Iron-catalyzed synthesis of β-chlorovinyl and α,β-alkynyl ketones from terminal and silylated alkynes with acid chlorides

Article abstract of DOI:10.1002/adsc.201100670

A simple efficient method for the iron(III)-catalyzed synthesis of substituted β-chlorovinyl ketones and α,β-alkynyl ketones from terminal and silyl-substituted alkynes with acid chlorides, respectively, is described. This method features easily available

Full text of DOI:10.1002/adsc.201100670

FULL PAPERS
DOI: 10.1002/adsc.201100670
Iron-Catalyzed Synthesis of b-Chlorovinyl and a,b-Alkynyl
Ketones from Terminal and Silylated Alkynes with Acid
Chlorides
Parthasarathy Gandeepan,a Kanniyappan Parthasarathy,a Tsu-Hui Su,a
and Chien-Hong Chenga,*
a
Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
E-mail: chcheng@mx.nthu.edu.tw
Received: August 24, 2011; Revised: October 14, 2011; Published online: February 9, 2012
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/adsc.201100670.
Abstract: A simple efficient method for the iron- the acid chloride to a terminal alkyne to give (Z)-b-
ACHTUNGTRENNUNG(III)-catalyzed synthesis of substituted b-chlorovinyl chlorovinyl ketones favours a concerted pathway via
ketones and a,b-alkynyl ketones from terminal and a four-membered ring transition state between the
silyl-substituted alkynes with acid chlorides, respec- two alkyne carbons and the carbon-chloride bond of
tively, is described. This method features easily avail- the acid chloride.
able starting materials, a cheap and non-toxic cata-
lyst, simple manipulation and mild reaction condi- Keywords: acid chlorides; alkynes; a,b-alkynyl ke-
tions. Evidence shows that the catalytic addition of tones; b-chlorovinyl ketones; iron
Introduction
workers reported a GaCl3-catalyzed synthesis of b-
chloroalkenyl ketones from terminal alkynes and acid
b-Chloroalkenyl ketones are valuable and versatile chlorides.[5] However this reaction proceeds with
synthetic intermediates for the synthesis of various lower stereoselectivity. Recently, Wang et al. showed
novel heterocyclic compounds.[1] Traditional ap- an FeBr2-catalyzed synthesis of b-chloroalkenyl ke-
proaches to these compounds involved Friedel–Crafts tones by the addition of acid chlorides to terminal
addition of acid chlorides to alkynes in the presence alkynes at high temperature (1108C).[6a] Later, Sarvari
of stoichiometric amounts of Lewis acids.[2] Recently, and Mardanesh demonstrated a ZnO-catalyzed for-
metal-catalyzed addition of acid chlorides to alkynes mation of b-chloroalkenyl ketones under solvent-free
has become a prevailing method for the synthesis of conditions.[6b] The methods described above for syn-
substituted b-chloroalkenyl ketones. In this context, thesizing b-chloroalkenyl ketones generally required a
Tanaka et el. reported a series of rhodium-catalyzed long reaction time, an expensive catalyst or relatively
addition reactions of chloroformate esters,[3a] per- harsh reaction conditions. In addition, several re-
fluorinated acid chlorides,[3b]ethyl chloroglyoxylate,[3c] search groups have reported facile decarbonylative
chloroacetyl chlorides,[3d] and a-keto acid chlorides[3e] additions of acid chlorides to terminal alkynes[7a] and
to terminal alkynes. Recently, Tsuji and co-workers alkenes.[7b] Our continued interest in metal-catalyzed
described an IrCl
ACHTUNGTRENNUNG(cod)ACHTUGNTRENNNUG
matic acid chlorides to terminal alkynes to form b-
AHCTUNGTRENNUNG
chloro-a,b-unsaturated ketones.[4] These rhodium- and using low-cost and non-toxic iron complexes as cata-
iridium-catalyzed b-chloroacylations of alkynes are lysts for the addition reactions. Herein, we wish to
generally considered to proceed via oxidative addition report a convenient FeCl3-catalyzed regio- and stereo-
of acyl chloride to metal complexes followed by addi- selective synthesis of substituted b-chloroalkenyl ke-
tion to the alkyne. Another type of b-chloroacylation tones from acid chlorides and terminal alkynes under
of alkynes is the Lewis acid-catalyzed addition of acyl mild reaction conditions.
chloride to alkyne. Apart from the earlier Lewis acid-
catalyzed addition pathway,[2] in 2006, Zhou and co-
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Table 1. Results of the reaction of acid chlorides with termi-
Results and Discussion
nal alkynes.[a]
Treatment of 4-methoxybenzoyl chloride (1a) with
phenylacetylene (2a) in the presence of 10 mol%
FeCl3 in CHCl3 at 08C for 15 h gave the substituted b-
chloroalkenyl ketone 3a in 90% isolated yield with
excellent regio- and stereoselectivity (Z/E>99/1)
(Table 1, entry 1). Product 3a was thoroughly charac-
1
terized by its H NMR, 13C NMR and mass spectro-
scopic data.
