Room temperature Fe(NO3)3·9H 2O/TEMPO/NaCl-catalyzed aerobic oxidation of homopropargylic alcohols

Article abstract of DOI:10.1016/j.tet.2013.08.082

A practical and eco-friendly aerobic oxidation of homopropargylic alcohols using Fe(NO₃)₃·9H₂O/TEMPO/NaCl as catalysts at room temperature under atmospheric pressure was developed affording corresponding homopropargylic ke

Full text of DOI:10.1016/j.tet.2013.08.082

Tetrahedron 69 (2013) 10161e10167
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Room temperature Fe(NO3)3$9H2O/TEMPO/NaCl-catalyzed aerobic
oxidation of homopropargylic alcohols
,
,c,
Jinxian Liu a b, Shengming Ma a
*
a Shanghai Key Laboratory of Green Chemistry and Chemical Process, Department of Chemistry, East China Normal University, 3663 North Zhongshan
Lu, Shanghai 200062, PR China
b College of Chemistry and Materials Science, Longyan University, Longyan 364000, PR China
c State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai
200032, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 28 June 2013
Received in revised form 13 August 2013
Accepted 24 August 2013
Available online 9 September 2013
A practical and eco-friendly aerobic oxidation of homopropargylic alcohols using Fe(NO3)3$9H2O/
TEMPO/NaCl as catalysts at room temperature under atmospheric pressure was developed affording
corresponding homopropargylic ketones with moderate to good yields. Aryl, heteroaryl as well as alkyl
1,2-allenic ketones were obtained by the isomerization of corresponding terminal homopropargylic
ketones through column chromatographic workup on silica gel.
Ó 2013 Elsevier Ltd. All rights reserved.
Keywords:
Aerobic oxidation
Homopropargylic alcohol
Iron nitrate
TEMPO
NaCl
1. Introduction
1992, Marshall and co-workers reported the oxidation of homo-
propargylic alcohols by DesseMartin reagent or Swern oxidation
Numerous oxidation methods towards alcohols have been re-
ported using at least a stoichiometric amount of oxidants, such as
MnO2, chromium oxides, DMSO as well as hypervalent iodine
compounds in literature.1 However, those conventional oxidants
would produce almost the same amount of oxidant-derived waste
causing serious environmental problems. As a mild and natural
terminal oxidant, molecular oxygen would be the best alternative
from the viewpoint of eco-friendly and economic advantages.2 On
the other hand, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) has
been reported as the catalyst to oxidize alcohols with various oxi-
dants including molecular oxygen in literature.3 Therefore, de-
veloping novel protocol for the oxidation of alcohols using
molecular oxygen as terminal oxidant under mild conditions is
highly required.
followed by a basic workup to afford corresponding allenic ke-
tones in good yields;4 In 1998, Hashmi and co-workers found that
oxidation of homopropargylic alcohols by DesseMartin reagent
followed by a chromatographic workup on silica gel would also
yield allenic ketones conveniently in good yields;5 Fan’s group
have developed a RuCl3-catalyzed protocol using TBHP as terminal
oxidant in [bmin]PF6 at 80 ꢀC to afford allenic ketones in moderate
yields;6 Alsters7a and Fan7b have developed two different Cr-
catalyzed protocols for the oxidation of homopropargylic alco-
hols affording corresponding allenic ketones with good yields in-
dependently. However, as far as we know, there is no catalytic
aerobic oxidation protocol for such transformation reported in
literature.
Recently, this group has established a general protocol for
the aerobic oxidation of alcohols bearing a wide range of sub-
strates especially for propargylic alcohols under mild conditions
using Fe(NO3)3$9H2O/TEMPO/NaCl as catalyst, yielding corre-
sponding aldehydes or ketones in good to excellent yields.8
Therefore, we wish to investigate the application of this green
and efficient protocol for the oxidation of homopropargylic al-
cohols (Scheme 1).
Homopropargylic ketones, which could be easily isomerized to
allenic ketones, could be synthesized by the oxidation of corre-
sponding alcohols, and there are few reports for this trans-
formation using at least stoichiometric amount of oxidants.4e7 In
* Corresponding author. Fax: þ86 21 6260 9305; e-mail address: masm@sio-
c.ac.cn (S. Ma).
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.08.082

10162
J. Liu, S. Ma / Tetrahedron 69 (2013) 10161e10167
chromatographic workup
on silica gel
Ph
Ph
O
O
3a
2a
87%
Scheme 3. Isomerization of the homopropargylic ketone.
Scheme 1. Oxidation of homopropargylic alcohols.
We defined 10 mol % Fe(NO3)3$9H2O, 10 mol % TEMPO, and
10 mol % NaCl in DCE at room temperature under atmospheric
pressure for the aerobic oxidation of the homopropargylic alcohols
followed by the chromatographic workup on silica gel as standard
procedure for study on the substrate scope of various terminal
homopropargylic alcohols. The results are summarized in Scheme
4. When R¼Ph, p-C2H5C6H4, p-iPrC6H4, p-ClC6H4, p-BrC6H4, o-
MeO, m-MeO, p-MeO, or 2, 4, 6-(MeO)3, the substrates were effi-
ciently oxidized and isomerized to corresponding allenic ketones
(3a, b, dej). It was worth noting that when R¼heteroaryl groups,
such as 2-thienyl and 2-furyl, the corresponding allenic ketones
could also be obtained with good yields (3k and 3l). When
2. Results and discussion
We have initially tried this aerobic oxidation of 1-phenyl-butyl-
3-yl-1-ol (Scheme 2). To our surprise, when 10 mol
%
Fe(NO3)3$9H2O, 10 mol % TEMPO, and 10 mol % NaCl (the role of Clꢁ
in this reaction is not quite clear yet, it is probably working as a li-
gand to Fe3þ to accelerate the oxidation8a) were used, this reaction
could work smoothly at room temperature under atmospheric
pressure of molecular oxygen affording corresponding homo-
propargylic ketone 2a in 91% NMR yield.
