In-mediated allylation of α-keto esters with allyl halides

Article abstract of DOI:10.1081/SCC-100105896

The chemoselective reaction of α-keto esters with allyl halides, propargyl bromides, and allenyl bromide using indium metal afforded α-hydroxy-γ,δ-unsaturated esters in good to excellent yields under mild conditions.

Full text of DOI:10.1081/SCC-100105896

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In-MEDIATED ALLYLATION OF α-KETO ESTERS WITH
ALLYL HALIDES*
Phil Ho Lee a , Kooyeon Lee a & Sukbok Chang b
a Department of Chemistry , Kangwon National University , Chunchon, 200-701, S. Korea
b Department of Chemistry , Ewha Womans University , Seoul, 120-750, S. Korea
Published online: 16 Aug 2006.
To cite this article: Phil Ho Lee , Kooyeon Lee & Sukbok Chang (2001) In-MEDIATED ALLYLATION OF α-KETO ESTERS WITH
ALLYL HALIDES* , Synthetic Communications: An International Journal for Rapid Communication of Synthetic Organic
Chemistry, 31:20, 3189-3196, DOI: 10.1081/SCC-100105896
To link to this article: http://dx.doi.org/10.1081/SCC-100105896
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SYNTHETIC COMMUNICATIONS, 31(20), 3189–3196 (2001)
In-MEDIATED ALLYLATION
OF a-KETO ESTERS WITH
ALLYL HALIDES*
y
Phil Ho Lee,1, Kooyeon Lee,1
and Sukbok Chang2
1Department of Chemistry, Kangwon National
University, Chunchon 200-701, S. Korea
2Department of Chemistry, Ewha Womans University,
Seoul 120-750, S. Korea
ABSTRACT
The chemoselective reaction of a-keto esters with allyl halides,
propargyl bromides, and allenyl bromide using indium metal
afforded a-hydroxy-g,d-unsaturated esters in good to excellent
yields under mild conditions.
Metal-mediated addition of allyl halides to aldehydes or ketones is one
of the fundamental reactions in carbon-carbon bond formations, and has
become a well established method for the synthesis of homoallylic alcohols.1
The reactions of carbonyl compounds with allyl- and crotyl-metal reagents
*This paper is dedicated to Professor Chang Hwan Rhee on the occasion of his 60th
birthday.
yCorresponding author.
3189
Copyright & 2001 by Marcel Dekker, Inc.
www.dekker.com

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LEE, LEE, AND CHANG
derived from a variety of metals, in particular, have been widely investi-
gated.2 Recently, it has been reported that indium-mediated allylation of
carbonyl compounds in aqueous media afforded the corresponding homo-
allylic alcohols.3 Those reactions in aqueous media are of special interest
because they offer the possibility of environmentally benign reaction
conditions by reducing the burden of organic solvent disposal. Although
lots of examples on the indium-mediated allylation in aqueous media of
simple aldehydes and ketones have been reported,4 as far as we are aware,
no systematic studies of the chemoselective allylation into a-keto esters have
been published. As part of our continuing effort to expand the synthetic
utility of indium, we now report that indium metal is highly effective for
the chemoselective allylation of a-keto esters to afford a-hydroxy-g,d-unsat-
urated esters.
To find optimum conditions for indium-mediated allylation, ethyl
pyruvate was chosen as a standard substrate and it was reacted with allyl
bromide in the presence of indium in various solvents. Of the solvents tested,
the best results were obtained in MeOH/0.1N HCl(1:4). The indium-
mediated reaction of ethyl pyruvate with allyl bromide in MeOH/0.1 N
HCl(1:4) afforded ethyl 2-hydroxy-2-methyl-4-pentenoate in 90% yield
(Table 1, entry 1). However, the yields were decreased in other solvent
systems under the identical conditions despite longer reaction times. Also,
ethyl 3-methyl-2-oxobutyrate (entry 2) and ethyl benzoylformate (entry 3)
were reacted with allyl bromide under the identical conditions to produce
the desired compound 2 and 3, respectively. The reactions are completely
1
chemoselective and no addition to the ester group is observed by H NMR
spectroscopy of the crude reaction mixture.
Table 1 summarizes the experimental results and illustrates the
efficiency and scope of the present method.5 For the allyl bromides, the
presence of various substituents at the b position, such as methyl (entry
4), dimethyl (entry 6), phenyl (entry 7), bromo (entry 8) or ethoxycarbonyl
(entry 9) exhibited little effects on both the reaction rates and product yields.
Good to excellent yields were obtained in reactions of various a-substituted
allyl bromides as well. In case of methallyl dichloride (entry 10), the desired
allylation occurred followed by reduction of allyl chloride to produce
the dechlorinated compound 10. It is especially noteworthy that a substrate
having an acidic hydrogen such as 2-(bromomethyl)acrylic acid was
also reacted to provide the corresponding a-hydroxy-g,d-unsaturated
esters 11 in good yield (entry 11). In case of propargyl bromide (entry 12),
regioisomeric products were produced. However, 3-bromo-1-(trimethylsi-
lyl)-1-propyne gave the allenylated compound 14 as a sole product
(entry 13). The protocol developed here could also be applied to a reaction
with allenyl bromide. For example, ethyl pyruvate was reacted with