To evaluate the effect of the catalyst on the b-
chloroACHTUNGTRENNUNGalkenyl ketone formation reaction, various iron
salts were used for the reaction of 1a with 2a in
CHCl3. Among those iron salts used, FeCl3 gave the
best results and afforded 3a in 90% yield. Other iron
salts including FeCl3·6H2O, Fe
N
ACHTUNGTRNE(NUNG ClO4)3,
FeSO4·7H2O, FeBr2, FeCl2, and Fe
AHCTUNGTRENNUNG
Entry
1
1
2
Product 3
Yield [%][b] (Z/E)[c]
90 (>99/1)
fective giving 3a in 23, 36, 17, 12, 15, 20 and 8%
yields, respectively. The solvent employed is also vital
to the catalytic reaction. The best solvent is CHCl3 in
which 3a was obtained in 90% yield. 1,2-Dichloro-
ethane is also effective giving 3a in 53% yield. Other
solvents including dichloromethane, toluene, CH3CN,
THF and benzene are less effective for the catalytic
reaction (see the Supporting Information for details).
It is important to mention that control experiments
showed that in the absence of an iron salt, no desired
product 3a was obtained.
1a 2a
1b 2a
1c 2a
1d 2a
1e 2a
1f 2a
2
3
4
5
6
81 (98/2)
68 (98/2)
74 (98/2)
84 (99/1)
74 (99/1)
Under similar reaction conditions, various substitut-
ed acid chlorides (1b–k) reacted smoothly with phe-
nylacetylene (2a) to give the corresponding b-chloro-
ACHTUNGTRENNUNGalkenyl ketones. Benzoyl chloride 1b underwent the
chloroacylation reaction effectively with 2a, affording
b-chloroalkenyl ketone derivative 3b in 81% yield
(Table 1, entry 2). Notably, all ortho-, meta-, and para-
methylbenzoyl chlorides 1c, 1d and 1e could be
smoothly transformed in to desired products 3c, 3d
and 3e in 68, 74 and 84% yields, respectively (en-
tries 3–5). In a similar manner, 2-fluoro-, 4-fluoro-
and 4-bromobenzoyl chlorides 1f, 1g and 1h gave
chlorovinyl ketone derivatives 3f, 3g and 3h in 74, 68
and 81% yields, respectively (entries 6–8). The scope
of the catalytic reaction can further be extended to a
heterocyclic acid chloride. Thus, thiophene-2-carbonyl
chloride (1i) reacted with 2a to give 3i in 83% yield
(entry 9). Aliphatic acid chlorides also worked well
for this reaction. Thus, pentanoyl chloride (1j) and
isobutyryl chloride (1k) reacted nicely with 2a to give
3j and 3k in 79 and 85% yields, respectively (en-
tries 10 and 11).
7
1g 2a
68 (99/1)
8
1h 2a
1i 2a
1j 2a
1k 2a
81 (99/1)
83 (99/1)
79 (97/3)
85 (98/2)
9
10
11
The present iron-catalyzed chloroacylation reaction
can also apply to various terminal alkynes 2b–h. Thus,
the reactions of 2-methyl-, 3-methyl-, 4-methyl- and 4-
chlorophenylacetylene 2b–e with 1b gave b-chloroal-
kenyl ketones 3l–o in 70, 76, 71 and 83% yields, re-
spectively (Table 1, entries 12–15). In
a similar
manner, 1-pentyne (2f) and 1-decyne (2g) reacted
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Iron-Catalyzed Synthesis of b-Chlorovinyl and a,b-Alkynyl Ketones from Terminal and Silylated Alkynes
well with 1b to provide the expected b-chloroalkenyl
ketone derivative 3r in 76% yield (entry 18).
Table 1. (Continued)
Entry
1
2
Product 3
Yield [%][b] (Z/E)[c]
The catalytic chloroacylation reaction was success-
fully extended to internal alkynes with various acid
chlorides (Scheme 1). Thus, treatment of hex-3-yne
with 4-methoxybenzoyl chloride (1a) gave the corre-
sponding b-chloroalkenyl ketone 4a in 89% yield with
excellent regio- and stereoselectivity. In contrast to
the observed stereochemistry of the chloroacylation
of terminal alkynes, the acyl and the chloro groups in
product 4a are trans to each other with an E/Z ratio
>99/1. Other acid chlorides 1b, 1g, 1h and 1i also re-
acted efficiently with hex-3-yne to give the corre-
sponding addition products 4b–e in good to excellent
yields, but with lower stereoselectivity (Scheme 1).
The major species in these reactions are also E iso-
mers. In a similar manner, symmetrically substituted
octa-4-yne reacted smoothly with acid chlorides 1a,
lb, 1g, 1h and 1i under similar reaction conditions to
provide chloroacylation products 3s–w in good to ex-
cellent yields with similar E/Z ratios as those of prod-
ucts 4f–j. It is noteworthy that diphenylacetylene
does not react with acid chloride 1a to give the ex-
pected chloroacylation product. The reaction is likely
prohibited by the large steric repulsion arising from
the two phenyl, acyl and chloro groups during the for-
mation of the expected product.