.
10 mol% Fe(NO3)3 9H2O
10 mol% TEMPO
Ph
Ph
10 mol% NaCl
DCE, O2 (balloon), rt, 4 h
HO
1a
O
2a
NMR yield: 91%
Scheme 2. Initial trail of the iron-catalyzed aerobic oxidation of 1-phenyl-butyl-3-yl-
1-ol.
Based on this observation, we tried to optimize the reaction
conditions based on solvent effect, catalyst loading as well as dif-
ferent nitrate, the results were summarized in Table 1. Compared to
toluene, ethyl acetate, and THF, the full conversion and highest
NMR yield could be achieved when using DCE as solvent (Table 1,
entries 1e4). Lowering the catalyst to
5 mol % each of
Fe(NO3)3$9H2O/TEMPO/NaCl, only 76% NMR yield of 2a and 14%
recovery of homopropargylic alcohol in 20 h was observed (Table 1,
entry 5). When Cu(NO3)2$3H2O was used instead of
Fe(NO3)3$9H2O, the yield was obviously lower (Table 1, entry 6).
Table 1
Optimization of the aerobic oxidation of 1-phenyl-butyl-3-yl-1-ol (1a)
.
10 mol% Fe(NO3)3 9H2O
10 mol% TEMPO
10 mol% NaCl
Solvent, O2 (balloon), rt
Ph
Ph
HO
1a
O
2a
Entry Solvent
Time (h) Yield of 2a (%, NMR) Recovery of 1a (%, NMR)
1
2
3
DCE
Toluene
Ethyl acetate 20
THF
DCE
DCE
4
20
91
89
52
25
76
52
d
4
26
73
14
36
4
20
20
20
5a
6b
a
5 mol % each of the three catalysts were used here.
Cu(NO3)2$3H2O was used instead of Fe(NO3)3$9H2O.
b
Interestingly, after chromatographic workup procedure allenic
ketone 3a was isolated in 87% (Scheme 3).4,5
Scheme 4. The scope of aerobic oxidation of homopropargylic alcohols.

J. Liu, S. Ma / Tetrahedron 69 (2013) 10161e10167
10163
R¼naphthyl, c-hexyl, and alkyl, moderate yields of the corre-
sponding allenic ketones could be obtained (3c, m, and n).
We next investigated on the oxidation of non-terminal single-
substituted homopropargylic alcohols (Scheme 5). TBDMS pro-
tected-homopropargylic alcohols 1o could be oxidized to corre-
2987, 1960, 1932, 1649, 1596, 1578, 1448, 1416, 1348, 1276,
1214 cmꢁ1; MS (EI) m/z 144 (Mþ, 9.33), 105 (100).
The following compounds (3ben, 2o) were prepared according
to 3a.
sponding homopropargylic ketone 2o in
a
moderate yield.
4.2.2. 1-(4-Isopropylphenyl)buta-2,3-dien-1-one (3b).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
Interestingly, there was no isomerized product observed after
chromatographic workup on silica gel, this might be due to its steric
hindrance of the protecting group.
10 mol% NaCl
DCE, O2, rt, 5 h
O
2) chromatographic workup
HO
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
on silica gel
3b
1b
TBDMS
91%
1 mmol
TBDMS
Cl
10 mol% NaCl
DCE, O2, rt, 8 h
Cl
O
2o
isolated yield: 65%
HO
1o
2) Chromatographic work-up
on silica gel
The reaction of 1-(4-isopropylphenyl)but-3-yn-1-ol 1b
(187.1 mg, 1.0 mmol), Fe(NO3)3$9H2O (40.6 mg, 0.1 mmol), TEMPO
(15.5 mg, 0.1 mmol), and NaCl (5.8 mg, 0.1 mmol) in DCE (4 mL)
afforded 1-(4-isopropylphenyl)buta-2,3-dien-1-one 3b (167.7 mg,
91%) (eluent: petroleum ether/diethyl ether¼10/1) as an oil.
Scheme 5. Aerobic oxidation of the TBDMS protected-homopropargylic alcohols.
3. Conclusions
1H NMR (300 MHz, CDCl3)
d
7.86 (d, J¼8.1 Hz, 2H, AreH), 7.30 (d,
In summary, we have developed a mild and eco-friendly pro-
tocol for the aerobic oxidation of homopropargylic alcohols using
Fe(NO3)3$9H2O/TEMPO/NaCl as catalysts to synthesize allenic ke-
tones or homopropargylic ketones with moderate to good yields
depending on the nature of substrate (sp-substitution).