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a-KETO ESTERS AND ALLYL HALIDES
3191
Table 1. Reaction of a-Keto Esters with a Variety of Allyl Halides Using Indium
Metal

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LEE, LEE, AND CHANG
4-bromo-3-[(trimethylsilyl)methyl]-1,2-butadiene6 under the identical con-
ditions to give the desired compound 15 in 77% yield (entry 14).
In conclusion, the reaction of a-keto esters with allyl halides, propar-
gyl bromides, and allenyl bromide with indium metal afforded a-hydroxy-
g,d-unsaturated esters in MeOH/0.1N HCl at room temperature in good to
excellent yields. It offers a complementary approach to the aldol reaction.
The present method may serve as an alternative to the existing synthetic
methods because of mild reaction condition and some advantages of indium
metal such as ease of handling, high reactivity and selectivity, low toxicity
and operational simplicity. Further studies on the enantioselective synthesis
of a-hydroxy-g,d-unsaturated esters and other 1,n-dicarbonyl compounds
using indium catalyst are now in progress.
EXPERIMENTAL SECTION
Ethyl 2-hydroxy-2-methyl-4-pentenoate (1) To a solution of ethyl pyr-
uvate (116.0 mg, 1.0 mmol) and allyl bromide (181.0 mg, 1.5 mmol) in 5 mL
of MeOH/0.1N HCl (1:4) was added indium (115.0 mg, 1.0 mmol: indium
power (99.99%) purchased from Aldrich Chem Co.) in one portion.
The reaction mixture was stirred vigorously at room temperature for 2 hr.
The reaction mixture was quenched with saturated aqueous NaHCO3
solution. The aqueous layer was extracted with ether (3 ꢀ 25 mL) and the
combined organic layer washed with water (20 mL), brine (20 mL), dried
with MgSO4, filtered and concentrated in vacuo. The residue was purified by
silica gel column chromatography (hexane/EtOAc ¼ 10/1) leading to ethyl
2-hydroxy-2-methyl-4-pentenoate (142.0 mg, 90%): 1H NMR (200 MHz,
CDCl3) d 5.79 (m, 1H), 5.14 (m, 2H), 4.22 (q, J ¼ 7.32 Hz, 2H), 2.99 (s,
1H), 2.30 (m, 2H), 1.41 (s, 3H), 1.29 (t, J ¼ 7.02 Hz, 3H); 13C NMR
(100 MHz, CDCl3) d 176.61, 132.52, 119.07, 74.30, 61.86, 44.71, 25.54,
14.26; IR (film) 3490, 3010, 2960, 1700, 1430, 1360, 1240, 1200,
1150 cmÀ1; HRMS(CI) calcd for C8H15O3 [M þ H]þ 159.1022, found
159.1035.
Ethyl 2-hydroxy-2-isopropyl-4-pentenoate (2) 1H NMR (400 MHz,
CDCl3) d 5.75 (m, 1H), 5.10 (d, J ¼ 7.82 Hz, 1H), 5.06 (s, 1H), 4.23 (q,
J ¼ 7.13 Hz, 2H), 3.17 (s, 1H), 2.53, 2.50 (dd, J ¼ 6.34, 13.79 Hz, 1H),
2.40, 2.36 (dd, J ¼ 8.19, 13.70 Hz, 1H), 1.99 (m, 1H), 1.29 (t, J ¼ 7.14 Hz,
3H), 0.97 (d, J ¼ 6.83 Hz, 3H), 0.85 (d, J ¼ 6.83 Hz, 3H); 13C NMR
(100 MHz, CDCl3) d 176.33, 133.08, 118.47, 79.68, 61.75, 41.55, 35.09,
17.42, 15.91, 14.31; IR (film) 3500, 3020, 2940, 1700, 1420, 1400,
1240 cmÀ1; HRMS(CI) calcd for C10H19O3 [M þ H]þ 187.1335, found
187.1315.

