 MHz, CDCl3): d = 0.99 (t, J = 7.3 Hz, 3 H), 1.45-
1.68 (m, 2 H), 1.70-1.86 (m, 2 H), 1.91 (br, 1 H), 4.61 (br, 1 H),
7.25-7.38 (m, 3 H), 7.38-7.50 (m, 2 H).
1-(4-Dimethylaminophenyl)-2-fluoroethylene (3c)
Prepared from 4-dimethylaminobenzaldehyde (3.665 g, 24.57
mmol) following the typical procedure described for 3a. The result-
ing oil was distilled at reduced pressure to give a clear pale yellow
oil (5.953 g, bp ~133 °C/6 Torr). Purification by flash chromatogra-
phy (hexane/EtOAc, 10:1) afforded 3c (3.134 g, 77%, E/Z = 0:100)
as a clear pale yellow oil; Rf 0.64 (hexane/EtOAc, 2:1). Elemental
analyses could not be performed because compound 3c was slightly
unstable and decomposed within a few days.
1-(4-Dimethylaminophenyl)hex-1-yn-3-ol (6b)
Prepared from 3c (167 mg, 1.01 mmol) and butanal (80 mg, 1.11
mmol) following the typical procedure described for 6a. Purifica-
tion by flash chromatography (hexane/EtOAc, 10:1-2:1) afforded
6b (190 mg, 87%) as a clear orange oil; Rf 0.43 (hexane/EtOAc,
2:1).
IR (neat): n = 3400, 2962, 2934, 2874, 2224, 1611, 1524, 1448
cm-1.
IR (neat): n = 3094, 3026, 2982, 2924, 1663, 1613, 1526, 1448
cm-1.
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Generation of Acetylides by Treatment of Fluoroethylenes with LDA
455
1H NMR (200 MHz, CDCl3): d = 0.98 (t, J = 7.3 Hz, 3 H), 1.40-
1.90 (m, 5 H), 2.96 (s, 6 H), 4.59 (td, J = 6.2, 5.1 Hz, 1 H), 6.61 (d,
J = 9.0 Hz, 2 H), 7.30 (d, J = 9.0 Hz, 2 H).
forded 6g (134 mg, 61%) as a clear yellow oil; Rf 0.43 (hexane/
EtOAc, 2:1).
IR (neat): n = 3400, 2972, 2890, 1491, 1441, 1249, 1220, 1040
Anal. Calcd. for C14H19NO: C, 77.38; H, 8.81; N, 6.45. Found: C,
77.54; H, 8.90; N, 6.45.
cm-1.
1H NMR (200 MHz, CDCl3): d = 1.09 (t, J = 7.4 Hz, 3 H), 1.55 (s,
3 H), 1.57 (s, 1 H), 1.77 (q, J = 7.4 Hz, 2 H), 5.96 (s, 2 H), 6.71-
6.96 (m, 3 H).
1-(4-Dimethylaminophenyl)oct-1-yn-3-ol (6c)
Prepared from 3c (165 mg, 1.00 mmol) and hexanal (110 mg, 1.10
mmol) following the typical procedure described for 6a. Purifica-
tion by flash chromatography (hexane/EtOAc, 10:1-2:1) afforded
6c (221 mg, 90%) as a clear yellow oil; Rf 0.48 (hexane/EtOAc,
2:1).
Anal. Calcd. for C13H14O3: C, 71.54; H, 6.47. Found: C, 71.67; H,
6.48.
Pentadec-5-yn-4-ol (6h)
Prepared from 3e (173 mg, 1.00 mmol) and butanal (82 mg, 1.14
mmol) following the typical procedure described for 6a. Purifica-
tion by flash chromatography (hexane/EtOAc, 50:1-5:1) afforded
6h (175 mg, 78%) as a clear pale yellow oil; Rf 0.43 (hexane/
EtOAc, 4:1).
IR (neat): n = 3400, 2936, 2860, 2220, 1611, 1522, 1448 cm-1.
1H NMR (200 MHz, CDCl3): d = 0.90 (m, 3 H), 1.15-1.95 (m, 9 H),
2.97 (s, 6 H), 4.58 (q, J = 5.9 Hz, 1 H), 6.62 (d, J = 9.0 Hz, 2 H),
7.30 (d, J = 9.0 Hz, 2 H).
Anal. Calcd. for C16H23NO: C, 78.32; H, 9.45; N, 5.71. Found: C,
78.11; H, 9.44; N, 5.68.
IR (neat): n = 3400, 2930, 2858 cm-1.
1H NMR (200 MHz, CDCl3): d = 0.88 (t, J = 6.7 Hz, 3 H), 0.95 (t,
J = 7.1 Hz, 3 H), 1.15-1.80 (m, 19 H), 2.20 (td, J = 6.9, 1.9 Hz, 2
H), 4.36 (br, 1 H).
1-(4-Dimethylaminophenyl)-3-methylpent-1-yn-3-ol (6d)
Prepared from 3c (166 mg, 1.00 mmol) and butan-2-one (83 mg,
1.15 mmol) following the typical procedure described for 6a. Puri-
fication by flash chromatography (hexane/EtOAc, 10:1-2:1) af-
forded 6d (192 mg, 88%) as a clear yellow oil; Rf 0.44 (hexane/
EtOAc, 2:1).
Anal. Calcd. for C15H28O: C, 80.29; H, 12.58. Found: C, 80.55; H,
12.57.