12
1b 2b
1b 2c
1b 2d
1b 2e
70 (97/3)
13
14
76 (99/1)
71 (99/1)
83 (99/1)
15
16
17
1b 2f
1b 2g
1b 2h
82 (99/1)
76 (97/3)
76 (99/1)
18
[a]
Unless otherwise mentioned, all reactions were carried
out with acid chloride 1 (1.0 mmol), alkyne 2 (1.5 mmol),
FeCl3 (10 mol%) and CHCl3 (2.0 mL) at 08C for 15 h
under N2.
Isolated yields.
Determined by H NMR spectroscopy.
The reaction of acyl chlorides with alkynylsilanes
catalyzed by FeCl3 was also investigated. Surprisingly,
the reaction of acid chloride (1a) with 1-phenyl-2-(tri-
methylsilyl)acetylene (2k) under reaction conditions
similar to those shown in Table 1 gave 3a in 24%
yield along with a,b-alkynyl ketone 5a in 67%
(Table 2, entry 1). To improve the yield of 5a, various
[b]
[c]
1
with 1b to afford products 3p and 3q in 82 and 76% solvents were tried (see the Supporting Information
yields, respectively (entries 16 and 17). Sterically for details). The use of CH3NO2 gave 5a in 78% yield
more demanded tert-butylacetylene (2h) also reacted along with 3a in 9% yield. Finally when temperature
Scheme 1. Proposed mechanism for the addition of acid chlorides to terminal alkynes.
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Table 2. Chloroacylation of various acid chlorides with 3-hexyne and 4-octyne.
Entry
1
1
2
Product 4: yield [%][b]
Product 4’: yield [%][b]
1a
2i
2
3
1b
1g
2i
2i
4
5
6
1h
1i
2i
2i
2j
1a
7
8
9
1b
2j
1g
1h
1i
2j
2j
2j
10
[a]
Unless otherwise mentioned, all reactions were carried out with acid chloride 1 (1.0 mmol), alkyne 2 (1.5 mmol), FeCl3
(10 mol%) and CHCl3 (2.0 mL) at 08C for 15 h under N2.
Isolated yields.
[b]
was reduced to À158C from 08C the reaction gave 5a contained in several biologically active molecules[9a]
exclusively in 89% yield as determined by an NMR and play a crucial role as key intermediates in the
integration method (Table 2, entry 8) or 80% isolated synthesis of natural products[9b–e] and heterocyclic
yield. It is interesting to note that alkynyl ketones are compounds.[9f–o] Various methods for the synthesis of
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Iron-Catalyzed Synthesis of b-Chlorovinyl and a,b-Alkynyl Ketones from Terminal and Silylated Alkynes
Table 3. Results on the formation of conjugated ynones.[a]
alkynyl ketones were reported including an equimolar
AlCl3-mediated reaction of alkynylsilanes with acid
chlorides in CS2,[10] alkynones have been typically syn-
thesised by transition metal-catalyzed cross-coupling
reactions of acid chlorides and terminal alkynes.[11]
Alternatively, the cross-couplings of acid chlorides
with the corresponding organometallic reagents and
carbonylative coupling reactions have attracted much
attention.[12] To the best of our knowledge, there is no
known example using low-cost transition metal com-
plexes as catalyst for the coupling of acid chlorides
with alkynylsilanes under very mild conditions.
To probe the generality of the formation of alkynyl
ketone, we investigated the reaction of different acid
chlorides with alkynylsilanes. The conditions for the
synthesis of 5a using FeCl3 (10 mol%) in CH3NO2 at
À158C for 6 h were chosen as the standard conditions
for these catalytic reactions. As revealed in Table 3,
the variety of acid chlorides reacted smoothly with 1-
phenyl-2-(trimethylsilyl)acetylene (2k) to give the cor-
responding a,b-alkynyl ketones. Thus, benzoyl 1b,
ortho-, meta-, para-methylbenzoyl chlorides 1c, 1d
and 1e underwent reaction with 2k to afford the cor-
responding products 5b, 5c, 5d and 5e in 84, 72, 79
and 81% yields, respectively (Table 3, entries 2–5). 2-
Fluoro-, 4-fluoro-, 4-bromo-, and 4-chlorobenzoyl
chlorides 1f, 1g, 1h and 1l provided 5f, 5g, 5h and 5i
on reaction with 2k in 77, 81,79 and 76% yields, re-
spectively (entries 6–9). Under similar reaction condi-
tion, ortho-, meta-, para-tolyl(trimethylsilyl)acetylenes
2l, 2m and 2n reacted with 1b to to produce 5j, 5k
and 5l in 66, 71 and 78% yields, respectively (en-
tries 10–12). Similarly, thiophene-2-carbonyl chloride
(1i) gave 5n in 78% yield (entry 14). Aliphatic acid
chloride 1j is also compatible with the present reac-
tion (entry 15) affording product 5o in 63% yield. The
present catalytic reaction was also successfully ex-
tended to aliphatic alkynes 2p and q. Thus, 1-(trime-
thylsilyl)-2-tert-butylacetylene 2p reacted well with 1b
and 1g to give conjugated ynones 5p and 5q in 93 and
76% yields, respectively (entries 16 and 17). In a simi-
lar manner, the reaction of 1-(trimethylsilyl)propyne
(2q) with 1b gave 5r in 46% yield (entry 18). In addi-
tion, sterically bulkier 1-naphthoyl chloride 1m also
reacted smoothly with 2k to give the conjugated
ynone 5s in good yield (entry 19).