J¼8.4 Hz, 2H, AreH), 6.45 (t, J¼6.6 Hz, 1H, HC]C]C), 5.25 (d,
J¼6.6 Hz, 2H, C]C]CH2), 3.20e2.89 (m, 1H, CH), 1.27 (d, J¼6.6 Hz,
6H, CH3); 13C NMR (75.4 MHz, CDCl3)
d 216.8, 190.4, 154.4, 135.2,
128.9, 126.5, 93.1, 79.1, 34.2, 23.6; IR (neat) 2962, 1961, 1933, 1650,
1606, 1568, 1463, 1419, 1350, 1277, 1221, 1186, 1094, 1056 cmꢁ1; MS
(EI) m/z 186 (Mþ, 6.61), 147 (100); HRMS calcd for C13H14O (Mþ):
186.1045; found: 186.1046.
4. Experimental section
4.1. General information
.
1) 10 mol% Fe(NO3)3 9H2O
10 mol% TEMPO
1H and 13C NMR spectra were recorded with an instrument
operated at 300 MHz for 1H NMR and 75 MHz for 13C NMR in CDCl3.
Chemical shifts (d) are given in parts per million (ppm). Infrared
10 mol% NaCl
DCE, O2, rt, 4 h
O
2) chromatographic workup
HO
on silica gel
3b
1b
spectra were recorded on an FTIR spectrometer. Mass spectra were
recorded in EI mode. HRMS spectra were recorded in EI mode. The
starting materials 1aeo were synthesized according to the
literature.9
5 mmol
86%
The reaction of 1-(4-isopropylphenyl)but-3-yn-1-ol 1b
(943.8 mg, 5.0 mmol), Fe(NO3)3$9H2O (202.7 mg, 0.5 mmol),
TEMPO (78.5 mg, 0.5 mmol), and NaCl (28.4 mg, 0.5 mmol) in DCE
(5 mL) afforded 1-(4-isopropylphenyl)buta-2,3-dien-1-one 3b
(800.8 mg, 86%) (eluent: petroleum ether/diethyl ether¼10/1) as an
oil.
4.2. Synthesis of 3aen and 2o
4.2.1. 1-Phenylbuta-2,3-dien-1-one (3a).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
10 mol% NaCl
4.2.3. 1-(Naphth-1-yl)buta-2,3-dien-1-one (3c).
DCE, O2, rt, 4 h
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
HO
O
3a
2) chromatographic workup
on silica gel
1a
1 mmol
87%
10 mol% NaCl
DCE, O2, rt, 24 h
O
HO
2) chromatographic workup
on silica gel
3c
1c
1 mmol
54% (31%)
Typical procedure: To a 10 mL three-necked flask were added
Fe(NO3)3$9H2O (40.2 mg, 0.1 mmol), TEMPO (15.8 mg, 0.1 mmol),
NaCl (6.0 mg, 0.1 mmol), and DCE (4 mL). 1-Phenylbut-3-yn-1-ol 1a
(144.7 mg, 1.0 mmol) was then added to the suspension and the
resulting mixture was placed under the atmosphere of oxygen from
a balloon and stirred at room temperature until the reaction was
complete as monitored by TLC (eluent: petroleum ether/ethyl
The reaction of 1-(naphthalen-1-yl)but-3-yn-1-ol 1c (196.6 mg,
1.0 mmol), Fe(NO3)3$9H2O (41.0 mg, 0.1 mmol), TEMPO (15.5 mg,
0.1 mmol), and NaCl (6.0 mg, 0.1 mmol) in DCE (4 mL) afforded 1-
(naphthalen-1-yl)buta-2,3-dien-1-one11 3c (105.2 mg, 54%) (elu-
ent: petroleum ether/diethyl ether¼10/1) as an oil (31% of the
starting material by NMR analysis).
acetate¼10:1). Mesitylene (46
ml) was added for crude NMR anal-
ysis. The resulting mixture was purified by column chromatography
on silica gel (petroleum ether/diethyl ether¼10/1) to afford 1-
phenylbuta-2,3-dien-1-one10 3a (124.7 mg, 87%) (eluent: petro-
leum ether/diethyl ether¼20/1) as an oil.
1H NMR (300 MHz, CDCl3)
d
8.35 (d, J¼8.4 Hz, 1H, AreH), 7.94 (d,
J¼8.4 Hz, 1H, AreH), 7.90e7.83 (m, 1H, AreH), 7.72 (dd, J1¼7.1 Hz,
J2¼1.1 Hz, 1H, AreH), 7.60e7.42 (m, 3H, AreH), 6.38 (t, J¼6.5 Hz, 1H,
HC]C]C), 5.08 (d, J¼6.3 Hz, 2H, C]C]CH2); 13C NMR (75.4 MHz,
1H NMR (300 MHz, CDCl3)
d 7.93e7.86 (m, 2H, AreH), 7.58e7.52
(m, 1H, AreH), 7.44 (t, J¼7.5 Hz, 2H, AreH), 6.44 (t, J¼6.5 Hz, 1H,
CDCl3) d 217.8, 194.9, 135.6, 133.6, 131.6, 130.2, 128.2, 127.4, 127.3,
HC]C]C), 5.25 (d, J¼6.6 Hz, 2H, C]C]CH2); 13C NMR (75.4 MHz,
126.2, 125.3, 124.0, 97.1, 79.2; IR (neat) 1958, 1932, 1649, 1508, 1282,
CDCl3)
d
217.1, 191.0, 137.4, 132.8, 128.7, 128.3, 93.2, 79.2; IR (neat)
1247, 1191, 1132 cmꢁ1; MS (EI) m/z 194 (Mþ, 28.97), 127 (100).