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a-KETO ESTERS AND ALLYL HALIDES
3193
Ethyl 2-hydroxy-2-phenyl-4-pentenoate (3) 1H NMR (400 MHz,
CDCl3) d 7.61 (d, J ¼ 7.72 Hz, 2H), 7.36 (t, J ¼ 7.08 Hz, 2H), 7.35 (m,
1H), 5.81 (m, 1H), 5.17, 5.14 (dd, J ¼ 17.08, 9.76 Hz, 2H), 4.21 (m, 2H),
3.77 (s, 1H), 2.99, 2.96 (dd, J ¼ 7.76, 13.99 Hz, 1H), 2.78, 2.74 (dd, J ¼ 6.49,
14 Hz, 1H), 1.27 (t, J ¼ 7.16 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 174.62,
141.42, 132.40, 128.25, 127.78, 125.35, 119.30, 77.89, 62.50, 44.17, 14.10; IR
(film) 3480, 3020, 2960, 1710, 1430, 1410, 1240 cmÀ1; HRMS(CI) calcd for
C13H17O3 [M þ H]þ 221.1179, found 221.1148.
Ethyl 2-hydroxy-2,3-dimethyl-4-pentenoate (4) 1H NMR (200 MHz,
CDCl3) d 5.78 (m, 1H), 5.14–4.99 (m, 2H), 4.24 (m, 2H), 3.15 (s, 1H),
2.46 (m, 1H), 1.32 (t, J ¼ 3.66 Hz, 3H), 1.08 (d, J ¼ 6.72 Hz, 3H), 0.96 (d,
J ¼ 6.72 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 177.18, 177.06, 139.34,
138.60, 116.87, 116.09, 76.41, 76.14, 65.98, 61.99, 61.93, 46.32, 46.16,
24.37, 23.59, 15.36, 15.30, 14.30, 13.58; IR (film) 3520, 3020, 2960, 1700,
1430, 1410, 1240 cmÀ1; HRMS(CI) calcd for C9H17O3 [M þ H]þ 173.1179,
found 173.1185.
Ethyl 2-(20-cyclohexenyl)-2-hydroxy-2-methylpropanoate (5) H NMR
1
(200 MHz, CDCl3) d 5.90–5.85 (m, 1H), 5.83–5.37 (m, 1H), 4.26 (q,
J ¼ 7.02 Hz, 2H), 2.68 (s, 1H), 1.99 (m, 1H), 1.89–1.82 (m, 2H), 1.52–1.41
(m, 2H), 1.39 (s, 3H), 1.31 (t, J ¼ 7.02, 3H); 13C NMR (100 MHz, CDCl3) d