Entry
1
1
2
Product 5
Yield [%][b]
80
1a
2k
2
3
1b
1c
2k
2k
84
72
4
5
6
7
8
9
1d
1e
1f
1g
1h
1l
2k
2k
2k
2k
2k
2k
79
81
77
81
79
76
The observed different stereochemistry for the ad-
dition of acid chloride to terminal and internal al-
kynes is intriguing. The major products from the Frie-
del–Crafts addition of acid chlorides to alkyne which
requires equimolar amounts of acid chloride-AlCl3
complex, have the chlorine and the carbonyl groups
configured in a trans relationship. As well, the GaCl3-
catalyzed reaction also proceeded with lower stereo-
selectivity.[2,5,13] Although the true mechanism is not
yet known, we propose the following schemes to ac-
count for this FeCl3-catalyzed chloroacylation chemis-
10
1b
2l
66
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ble due to the strong steric effect between the aro-
matic substituents of the two substrates.
Table 3. (Continued)
Entry
1
2
Product 5
Yield [%][b]
71
For the reaction of the acid chloride with an inter-
nal alkyne, the formation of a four-membered ring
transition state like A or A’ is less likely due the
steric repulsion between the substituents on the two
substrates. The reaction probably proceeds via the ad-
dition of internal alkyne to the acid chloride-FeCl3
complex followed by chloride elimination to give a al-
kenylÀcation C (Scheme 2).[14a] Attack of cation C by
FeCl4 at the cationic carbon leads to the formation
of both E- and Z-products.[14b–e] It is noteworthy that
the alkenyl cation is expected to have a linear struc-
ture based on theoretical calculations performed by
us. Moreover, this mechanism also accounts for the
formation of a,b-alkynyl ketones 5.
11
1b
2m
12
13
1b
1b
2n
2o
78
80
For the FeCl3-catalyzed reaction of acid chlorides
with alkynylsilanes, the formation of alkenyl cation C’
is also expected. Additional stabilization of this cation
by the trimethylsilyl group likely occurs that leads to
14
15
1i
1j
2k
2k
78
63
À
the attack of trimethylsilyl group by FeCl4 anion to
form a carbon-carbon triple bond.[14f]
We proposed that FeCl3 first interacts with acid
chloride at the keto group instead of the chloro group
to initiate the catalytic reaction based on the litera-
ture reports.[15] To further verify the mechanism, three
reactions of phenylacetylene 2a with benzoyl bromide
in the presence of 10, 20 and 50% of FeCl3 under the
standard reaction conditions (Table 1) were carried
out. In all these reactions, b-bromoalkenyl ketone was
isolated as the only product in 76, 63 and 47% yields,
respectively (see Scheme 3 for detailed conditions).
There is no chloroacylation product 3b observed. The
results do not support a classical acylium ion, generat-
ed by removing the chloride anion from the acid chlo-
ride by FeCl3, as the intermediate. Instead, the results
favour a concerted pathway for the breaking of acyl-
halide bond via a 4-membered ring intermediate A.
In contrast, the reaction of benzoyl bromide with
hex-3-yne in the presence of 10, 20 and 50% of FeCl3
under the standard reaction conditions afforded a
mixture of b-bromo- and b-chloroalkenyl ketones as
shown in Scheme 3. These results clearly show that
16
1b
1g
2p
2p
93
76
17
18
1b
2q
2k
46
74
19
1m
[a]
Unless otherwise mentioned, all reactions were carried
out with acid chloride (1.0 mmol), alkyne
(1.25 mmol), FeCl3 (10 mol%) and CH3NO2 (2.0 mL) at
1
2
À158C for 6 h under N2.
[b]
Isolated yields.
try, based on our observed results. In the catalytic re- the chloride in FeCl3 is incorporated in the final prod-
action, FeCl3 likely acts as a Lewis acid interacting uct and support the proposed step-wise mechanism in
with the carbonyl group in the acid chloride as shown Scheme 2. It is important to mention that FeBr3 does
in Scheme 1 and Scheme 2. For the addition of acyl not catalyze the reaction of acid chloride with alkynes
chloride to terminal alkyne (Scheme 1), the reaction to give the corresponding addition product under the
probably proceeds via a four-membered ring transi- standard reaction conditions.
tion state A between the alkyne carbons and carbon-
chloride bond as suggested in Scheme 1. This pathway
explains the observed regiochemistry with the carbon- Conclusions
yl and chloro group of acid chloride adding to the ter-
minal carbon and internal carbon of alkyne in the In summary, we have successfully developed a very
final product 3. In addition, it also rationalizes the mild and convenient iron-catalyzed addition of acid
origin of the Z stereochemistry of the final product. chlorides to terminal alkynes to give the correspond-
The other arrangement A’ (see Table 2) is unfavoura- ing b-chloroalkenyl ketones in very good yields with
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Iron-Catalyzed Synthesis of b-Chlorovinyl and a,b-Alkynyl Ketones from Terminal and Silylated Alkynes
Scheme 2. Proposed mechanism for the addition of acid chlorides to internal alkynes.