Heptadec-7-yn-6-ol (6i)
Prepared from 3e (172 mg, 0.998 mmol) and hexanal (111 mg, 1.11
mmol) following the typical procedure described for 6a. Purifica-
tion by flash chromatography (hexane/EtOAc, 100:1-10:1) afford-
ed 6i (187 mg, 74%) as a clear pale yellow oil; Rf 0.45 (hexane/
EtOAc, 4:1).
IR (neat): n = 3400, 2978, 2936, 2816, 2216, 1611, 1522, 1446
cm-1.
1H NMR (200 MHz, CDCl3): d = 1.10 (t, J = 7.4 Hz, 3 H), 1.55 (s,
3 H), 1.61 (s, 1 H), 1.77 (q, J = 7.4 Hz, 2 H), 2.96 (s, 6 H), 6.61 (d,
J = 9.0 Hz, 2 H), 7.29 (d, J = 9.0 Hz, 2 H).
IR (neat): n = 3300, 2922, 2862 cm-1. The spectral data agreed with
Anal. Calcd. for C14H19NO: C, 77.38; H, 8.81; N, 6.45. Found: C,
77.33; H, 8.82; N, 6.72.
those in the literature.18
1H NMR (200 MHz, CDCl3): d = 0.80-0.95 (m, 6 H), 1.15-1.75
(m, 23 H), 2.20 (td, J = 6.8, 1.9 Hz, 2 H), 4.35 (br, 1 H).
1-(3,4-Methylenedioxyphenyl)hex-1-yn-3-ol (6e)
Prepared from 3d (167 mg, 1.01 mmol) and butanal (80 mg, 1.11
mmol) following the typical procedure described for 6a. Purifica-
tion by flash chromatography (hexane/EtOAc, 10:1-2:1) afforded
6e (160 mg, 73%) as a clear orange oil; Rf 0.41 (hexane/EtOAc,
2:1).
3-Methyltetradec-4-yn-3-ol (6j)
Prepared from 3e (175 mg, 1.02 mmol) and butan-2-one (84 mg,
1.16 mmol) following the typical procedure described for 6a. Puri-
fication by flash chromatography (hexane/EtOAc, 50:1-5:1) af-
forded 6j (132 mg, 59%) as a clear pale yellow oil; Rf 0.47 (hexane/
EtOAc, 4:1).
IR (neat): n = 3400, 2930, 2858 cm-1.
1H NMR (200 MHz, CDCl3): d = 0.88 (t, J = 6.7 Hz, 3 H), 1.02 (t,
J = 7.4 Hz, 3 H), 1.20-1.55 (m, 15 H), 1.44 (s, 3 H), 1.66 (q, J = 7.4
Hz, 2 H), 2.18 (t, J = 6.8 Hz, 2 H).
IR (neat): n = 3400, 2964, 2938, 2876, 1605, 1491, 1444, 1249,
1212, 1040 cm-1.
1H NMR (200 MHz, CDCl3): d = 0.98 (t, J = 7.3 Hz, 3 H), 1.35-
1.90 (m, 5 H), 4.58 (t, J = 6.5 Hz, 1 H), 5.97 (s, 2 H), 6.70-7.00 (m,
3 H).
Anal. Calcd. for C13H14O3: C, 71.54; H, 6.47. Found: C, 71.76; H,
6.47.
Anal. Calcd. for C15H28O: C, 80.29; H, 12.58. Found: C, 80.14; H,
12.72.
1-(3,4-Methylenedioxyphenyl)oct-1-yn-3-ol (6f)
Prepared from 3d (166 mg, 1.00 mmol) and hexanal (110 mg, 1.10
mmol) following the typical procedure described for 6a. Purifica-
tion by flash chromatography (hexane/EtOAc, 10:1-2:1) afforded
6f (173 mg, 70%) as a clear yellow oil; Rf 0.45 (hexane/EtOAc,
2:1).
References
(1) Mizuno, K.; Wakabayashi, T.; Koinuma, Y.; Aizawa, R.;
Kushiyama, S.; Kobayashi, S.; Ohuchi, H.; Yoshida, T.;
Kubota, Y.; et al. German Patent 3 936 516 (1990); Chem.
Abstr. 1990, 113, 158126.
(2) Burton, D. J.; Cox, D. G. J. Am. Chem. Soc. 1983, 105, 650.
(3) Cox, D. G.; Gurusamy, N.; Burton, D. J. J. Am. Chem. Soc.
1985, 107, 2811.
IR (neat): n = 3400, 2932, 2862, 1491, 1444, 1249, 1212, 1040
cm-1.
1H NMR (200 MHz, CDCl3): d = 0.90 (m, 3 H), 1.15-1.85 (m, 9 H),
4.56 (br, 1 H), 5.96 (s, 2 H), 6.70-7.00 (m, 3 H).
(4) (a) Jeong, I. H.; Burton, D. J.; Cox, D. G. Tetrahedron Lett.
1986, 27, 3709.
Anal. Calcd. for C15H18O3: C, 73.15; H, 7.37. Found: C, 73.16; H,
7.33.
(b) Burton, D. J.; Jeong, I. H. J. Fluorine Chem. 1993, 62,
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3-Methyl-1-(3,4-methylenedioxyphenyl)pent-1-yn-3-ol (6g)
Prepared from 3d (168 mg, 1.01 mmol) and butan-2-one (82 mg,
1.14 mmol) following the typical procedure described for 6a. Puri-
fication by flash chromatography (hexane/EtOAc, 10:1-2:1) af-
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456
K. Kataoka, S. Tsuboi
PAPER
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Article Identifier:
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1437-210X,E;1999,0,03,0452,0456,ftx,en;F08499SS.pdf
Synthesis 1999, No. 3, 452–456 ISSN 0039-7881 © Thieme Stuttgart · New York