177.12, 176.93, 130.97, 130.36, 126.35, 125.29, 76.48, 61.92, 61.80, 43.88,
43.81, 25.02, 24.11, 23.59, 22.95, 22.44, 21.97, 21.84, 14.28; IR (film) 3520,
3030, 2960, 2940, 1710, 1440, 1420, 1250 cmÀ1; HRMS(CI) calcd for
C11H19O3 [M þ H]þ 199.1335, found 199.1325.
1
Ethyl 2-hydroxy-2,3,3-trimethyl-4-pentenoate (6) H NMR (400 MHz,
CDCl3) d 5.94, 5.90 (dd, J ¼ 10.96, 16.00 Hz, 1H), 5.00 (d, J ¼ 3.35 Hz, 1H),
4.96 (d, J ¼ 9.71 Hz, 1H), 4.17 (m, 2H), 3.41 (s, 1H), 1.28 (s, 3H), 1.24
(t, J ¼ 7.19, 3H), 1.02 (s, 3H), 1.01 (s, 3H); 13C NMR (100 MHz, CDCl3)
d 176.80, 144.22, 113.56, 78.80, 62.20, 43.82, 22.79, 22.33, 21.11, 14.62; IR
(film) 3490, 3020, 2950, 1690, 1410, 1360, 1240, 1120 cmÀ1; HRMS(CI) calcd
for C10H19O3 [M þ H]þ 187.1335, found 187.1321.
Ethyl
2-hydroxy-2-methyl-3-phenyl-4-pentenoate
(7)
1H NMR
(200 MHz, CDCl3) d 7.28 (m, 5H), 6.32 (m, 1H), 5.28 (d, J ¼ 3.97, 1H),
5.24 (d, J ¼ 11.60, 1H), 4.04 (m, 2H), 3.58 (d, J ¼ 9.77, 1H), 3.29 (s, 1H),
1.50 (s, 3H), 1.20 (t, J ¼ 6.71, 3H); 13C NMR (100 MHz, CDCl3) d 176.25,
140.12, 136.23, 128.62, 128.42, 127.22, 118.40, 76.74, 61.97, 58.10, 24.77,
14.11; IR (film) 3500, 3020, 2940, 1700, 1440, 1410, 1240, 1140 cmÀ1
;
HRMS(CI) calcd for C14H19O3 [M þ H]þ 235.1335, found 235.1328.
trans-Ethyl
5-bromo-2-hydroxy-2-methyl-4-pentenoate
(8-trans)
1H NMR (200 MHz, CDCl3) d 5.77 (m, 1H), 5.16 (m, 1H), 4.60 (d,
J ¼ 10.07 Hz, 1H), 4.25 (m, 2H), 2.45 (m, 2H), 1.43 (s, 3H), 1.31 (t,
J ¼ 7.33 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 176.64, 132.52, 119.14,