Scheme 3. FeCl3-catalyzed addition of acid bromides to alkynes.
excellent regio- and stereoselectivity. Experiments Experimental Section
using acid bromides and terminal alkynes as the sub-
strates in the presence of FeCl3 reveal that the addi- General Procedure for the Iron-Catalyzed Synthesis
tion of acid bromide to terminal alkyne favours a con- of b-Chloroalkenyl Ketone Derivatives from Acid
certed pathway for the breaking of the acyl-halide Chlorides with Alkynes (Table 1 and Table 2)
bond via a 4-membered ring intermediate A. The
A sealed tube (15 mL) fitted with a septum containing FeCl3
present iron-catalyzed addition reaction is successfully
(01.00 mmol) was evacuated and purged with nitrogen gas
extended to alkynylsilanes to give alkynyl ketones.
three times. CHCl3 (2.0 mL), acid chloride (1.00 mmol) and
Further extension of the reaction to the intramolecu-
lar version and the detailed mechanistic investigations
are in progress.
alkyne (1.5 mmol) were added to the system and the reac-
tion mixture was stirred at 08C for 15 h under N2. The mix-
ture was filtered through a short Celite pad and washed
with dichloromethane several times. The filtrate was concen-
trated by vacuum and separated on a silica gel column using
hexane/EtOAc as eluent to give the corresponding pure b-
chloroalkenyl ketones.
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(Z)-3-Chloro-1-(4-methoxyphenyl)-3-phenylprop-2-en-1-
one (3a): Pale yellow solid; mp 87–888C; 1H NMR
(400 MHz, CDCl3): d=7.97 (d, J=8.8 Hz, 2H), 7.72 (t, J=
7.2 Hz, 2H), 7.43–7.40 (m, 3H), 7.26 (s, 1H), 6.94 (d, J=
8.8 Hz, 2H), 3.85 (s, 3H); 13C NMR (100 MHz, CDCl3): d=
188.7 (CO), 163 (C), 141.8 (C), 137.3 (C), 131.1 (2CH),
130.5 (C), 130.3 (CH), 128.6 (2CH), 127.0 (2CH), 121.9
(CH), 113.9 (2CH), 55.4 (CH3); HR-MS (EI+): m/z=
272.0598, calcd. for C16H13ClO2: 272.0604; IR (KBr): n=
2839, 1658, 1600, 1509, 1259, 1167, 1023 cmÀ1.
7.2 Hz, 2H), 7.44–7.42 (m, 3H), 7.28 (s, 1H), 7.14 (t, J=
8.8 Hz, 2H); 13C NMR (100 MHz, CDCl3): d=188.4 (CO),
165.8 (d, JC,F =253.3 Hz, C), 143.4 (C), 137.1 (C), 134.0 (d,
J
C,F =3.0 Hz, C), 131.3 (CH), 131.2 (CH), 130.6 (CH), 128.6
(2CH), 127.1 (2CH), 121.2 (CH), 115.9 (CH), 115.7 (CH);
HR-MS (EI+): m/z=260.0408, calcd. for C15H10ClFO:
260.0404; IR (KBr): n=1665, 1610, 1479, 1452, 1271,
1020 cmÀ1.
(Z)-1-(4-Bromophenyl)-3-chloro-3-phenylprop-2-en-1-one
(3h): Pale yellow solid; mp 78–808C; 1H NMR (400 MHz,
CDCl3): d=7.83 (d, J=8.4 Hz, 2H), 7.73 (dd, J=1.2 Hz, J=
7.2 Hz, 2H), 7.60 (d, J=8.4 Hz, 2H), 7.44–7.42 (m, 3H),
7.26 (s, 1H); 13C NMR (100 MHz, CDCl3): d=188.7 (CO),
143.9 (C), 137.0 (C), 136.4 (2C), 132.0 (2CH), 130.7 (CH),
130.1 (2CH), 128.4 (C), 127.1 (2CH), 120.8 (CH); HR-MS
(EI+): m/z=319.9602, calcd. for C15H10BrClO: 319.9604, IR
(KBr): n=1664, 1658, 1509, 1267, 1167, 1016 cmÀ1.
(Z)-3-Chloro-1,3-diphenylprop-2-en-1-one
(3b):
Pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=7.98 (d, J=
7.2 Hz, 2H), 7.74 (dd, J=2.0 Hz, J=8.0 Hz, 2H), 7.57 (t, J=
7.6 Hz, 1H), 7.49–7.41 (m, 5H), 7.33 (s, 1H); 13C NMR
(100 MHz, CDCl3): d=189.8 (CO), 143.2 (C), 137.7 (C),
137.3 (CH), 133.3 (C), 130.5 (CH), 128.6 (6CH), 127.1
(2CH), 121.4 (CH); HR-MS (EI+): m/z=242.0505, calcd.
for C15H11ClO: 242.0498; IR (KBr): n=1664, 1597, 1575,
1447, 1207, 1017 cmÀ1.