10164
J. Liu, S. Ma / Tetrahedron 69 (2013) 10161e10167
4.2.4. 1-(4-Methoxyphenyl)buta-2,3-dien-1-one (3d).
4.2.6. 1-(2-Methoxyphenyl)buta-2,3-dien-1-one (3f).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
O
O
10 mol% NaCl
DCE, O2, rt, 5 h
10 mol% NaCl
DCE, O2, rt, 7 h
O
O
HO
1f
1 mmol
HO
O
O
2) chromatographic workup
2) chromatographic workup
on silica gel
on silica gel
3d
3f
1d
81%
80%
1 mmol
The reaction of 1-(2-methoxyphenyl)but-3-yn-1-ol 1f
(174.5 mg, 1.0 mmol), Fe(NO3)3$9H2O (41.0 mg, 0.1 mmol), TEMPO
(15.4 mg, 0.1 mmol), and NaCl (6.0 mg, 0.1 mmol) in DCE (4 mL)
afforded 1-(2-methoxyphenyl)buta-2,3-dien-1-one 3f (137.3 mg,
80%) (eluent: petroleum ether/diethyl ether¼5/1) as an oil.
The reaction of 1-(4-methoxyphenyl)but-3-yn-1-ol 1d
(176.7 mg, 1.0 mmol), Fe(NO3)3$9H2O (40.4 mg, 0.1 mmol), TEMPO
(15.7 mg, 0.1 mmol), and NaCl (5.6 mg, 0.1 mmol) in DCE (4 mL)
afforded 1-(4-methoxyphenyl)buta-2,3-dien-1-one11 3d (142.1 mg,
81%) (eluent: petroleum ether/diethyl ether¼10/1) as a white solid:
mp 54e55 ꢀC (n-hexane/ethyl acetate).
1H NMR (300 MHz, CDCl3)
d
7.50 (dd, J1¼7.7 Hz, J2¼2.0 Hz, 1H,
AreH), 7.44e7.37 (m, 1H, AreH), 7.00e6.90 (m, 2H, AreH), 6.44 (t,
J¼6.3 Hz, 1H, HC]C]C), 5.14 (d, J¼6.6 Hz, 2H, C]C]CH2), 3.85 (s,
1H NMR (300 MHz, CDCl3)
d
7.92 (dt, J1¼9.2 Hz, J2¼2.5 Hz, 2H,
3H, OCH3); 13C NMR (75.4 MHz, CDCl3)
d 216.9, 192.6, 157.6, 132.7,
AreH), 6.93 (dt, J1¼9.4 Hz, J2¼2.4 Hz, 2H, AreH), 6.44 (t, J¼6.6 Hz,
1H, C]C]CH), 5.24 (d, J¼6.6 Hz, 2H, C]C]CH2), 3.86 (s, 3H, CH3);
129.9, 128.4, 120.3, 111.3, 96.6, 78.9, 55.5; IR (neat) 1959, 1934, 1656,
1598, 1486, 1465, 1436, 1339, 1283, 1246, 1163, 1022 cmꢁ1; MS (EI)
m/z 174 (Mþ, 6.55), 135 (100); HRMS calcd for C11H10O2 (Mþ):
174.0681; found: 174.0682.
13C NMR (75.4 MHz, CDCl3)
d 216.5, 189.0, 163.4, 131.0, 130.3, 113.6,
92.8, 79.0, 55.4; IR (neat) 2976, 1957, 1924, 1642, 1591, 1508, 1421,
1351, 1260, 1220, 1170, 1094, 1026 cmꢁ1; MS (EI) m/z 174 (Mþ, 2.82),
63 (100).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
O
O
10 mol% NaCl
DCE, O2, rt, 7 h
10 mol% NaCl
HO
1f
5 mmol
O
DCE, O2, rt, 11 h
O
O
3f
2) chromatographic workup
on silica gel
HO
1d
O
2) chromatographic workup
on silica gel
83%
3d
88%
The reaction of 1-(2-methoxyphenyl)but-3-yn-1-ol 1f
(884.6 mg, 5.0 mmol), Fe(NO3)3$9H2O (202.0 mg, 0.5 mmol),
TEMPO (77.9 mg, 0.5 mmol), and NaCl (29.5 mg, 0.5 mmol) in DCE
(5 mL) afforded 1-(2-methoxyphenyl)buta-2,3-dien-1-one 3f
(722.0 mg, 83%) (eluent: petroleum ether/diethyl ether¼10/1) as an
oil.
5 mmol
The reaction of 1-(4-methoxyphenyl)but-3-yn-1-ol 1d
(881.5 mg, 5.0 mmol), Fe(NO3)3$9H2O (202.0 mg, 0.5 mmol),
TEMPO (78.9 mg, 0.5 mmol), and NaCl (29.2 mg, 0.5 mmol) in DCE
(5 mL) afforded 1-(4-methoxyphenyl)buta-2,3-dien-1-one 3d
(768.1 mg, 88%) (eluent: petroleum ether/diethyl ether¼10/1) as
a white solid.
4.2.7. 1-(2,4,6-Trimethoxyphenyl)buta-2,3-dien-1-one (3g).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
4.2.5. 1-(3-Methoxyphenyl)buta-2,3-dien-1-one (3e).