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LEE, LEE, AND CHANG
74.32, 61.91, 44.73, 25.58, 14.29; IR (film) 3500, 3020, 2960, 1720, 1420,
1400, 1240 cmÀ1; HRMS(CI) calcd for C8H14Br1O3 [M þ H]þ 237.0128,
found 237.0126.
cis-Ethyl 5-bromo-2-hydroxy-2-methyl-4-pentenoate (8-cis) 1H NMR
(200 MHz, CDCl3) d 6.15 (m, 1H), 5.24 (d, J ¼ 27.45 Hz, 1H), 5.16 (m,
1H), 4.25 (m, 2H), 2.45 (m, 2H), 1.53 (s, 3H), 1.33 (t, J ¼ 7.33 Hz, 3H);
13C NMR (100 MHz, CDCl3) d 173.42, 135.02, 119.02, 74.32, 61.54, 44.73,
24.88, 14.22; IR (film) 3500, 3020, 2960, 1720, 1420, 1400, 1240 cmÀ1
;
HRMS(CI) calcd for C8H14Br1O3 [M þ H]þ 237.0128, found 237.0126.
Diethyl 2-hydroxy-2-methyl-3-vinylsuccinate (9) 1H NMR (200 MHz,
CDCl3) d 5.94 (m, 1H), 5.38 (d, J ¼ 10.07 Hz, 1H), 5.30 (d, J ¼ 17.09 Hz,
1H), 4.26 (q, J ¼ 7.33 Hz, 2H), 4.16 (q, J ¼ 7.02 Hz, 2H), 3.47 (d,
J ¼ 9.77 Hz, 1H), 1.35 (s, 3H), 1.31 (t, J ¼ 7.33 Hz, 3H), 1.26 (t,
J ¼ 7.32 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 175.84, 172.49, 130.85,
121.61, 74.94, 61.97, 61.30, 57.35, 23.91, 14.15, 14.08; IR (film) 3500,
3020, 2960, 1710, 1430, 1410, 1240 cmÀ1; HRMS(CI) calcd for C11H19O5
[M þ H]þ 231.1234, found 231.1222.
Ethyl 2-hydroxy-2,4-dimethyl-4-pentenoate (10) 1H NMR (400 MHz,
CDCl3) d 4.81 (s, 1H), 4.68 (s, 1H), 4.15 (m, 2H), 2.55 (d, J ¼ 13.72 Hz,
1H), 2.39 (d, J ¼ 13.57 Hz, 1H), 1.69 (s, 3H), 1.36 (s, 3H), 1.24 (t,
J ¼ 7.22 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 177.18, 141.67, 115.36,
74.89, 62.18, 48.19, 26.86, 24.27, 14.56; IR (film) 3500, 3020, 2940, 1700,
1430, 1350, 1440 cmÀ1; HRMS(CI) calcd for C9H17O3 [M þ H]þ 173.1179,
found 173.1185.
1
4-Ethoxycarbonyl-4-hydroxy-2-methylenylpentanoic acid (11) H NMR
(200 MHz, CDCl3) d 6.44 (s, 1H), 5.82 (s, 1H), 4.21 (m, 2H), 2.86 (d,
J ¼ 14.04 Hz, 1H), 2.69 (d, J ¼ 14.04 Hz, 1H) 1.47 (s, 3H), 1.30 (t,
J ¼ 7.02 Hz, 3H); 13C NMR (100 MHz, CDCl3) d 176.10, 172.37, 135.03,
131.67, 74.30, 62.14, 41.20, 25.56, 14.13; IR (film) 3010, 3940, 1700, 1670,
1610, 1420, 1400, 1140, 950 cmÀ1; HRMS(CI) calcd for C9H15O5 [M þ H]þ
203.0921, found 203.0938.
Ethyl 2-hydroxy-2-methyl-4-pentynoate (12) 1H NMR (400 MHz,
CDCl3) d 4.23 (q, J ¼ 3.58, 2H), 3.16 (s, 1H), 2.63 (d, J ¼ 16.59 Hz, 1H),
2.52 (d, J ¼ 16.59 Hz, 1H) 2.03 (m, 1H), 1.43 (s, 3H), 1.28 (t, J ¼ 5.04, 3H);
13C NMR (100 MHz, CDCl3) d 175.55, 79.34, 73.93, 71.71, 62.50, 31.21,
25.44, 14.51; HRMS(CI) calcd for C8H13O3 [M þ H]þ 157.0866, found
157.0877.
1
Ethyl 2-hydroxy-2-methyl-3,4-pentadienoate (13) H NMR (400 MHz,
CDCl3) d 5.32 (t, J ¼ 6.79, 1H), 4.92 (m, 2H), 4.23 (q, J ¼ 3.58, 2H), 3.16 (s,
1H), 1.49 (s, 3H), 1.26 (t, J ¼ 7.36, 3H); 13C NMR (100 MHz, CDCl3) d
206.91, 175.48, 96.36, 79.34, 72.87, 62.54, 25.24, 14.51; HRMS(CI) calcd
for C8H13O3 [M þ H]þ 157.0866, found 157.0854.