(Z)-3-Chloro-3-phenyl-1-(thiophen-2-yl)prop-2-en-1-one
1
(3i): Pale yellow oil; H NMR (400 MHz, CDCl3): d=7.75–
(Z)-3-Chloro-3-phenyl-1-o-tolylprop-2-en-1-one (3c): Col-
ourless oily liquid; 1H NMR (400 MHz, CDCl3): d=7.75–
7.72 (m, 2H), 7.65 (d, J=10.8 Hz, 1H), 7.46–7.38 (m, 4H),
7.28 (d, J=8.8 Hz, 2H), 7.17 (s, 1H), 2.58 (s, 3H), 13C NMR
(100 MHz, CDCl3): d=193.2 (CO), 142.9 (C), 138.4 (C),
137.2 (C), 131.8 (CH), 131.5 (CH), 130.5 (CH), 129.2 (CH),
128.6 (2CH), 127.1 (2CH), 125.7 (CH), 124.0 (CH), 20.8
(CH3); HR-MS (EI+): m/z=256.0655, calcd. for C16H13ClO:
256.0655; IR (KBr): n=3062, 2923, 1666, 1573, 1488, 1450,
817 cmÀ1.
7.72 (m, 3H), 7.65 (d, J=4.8 Hz, 1H), 7.46–7.39 (m, 3H),
7.32 (s, 1H), 7.12 (t, J=4.4 Hz 1H); 13C NMR (100 MHz,
CDCl3): d=180.9 (CO), 145.5 (C), 144.3 (C), 137 (C), 134.2
(CH), 132.0 (CH), 130.6 (CH), 128.6 (2CH), 128.2 (CH),
127.2 (2 CH), 120.3 (CH); HR-MS (EI+): m/z=248.0068,
calcd. for C13H9ClOS: 248.0063; IR (KBr): n=3100, 2341,
1643, 1586, 1574, 1412, 1245, 1061 cmÀ1.
(Z)-1-Chloro-1-phenylhept-1-en-3-one (3j): Colourless oil;
1H NMR (400 MHz, CDCl3): d=7.65 (d, J=6.8 Hz, 2H),
7.40–7.37 (m, 3H), 6.77 (s, 1H), 2.67 (t, J=7.2 Hz, 2H),
1.68–1.60 (m, 2H), 1.38–1.32 (m, 2H), 0.91 (t, J=7.2 Hz,
3H); 13C NMR (100 MHz, CDCl3): d=198.9 (CO), 142.2
(C), 137.4 (C), 130.5 (CH), 128.5 (2CH), 127.2 (2CH), 123.
8 (CH), 44.1 (CH2), 26.0 (CH2), 22.2 (CH2), 13.8 (CH3);
HR-MS (EI+): m/z=222.0817, calcd. for C13H15ClO:
222.0811; IR (KBr): n=2976, 2862, 2203, 1668, 1060 cmÀ1.
(Z)-1-Chloro-4-methyl-1-phenylpent-1-en-3-one (3k): Pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=7.63 (d, J=
7.2 Hz, 2H), 7.36–7.35 (m, 3H), 6.83 (s, 1H), 2.81 (m, 1H),
1.13 (d, J=6.8 Hz, 6H); 13C NMR (100 MHz, CDCl3): d=
201.8 (CO), 142.6 (C), 137.3 (C), 130.3 (CH), 128.4 (2CH)
127.0 (2CH), 122.1 (CH), 41.6 (CH), 17.8 (2 CH3); HR-MS
(EI+): m/z=208.0655, calcd. for C12H13ClO: 208.0655; IR
(KBr): n=2969, 2869, 2203, 1668, 1070 cmÀ1.
(Z)-3-chloro-3-phenyl-1-m-tolylprop-2-en-1-one (3d): Pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=7.81 (s, 1H),
7.80–7.75 (m, 3H), 7.46–7.44 (m, 3H), 7.39–7.37 (m, 2H),
7.34 (s, 1H), 2.44 (s, 3H) 13C NMR (100 MHz, CDCl3): d=
190.0 (CO), 143.0 (C), 138.5 (C), 137.7 (C), 137.3 (C), 134.1
(CH), 131.0 (CH), 129.0 (CH), 128.6 (2CH), 128.5 (CH),
127.0 (2CH), 125.9 (CH), 121.7 (CH), 21.3 (CH3); HR-MS
(EI+): m/z=256.0651, calcd. for C16H13ClO: 256.0655; IR
(KBr): n=3054, 2923, 1666, 1589, 1249, 1164, 1033 cmÀ1.
(Z)-3-Chloro-3-phenyl-1-p-tolylprop-2-en-1-one (3e): Col-
1
ourless oily liquid; H NMR (400 MHz, CDCl3): d=7.91 (d,
J=8.4 Hz, 2H), 7.77–7.74 (m, 2H), 7.56–7.43 (m, 3H), 7.32
(s, 1H), 7.29 (d, J=8.4 Hz, 2H), 2.42 (s, 3H);); 13C NMR
(100 MHz, CDCl3): d=189.5 (CO), 144.2 (C), 142.5 (C),
137.3 (C), 135.1 (C), 130.3 (CH), 129.5 (2CH), 129.3 (2CH),
128.8 (2CH), 127.0 (2CH), 121.7 (C), 21.6 (CH3); HR-MS
(EI+): m/z=256.0655, calcd. for C16H13ClO: 256.0655; IR
(KBr): n=3054, 2923, 1658, 1604, 1241, 1033, 825 cmÀ1.