O
O
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
10 mol% NaCl
DCE, O2, rt, 5 h
O
O
O
O
HO
O
2) chromatographic workup
10 mol% NaCl
DCE, O2, rt, 6 h
on silica gel
O
O
86%
1g
1 mmol
3g
HO
1e
2) chromatographic workup
O
on silica gel
3e
1 mmol
89%
The reaction of 1-(2,4,6-trimethoxyphenyl)but-3-yn-1-ol 1g
(236.0 mg, 1.0 mmol), Fe(NO3)3$9H2O (39.4 mg, 0.1 mmol), TEMPO
(15.5 mg, 0.1 mmol), and NaCl (5.8 mg, 0.1 mmol) in DCE (4 mL)
afforded 1-(2,4,6-trimethoxyphenyl)buta-2,3-dien-1-one11 3g
(200.9 mg, 86%) (eluent: petroleum ether/diethyl ether¼1/1) as
a yellow solid: mp 73e74 ꢀC (n-hexane/ethyl acetate).
The reaction of 1-(3-methoxyphenyl)but-3-yn-1-ol 1e
(174.8 mg, 1.0 mmol), Fe(NO3)3$9H2O (40.6 mg, 0.1 mmol), TEMPO
(15.4 mg, 0.1 mmol), and NaCl (6.0 mg, 0.1 mmol) in DCE (4 mL)
afforded 1-(3-methoxyphenyl)buta-2,3-dien-1-one5b 3e (153.1 mg,
89%) (petroleum ether/diethyl ether¼10/1) as an oil.
1H NMR (300 MHz, CDCl3)
1H, HC]C]C), 5.26 (d, J¼6.3 Hz, 2H, C]C]CH2), 3.911 (s, 3H),
3.909 (s, 3H), 3.90 (s, 3H); 13C NMR (75.4 MHz, CDCl3)
216.6, 189.5,
d
7.19 (s, 2H, AreH), 6.42 (t, J¼6.5 Hz,
1H NMR (300 MHz, CDCl3)
d
7.47 (d, J¼7.8 Hz, 1H, AreH), 7.41 (t,
J¼2.0 Hz,1H, AreH), 7.34 (t, J¼7.8 Hz,1H, AreH), 7.09 (dd, J1¼8.1 Hz,
J2¼2.4 Hz, 1H, AreH), 6.43 (t, J¼6.6 Hz, 1H, HC]C]C), 5.25 (d,
J¼6.9 Hz, 2H, C]C]CH2), 3.83 (s, 3H, OCH3); 13C NMR (75.4 MHz,
d
152.9, 142.5, 132.5, 106.3, 93.0, 79.0, 60.9, 56.2; IR (neat) 1939, 1648,
1583,1504,1451,1412,1337,1313,1244,1226,1185,1155,1125 cmꢁ1
;
CDCl3)
d 217.0, 190.6, 159.6, 138.7, 129.3, 121.2, 119.2, 113.0, 93.2,
MS (EI) m/z 234 (Mþ, 47.68), 195 (100).
79.2, 55.3; IR (neat) 1959, 1933, 1654, 1595, 1581, 1486, 1452, 1429,
1286, 1259, 1037 cmꢁ1; MS (EI) m/z 174 (Mþ, 51.12), 135 (100).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
O
O
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
10 mol% NaCl
DCE, O2, rt, 5 h
O
O
O
O
10 mol% NaCl
DCE, O2, rt, 6 h
HO
O
2) chromatographic workup
on silica gel
O
O
HO
1e
2) chromatographic workup
O
84%
1g
5 mmol
3g
on silica gel
3e
5 mmol
85%
The reaction of 1-(2,4,6-trimethoxyphenyl)but-3-yn-1-ol 1g
(1.1825 g, 5.0 mmol), Fe(NO3)3$9H2O (200.4 mg, 0.5 mmol), TEMPO
(77.7 mg, 0.5 mmol), and NaCl (29.6 mg, 0.5 mmol) in DCE (5 mL)
The reaction of 1-(3-methoxyphenyl)but-3-yn-1-ol 1e
(834.1 mg, 5.0 mmol), Fe(NO3)3$9H2O (201.5 mg, 0.5 mmol), TEMPO
(77.6 mg, 0.5 mmol), and NaCl (28.5 mg, 0.5 mmol) in DCE (5 mL)
afforded 1-(3-methoxyphenyl)buta-2,3-dien-1-one 3e (703.3 mg,
85%) (eluent: petroleum ether/diethyl ether¼10/1) as an oil.
afforded
1-(2,4,6-trimethoxyphenyl)buta-2,3-dien-1-one
3g
(989.9 mg, 84%) (eluent: petroleum ether/diethyl ether¼1/1) as
a yellow solid.

J. Liu, S. Ma / Tetrahedron 69 (2013) 10161e10167
10165
4.2.8. 1-(4-Bromophenyl)buta-2,3-dien-1-one (3h).