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a-KETO ESTERS AND ALLYL HALIDES
Ethyl 2-hydroxy-2-methyl-3-trimethylsilyl-3,4-pentadienoate
3195
(14)
1H NMR (400 MHz, CDCl3) d 4.55 (s, 2H), 4.26 (q, J ¼ 6.83 Hz, 2H), 1.56
(s, 3H), 1.31 (t, J ¼ 7.19, 3H), 0.16 (s, 9H); 13C NMR (100 MHz, CDCl3) d
209.03, 176.21, 101.42, 75.31, 71.82, 62.12, 26.65, 14.28, 0.03; IR (film) 3480,
3020, 2940, 1910, 1700, 1430, 1400, 1240, 1120 cmÀ1; HRMS(CI) calcd for
C11H21O3Si1 [M þ H]þ 229.1261, found 229.1251.
Ethyl 2-hydroxy-2-methyl-4-[(trimethylsilyl)methyl]-4,5-hexadienoate
(15) 1H NMR (200 MHz, CDCl3) d 4.65 (m, 2H), 4.21 (m, 2H), 3.33
(s, 1H), 2.52–2.21 (m, 2H), 1.43 (s, 3H), 1.35 (s, 2H), 1.30 (t, J ¼ 7.02 Hz,
3H), 0.03 (s, 9H); 13C NMR (100 MHz, CDCl3) d 207.18, 176.43, 143.04,
96.37, 75.75, 74.93, 61.67, 44.51, 26.67, 26.13, 22.58, 14.20, À1.16; IR (film)
3450, 3020, 2940, 1700, 1400, 1260, 1140 cmÀ1; HRMS(CI) calcd for
C13H25O3Si1 [M þ H]þ 257.1574, found 257.1561.
ACKNOWLEDGMENT
This work was supported by Korea Research Foundation Grant
(KRF-99-005-D00048). The gas chromatograms were provided by GC facil-
ity, supported by Research Center for Advanced Mineral Aggregate
Composite Products.
REFERENCES
1. (a) Trost, B.M. Comprehensive Organic Synthesis, Pergamon Press,
Oxford, 1991. p. 1. (b) Yamamoto, Y.; Asao, N. Chem. Rev. 1993,
93, 2207.
2. (a) Yamamoto, Y. Acc. Chem. Res. 1987, 20, 243. (b) Hoffmann, R.W.
Angew. Chem. Int. Ed. Engl. 1982, 21, 555. (c) Yamamoto, Y.;
Maruyama, K. Heterocycles 1982, 18, 357. (d) Courtois, G.; Miginiac,
L.J. Organomet. Chem. 1974, 69, 1.
3. (a) Li, C.-J. Tetrahedron 1996, 52, 5643. (b) Li, C.-J.; Chan, T.-H.
Organic Reactions in Aqueous Media, Wiley, New York, 1997. (c) Li,
C.-J. Chem. Rev. 1993, 93, 2023. (d) Li, C-J.; Chan, T.-H. Tetrahedron
1999, 55, 11149. (e) Li, C.-J. and Chan, T.-H. Tetrahedron Lett. 1991,
32, 7017. (f) Isaac, M.B.; Chan, T.-H. Tetrahedron Lett. 1995, 36, 8957.
(g) Beuchet, P.; Marrec, N.L.; Mosset, P. Tetrahedron Lett. 1992, 33,
5959. (h) Loh, T.-P.; Ho, D.S.; Xu, K.-C.; Sim, K.-Y., Tetrahedron
Lett. 1997, 38, 865. (i) Chan, T.-H.; Lu, W. Tetrahedron Lett. 1998,
39, 8605.

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4. (a) Kim, E.; Gordon, D.M.; Schmid, W.; Whitesides, G.M. J. Org.
Chem. 1993, 58, 5500. (b) Bindra, W.H.; Prenner, R.H.; Schmid, W.
Tetrahedron 1994, 50, 749. (c) Chan, T.-H.; Lee, M.-C. J. Org. Chem.
1995, 60, 4228. (d) Li, X.-R.; Loh, T.-P. Tetrahedron: Asymmetry 1996,
7, 1535. (e) Loh, T.-P.; Ho, D.S.-C.; Chua, G.-L.; Sim, K.-Y. Synlett.
1977, 563. (f) Yi, X.-H.; Meng, Y.; Li, C.-J. Chem. Commun. 1988, 449.
(g) Li, C.-J.; Lu, Y.-Q. Tetrahedron Lett. 1995, 36, 2721. (h) Nair, V.;
Jayan, C.N. Tetrahedron Lett. 2000, 41, 1091.
5. All new compounds have satisfactory analytical data including 1H,
13C-NMR, MS, and IR spectroscopy.
6. 4-Bromo-3-[(trimethylsilyl)methyl]-1,2-butadiene was prepared from
2-butyn-1,4-diol according to the following scheme.
Received in the UK September 5, 2000

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