(Z)-3-Chloro-1-(2-fluorophenyl)-3-phenylprop-2-en-1-one
(Z)-3-Chloro-1-phenyl-3-o-tolylprop-2-en-1-one (3l): Col-
1
ourless oily liquid; H NMR (400 MHz, CDCl3): d=8.00 (d,
J=7.2 Hz, 2H), 7.61–7.55 (m, 3H), 7.49 (t, J=7.6 Hz, 2H),
7.35–7.25 (m, 3H), 2.42 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=190.1 (CO), 144 (C), 138.7 (C), 138.0 (C), 137.5
(C), 133.5 (CH), 131.5 (CH), 128.9 (4CH), 128.8 (CH),
128.0 (CH), 124.6 (CH), 121.5 (CH), 21.6 (CH3); HR-MS
(EI+): m/z=256.0655, calcd. for C16H13ClO: 256.0655; IR
(KBr): n=2923 1664, 1597, 1575, 1447, 1207, 1017 cmÀ1.
1
(3f): Pale yellow oil; H NMR (400 MHz, CDCl3): d=7.87
(td, J=2.0 Hz, J=7.6 Hz, 1H), 7.74 (dd, J=1.2 Hz, J=
6.8 Hz, 2H), 7.54–7.48 (m, 1H), 7.45–7.37 (m, 4H), 7.25 (t,
J=7.6 Hz, 1H), 7.15–7.10 (m, 1H); 13C NMR (100 MHz,
CDCl3): d=186.5 (d, JC,F =2.9 Hz, CO), 161.2 (d, JC,F
251.9 Hz, C), 144.1 (C), 137.4 (2C), 134.4 (d, JC,F =9.6 Hz,
CH), 131.0 (CH), 130.7 (CH), 128.7 (2CH), 127.1 (2CH),
=
(Z)-3-Chloro-1-phenyl-3-m-tolylprop-2-en-1-one
(3m):
1
Colourless oily liquid; H NMR (400 MHz, CDCl3): d=7.89
(d, J=8.4 Hz, 2H), 7.55 (t, J=8.0 Hz, 1H), 7.46–7.40 (m,
3H), 7.28–7.17 (m, 4H), 2.37 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=187.7 (CO), 149.0 (C), 137.3 (C), 137.2 (C),
135.3 (C), 133.1 (CH), 130.1 (CH), 129.3 (CH), 128.5
(2CH), 128.3 (2CH), 127.8 (CH), 125.9 (CH), 122.6 (CH),
19.3 (CH3); HR-MS (EI+): m/z=256.0655, calcd. for
C16H13ClO: 256.0655; IR (KBr): n=2923 1662, 1591, 1545,
1443, 1205, 1017 cmÀ1.
124.6 (CH), 123.5 (d, JC,F =6.6 Hz, CH), 116.5 (d, JC,F
=
22.7 Hz, CH); HR-MS (EI+): m/z=260.0408, calcd. for
C15H10ClFO: 260.0404; IR (KBr): n=1665, 1610, 1479, 1452,
1271, 1020 cmÀ1.
(Z)-3-Chloro-1-(4-fluorophenyl)-3-phenylprop-2-en-1-one
1
(3g): Pale yellow oil; H NMR (400 MHz, CDCl3): d=8.01
(dd, J=5.2 Hz, J=8.8 Hz, 2H), 7.73 (dd, J=2.0 Hz, J=
464
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ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2012, 354, 457 – 468

Iron-Catalyzed Synthesis of b-Chlorovinyl and a,b-Alkynyl Ketones from Terminal and Silylated Alkynes
(Z)-3-Chloro-1-phenyl-3-p-tolylprop-2-en-1-one (3n): Pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=7.98 (d, J=
7.2 Hz, 2H), 7.65 (d, J=8.0 Hz, 2H), 7.57 (t, J=7.2 Hz,
1H), 7.47 (t, J=8.0 Hz, 2H), 7.33 (s, 1H), 7.23 (d, J=
7.6 Hz, 2H), 2.39 (s, 3H); 13C NMR (100 MHz, CDCl3): d=
189.8 (CO), 143.7 (C), 141.0 (C), 137.9 (C), 134.5 (C), 133.1
(C), 129.3 (2CH), 128.6 (4CH), 127.1 (2CH), 120.4 (CH),
21.3 (CH3); HR-MS (EI+): m/z=256.0651, calcd. for
C16H13ClO: 256.0655; IR (KBr): n=2837, 1658, 1608, 1509,
1267, 1167, 1023 cmÀ1.