4.2.10. 1-(4-Chlorophenyl)buta-2,3-dien-1-one (3j).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
10 mol% NaCl
DCE, O2, rt, 24 h
10 mol% NaCl
DCE, O2, rt, 24 h
Cl
Cl
Br
Br
HO
O
2) chromatographic workup
HO
1h
O
3h
2) chromatographic workup
1j
on silica gel
on silica gel
3j
1 mmol
1 mmol
83%
77%
The reaction of 1-(4-chlorophenyl)but-3-yn-1-ol 1j (179.8 mg,
1.0 mmol), Fe(NO3)3$9H2O (39.8 mg, 0.1 mmol), TEMPO (15.7 mg,
0.1 mmol), and NaCl (5.6 mg, 0.1 mmol) in DCE (4 mL) afforded 1-
(4-chlorophenyl)buta-2,3-dien-1-one 3j (147.0 mg, 83%) (eluent:
petroleum ether/diethyl ether¼10/1) as an oil.
The reaction of 1-(4-bromophenyl)but-3-yn-1-ol 1h (225.3 mg,
1.0 mmol), Fe(NO3)3$9H2O (40.7 mg, 0.1 mmol), TEMPO (15.9 mg,
0.1 mmol), and NaCl (6.0 mg, 0.1 mmol) in DCE (4 mL) afforded 1-
(4-bromophenyl)buta-2,3-dien-1-one6 3h (172.8 mg, 77%) (eluent:
petroleum ether/diethyl ether¼10/1) as an oil.
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
1H NMR (300 MHz, CDCl3)
d
7.75 (dt, J1¼8.9 Hz, J2¼2.1 Hz, 2H,
AreH), 7.58 (dt, J1¼8.9 Hz, J2¼2.1 Hz, 2H, AreH), 6.38 (t, J¼6.6 Hz,
10 mol% NaCl
1H, HC]C]C), 5.26 (d, J¼6.3 Hz, 2H, C]C]CH2); 13C NMR
Cl
DCE, O2, rt, 24 h
Cl
HO
1j
O
3j
2) chromatographic workup
(75.4 MHz, CDCl3) d 217.2, 190.0, 136.1, 131.6, 130.2, 127.8, 93.2, 79.5;
on silica gel
IR (neat) 1960, 1931, 1652, 1585, 1566, 1484, 1417, 1395, 1346, 1276,
1211, 1177, 1069, 1009 cmꢁ1; MS (EI) m/z 224 (Mþ(81Br), 0.72), 222
(Mþ(79Br), 1.32), 50 (100).
5 mmol
76%
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
The reaction of 1-(4-chlorophenyl)but-3-yn-1-ol 1j (901.9 mg,
5.0 mmol), Fe(NO3)3$9H2O (202.0 mg, 0.5 mmol), TEMPO (79.0 mg,
0.5 mmol), and NaCl (29.6 mg, 0.5 mmol) in DCE (5 mL) afforded 1-
(4-chlorophenyl)buta-2,3-dien-1-one8a 3j (674.8 mg, 76%) as an oil.
10 mol% NaCl
DCE, O2, rt, 24 h
Br
Br
HO
1h
5 mmol
O
2) chromatographic workup
on silica gel
1H NMR (300 MHz, CDCl3)
d
7.83 (dt, J1¼8.9 Hz, J2¼2.1 Hz, 2H,
3h
71%
AreH), 7.41 (dt, J1¼8.7 Hz, J2¼2.3 Hz, 2H, AreH), 6.38 (t, J¼6.5 Hz,
The reaction of 1-(4-bromophenyl)but-3-yn-1-ol 1h (1.1338 g,
5.0 mmol), Fe(NO3)3$9H2O (199.2 mg, 0.5 mmol), TEMPO (78.5 mg,
0.5 mmol), and NaCl (28.9 mg, 0.5 mmol) in DCE (5 mL) afforded 1-
(4-bromophenyl)buta-2,3-dien-1-one 3h (797.0 mg, 71%) (eluent:
petroleum ether/diethyl ether¼10/1) as an oil.
1H, HC]C]C), 5.26 (d, J¼6.6 Hz, 2H, C]C]CH2); 13C NMR
(75.4 MHz, CDCl3) d 217.1, 189.8, 139.1, 135.6, 130.1, 128.6, 93.2, 79.4.
4.2.11. 1-(2-Thienyl)buta-2,3-dien-1-one (3k).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
4.2.9. 1-(4-Ethylphenyl)buta-2,3-dien-1-one (3i).
10 mol% NaCl
S
S
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
DCE, O2, rt, 3 h
2) chromatographic workup
HO
1k
1 mmol
O
3k
on silica gel
10 mol% NaCl
DCE, O2, rt, 7.5 h
91%
HO
1i
O
2) chromatographic workup
on silica gel
3i
1 mmol
85%
The reaction of 1-(2-thienyl)but-3-yn-1-ol 1k (151.6 mg,
1.0 mmol), Fe(NO3)3$9H2O (40.7 mg, 0.1 mmol), TEMPO (15.9 mg,
0.1 mmol), and NaCl (5.8 mg, 0.1 mmol) in DCE (4 mL) afforded 1-
(2-thienyl)buta-2,3-dien-1-one 3k (136.0 mg, 91%) (eluent: petro-
leum ether/diethyl ether¼10/1) as an oil.
The reaction of 1-(4-ethylphenyl)but-3-yn-1-ol 1i (174.0 mg,
1.0 mmol), Fe(NO3)3$9H2O (40.0 mg, 0.1 mmol), TEMPO (15.8 mg,
0.1 mmol), and NaCl (5.8 mg, 0.1 mmol) in DCE (4 mL) afforded 1-
(4-ethylphenyl)buta-2,3-dien-1-one 3i (145.8 mg, 85%) (eluent:
petroleum ether/diethyl ether¼10/1) as an oil.
1H NMR (300 MHz, CDCl3)
d
7.84 (d, J¼6.6 Hz, 2H, AreH), 7.26 (d,
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
J¼8.4 Hz, 2H, AreH), 6.44 (t, J¼6.5 Hz, 1H, HC]C]C), 5.24 (d,
J¼6.6 Hz, 2H, C]C]CH2), 2.69 (q, J¼7.6 Hz, 2H, CH2), 1.25 (t,
10 mol% NaCl
DCE, O2, rt, 3 h
S
S
J¼7.5 Hz, 3H, CH3); 13C NMR (75.4 MHz, CDCl3)
d 216.7, 190.3, 149.7,
2) chromatographic workup
HO
1k
O
3k
135.0, 128.8, 127.8, 93.0, 79.0, 28.8, 15.0; IR (neat) 2970, 2878, 2831,
1961, 1933, 1650, 1606, 1578, 1508, 1417, 1347, 1276, 1220,
1181 cmꢁ1; MS (EI) m/z 172 (Mþ, 2.14), 133 (100); HRMS calcd for
on silica gel
89%
5 mmol
C
12H12O (Mþ): 172.0888; found: 172.0889.
The reaction of 1-(2-thienyl)but-3-yn-1-ol 1k (759.6 mg,
5.0 mmol), Fe(NO3)3$9H2O (204.9 mg, 0.5 mmol), TEMPO (77.2 mg,
0.5 mmol), and NaCl (28.8 mg, 0.5 mmol) in DCE (5 mL) afforded 1-
(2-thienyl)buta-2,3-dien-1-one 3k (664.5 mg, 89%) (eluent: pe-
troleum ether/diethyl ether¼10/1) as an oil.
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
10 mol% NaCl
DCE, O2, rt, 10 h
HO
1i
5 mmol
O
2) chromatographic workup
on silica gel
1H NMR (300 MHz, CDCl3)
d
7.82 (d, J¼3.6 Hz, 1H, heteroaryl-H),
3i
84%
7.63 (d, J¼4.8 Hz, 1H, heteroaryl-H), 7.11 (t, J¼4.4 Hz,1H, heteroaryl-
H), 6.37 (t, J¼6.6 Hz, 1H, HC]C]C), 5.33 (d, J¼6.6 Hz, 2H, C]C]
The reaction of 1-(4-ethylphenyl)but-3-yn-1-ol 1i (869.1 mg,
5.0 mmol), Fe(NO3)3$9H2O (203.1 mg, 0.5 mmol), TEMPO (77.0 mg,
0.5 mmol), and NaCl (28.2 mg, 0.5 mmol) in DCE (5 mL) afforded 1-
(4-ethylphenyl)buta-2,3-dien-1-one 3i (724.0 mg, 84%) (eluent:
petroleum ether/diethyl ether¼10/1) as an oil.
CH2); 13C NMR (75.4 MHz, CDCl3)
d 215.8, 181.8, 143.5, 133.7, 132.4,
127.8, 93.2, 79.8; IR (neat) 1961, 1933, 1630, 1516, 1412, 1357, 1279,
1236, 1219 cmꢁ1; MS (EI) m/z 150 (Mþ, 20.34), 111 (100); HRMS
calcd for C8H6O4S (Mþ): 150.0139; found: 150.0138.

10166
J. Liu, S. Ma / Tetrahedron 69 (2013) 10161e10167
4.2.12. 1-(2-Furyl)buta-2,3-dien-1-one (3l).
4.2.14. Trideca-1,2-dien-4-one (3n).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
10 mol% NaCl
O
10 mol% NaCl
DCE, O2, rt, 48 h
O
DCE, O2, rt, 5 h
C9H19-n
C9H19-n
2) chromatographic workup
HO
1l
O
HO
1n
2) chromatographic workup
O
3n
on silica gel
on silica gel
3l
81%
1 mmol
1 mmol
51% (44%)
The reaction of tridec-1-yn-4-ol 1n (196.1 mg, 1.0 mmol),
Fe(NO3)3$9H2O (41.0 mg, 0.05 mmol), TEMPO (15.6 mg, 0.05 mmol),
and NaCl (6.0 mg, 0.05 mmol) in DCE (4 mL) afforded trideca-1,2-
dien-4-one8a 3n (98.3 mg, 51%) (eluent: petroleum ether/diethyl
ether¼10/1) as an oil (44% of the starting material by NMR
analysis).
The reaction of 1-(2-furyl)but-3-yn-1-ol 1l (135.4 mg,
1.0 mmol), Fe(NO3)3$9H2O (40.3 mg, 0.1 mmol), TEMPO (15.9 mg,
0.1 mmol), and NaCl (5.5 mg, 0.1 mmol) in DCE (4 mL) afforded 1-
(2-furyl)buta-2,3-dien-1-one 3l (107.4 mg, 81%) (eluent: petroleum
ether/diethyl ether¼10/1) as an oil.
1H NMR (300 MHz, CDCl3)
d
5.76 (t, J¼6.6 Hz, 1H, HC]C]C),
5.22 (d, J¼6.3 Hz, 2H, C]C]CH2), 2.59 (t, J¼7.5 Hz, 2H, CH2),
The reaction of 1-(2-furyl)but-3-yn-1-ol 1l (681.3 mg,
5.0 mmol), Fe(NO3)3$9H2O (204.0 mg, 0.5 mmol), TEMPO (78.7 mg,
0.5 mmol), and NaCl (28.8 mg, 0.5 mmol) in DCE (5 mL) afforded 1-
(2-furyl)buta-2,3-dien-1-one11 3l (516.2 mg, 77%) (eluent: petro-
leum ether/diethyl ether¼10/1) as an oil.
1.62e1.50 (m, 2H, CH2), 1.35e1.08 (m, 12H, CH2), 0.87 (t, J¼6.8 Hz,
3H, CH3); 13C NMR (75.4 MHz, CDCl3)
d 216.6, 201.0, 96.7, 79.2, 39.2,
31.8, 29.4, 29.3, 29.22, 29.17, 24.6, 22.6, 14.1.
4.2.15. 4-(tert-Butyldimethylsilyl)-1-(4-chlorophenyl)but-3-yn-1-
one (2o).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
10 mol% NaCl
DCE, O2, rt, 8 h
10 mol% NaCl
DCE, O2, rt, 5 h
TBDMS
TBDMS
O
O
Cl
Cl
2) chromatographic workup
O
HO
2) chromatographic workup
HO
1l
O
on silica gel
2o
on silica gel
1o
1 mmol
3l
65%
5 mmol
77%
The reaction of 4-(tert-butyldimethylsilyl)-1-(4-chlorophenyl)
but-3-yn-1-ol 1o (293.1 mg, 1.0 mmol), Fe(NO3)3$9H2O (40.5 mg,
0.1 mmol), TEMPO (15.7 mg, 0.1 mmol), and NaCl (6.0 mg,
0.1 mmol) in DCE (4 mL) afforded 4-(tert-butyldimethylsilyl)-1-(4-
chlorophenyl)but-3-yn-1-one 2o (187.9 mg, 65%) (eluent: petro-
leum ether/diethyl ether¼10/1) as an oil.
1H NMR (300 MHz, CDCl3)
d
7.60 (dd, J1¼1.5 Hz, J2¼0.8 Hz, 1H,
heteroaryl-H), 7.28 (dd, J1¼3.6 Hz, J2¼0.6 Hz,1H, heteroaryl-H), 6.54
(dd, J1¼3.6 Hz, J2¼1.8 Hz, 1H, heteroaryl-H), 6.44 (t, J¼6.5 Hz, 1H,
HC]C]C), 5.34 (d, J¼6.6 Hz, 2H, C]C]CH2); 13C NMR (75.4 MHz,
1H NMR (300 MHz, CDCl3)
d
7.97 (dt, J1¼8.8 Hz, J2¼2.1 Hz, 2H,
CDCl3)
d 216.1, 177.7, 152.3, 146.5, 118.0, 112.3, 92.4, 79.7; IR (neat)
1960,1933,1645,1567,1465,1418,1392,1164,1016 cmꢁ1; MS (EI) m/
z 134 (Mþ, 19.84), 95 (100).
AreH), 7.44 (dt, J1¼8.9 Hz, J2¼2.3 Hz, 2H, AreH), 3.83 (s, 2H, CH2),
0.88 (s, 9H, C(CH3)3), 0.07 (s, 6H, CH3); 13C NMR (75.4 MHz, CDCl3)
d
191.8, 139.9, 133.5, 130.2, 128.8, 98.5, 89.2, 32.1, 25.9, 16.5, ꢁ4.8; IR
(neat) 2178, 1694, 1590, 1489, 1471, 1400, 1208, 1093, 1010 cmꢁ1; MS
(EI) m/z 294 (Mþ(37Cl), 0.15), 292 (Mþ(35Cl), 0.44), 111 (100); HRMS
calcd for C16H21OSi35Cl (Mþ): 292.1050; found: 292.1053.
4.2.13. 1-Cyclohexylbuta-2,3-dien-1-one (3m).
1) 10 mol% Fe(NO3)3.9H2O
10 mol% TEMPO
Acknowledgements
10 mol% NaCl
DCE, O2, rt, 48 h
O
HO
1m
2) chromatographic workup
We greatly acknowledge the financial support from the National
Basic Research Program of China (no. 2009CB825300) and the
National Natural Science Foundation of China of China (21232006).
We thank Shangze Wu in our group for reproducing the results of
compound 3b and 3m presented in this study.
3m
on silica gel
1 mmol
39% (40%)
Supplementary data
The reaction of 1-cyclohexylbut-3-yn-1-ol 1m (152.9 mg,
1.0 mmol), Fe(NO3)3$9H2O (40.9 mg, 0.1 mmol), TEMPO (15.5 mg,
0.1 mmol), and NaCl (5.4 mg, 0.1 mmol) in DCE (4 mL) afforded 1-
cyclohexylbuta-2,3-dien-1-one10 3m (59.3 mg, 39%) as an oil (40%
of the starting material by NMR analysis).
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.tet.2013.08.082.
References and notes
1H NMR (300 MHz, CDCl3)
d
5.74 (t, J¼6.6 Hz, 1H, HC]C]C),
5.22 (d, J¼6.6 Hz, 2H, C]C]CH2), 2.80e2.49 (m, 1H, CH), 1.82e1.60
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J. Liu, S. Ma / Tetrahedron 69 (2013) 10161e10167
10167
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