(Z)-3-Chloro-3-(4-chlorophenyl)-1-phenylprop-2-en-1-one
(3o): Pale yellow solid; mp 55–578C; 1H NMR (400 MHz,
CDCl3): d=7.97 (dd, J=2.0 Hz, J=6.8 Hz, 2H), 7.67 (dd,
J=2.0 Hz, J=6.8 Hz, 2H), 7.57 (t, J=7.6 Hz, 1H), 7.48 (td,
J=1.2 Hz, J=7.2 Hz, 2H), 7.39 (dd, J=2.4 Hz, J=6.8 Hz,
2H), 7.30 (s, 1H); 13C NMR (100 MHz, CDCl3): d=189.6
(CO), 141.8 (C), 137.4 (C), 136.6 (C), 135.5 (C), 133.4 (CH),
128.9 (2CH), 128.7 (2CH), 128.6 (2CH), 128.4 (2CH), 121.8
(CH); HR-MS (EI+): m/z=276.0113, calcd. for C15H10Cl2O:
276.0109; IR (KBr): n=2357, 1665, 1596, 1487, 1448, 1095,
1012 cmÀ1.
(Z)-3-Chloro-1-phenylhex-2-en-1-one (3p): Pale yellow
oil; 1H NMR (400 MHz, CDCl3): d=7.89 (d, J=7.2 Hz,
2H), 7.54 (t, J=7.6 Hz, 1H), 7.44 (t, J=7.6 Hz, 2H), 7.11 (s,
1H), 2.94 (t, J=7.2 Hz, 2H), 1.75–1.65 (m, 2H), 0.96 (t, J=
7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=188.5 (CO),
157.3 (C), 138.1 (C), 132.9 (CH), 128.6 (2CH), 128.2 (2CH),
123.5 (CH), 38.1 (CH2), 21.1 (CH2), 13.2 (CH3); HR-MS
(EI+): m/z=208.0656, calcd. for C12H13ClO: 208.0655; IR
(KBr): n=2359, 2341, 1692, 1563, 1447 cmÀ1.
(Z)-3-Chloro-1-phenylundec-2-en-1-one (3q): Pale yellow
oil; 1H NMR (400 MHz, CDCl3): d=7.89 (d, J=7.2 Hz,
2H), 7.53 (t, J=7.6 Hz, 1H), 7.44 (t, J=7.6 Hz, 2H), 7.09 (s,
1H), 2.95 (t, J=7.2 Hz, 2H), 1.70–1.62 (m, 2H), 1.35–1.24
(m, 10H), 0.85 (t, J=6.4 Hz, 3H); 13C NMR (100 MHz,
CDCl3): d=188.5 (CO), 157.7 (C), 138.1 (C), 132.9 (CH),
128.6 (2CH), 128.2 (2CH), 123.2 (CH), 36.4 (CH2), 31.7
(CH2), 29.2 (CH2), 29.1 (CH2), 28.8 (CH2), 27.7 (CH2), 22.6
(CH2), 14.0 (CH3); HR-MS (EI+): m/z=278.1435, calcd. for
C17H23ClO: 278.1437; IR (KBr): n=2926, 2856, 1694, 1598,
1448, 1221 cmÀ1.
2.50 (q, J=7.6 Hz, 2H), 2.17 (q, J=7.2 Hz, 2H), 1.23–0.98
(m, 6H); 13C NMR (100 MHz, CDCl3): d=197.4 (CO),
137.4 (C), 137.3 (C), 136.4 (C), 133.7 (CH), 129.3 (2CH),
128.7 (2CH), 30.6 (CH2), 25.7 (CH2), 12.3 (CH3), 11.8
(CH3); HR-MS (EI+): m/z=222.0812, calcd. for C13H15ClO:
222.0811; IR (KBr): n=2974, 2937, 1732, 1669, 1449, 1286,
1244, 1168 cmÀ1.
(Z)-3-Chloro-2-ethyl-1-phenylpent-2-en-1-one (4b’): Pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=7.90 (dd, J=
1.0 Hz, J=7.6 Hz, 2H), 7.54 (t, J=7.2 Hz, 1H), 7.45 (t, J=
7.6 Hz, 2H), 2.51 (q, J=7.2 Hz, 2H), 2.39 (q, J=7.6 Hz,
2H), 1.21 (t, J=7.6 Hz, 3H), 1.02 (t, J=8.0 Hz, 3H);
13C NMR (100 MHz, CDCl3): d=197.1 (CO), 136.9 (C),
135.7 (C), 133.4 (CH), 129.4 (2CH), 128.6 (2CH), 28.2
(CH2), 24.7 (CH2), 13.1 (CH3), 12.5 (CH3); HR-MS (EI+):
m/z=222.0812, calcd. for C13H15ClO: 222.0811; IR (KBr):
d=2973, 2939, 1731, 1667, 1450, 1289, 1241, 1169 cmÀ1.
General Procedure for the Iron-Catalyzed Synthesis
of a,b-Alkynyl Ketone Derivatives from Acid
Chlorides with Alkynylsilanes
A sealed tube (15 mL) fitted with a septum containing FeCl3
(0.100 mmol) was evacuated and purged with nitrogen gas
three times. CH3NO2 (2.0 mL), acid chloride (1.00 mmol)
and alkynylsilenes (1.5 mmol) were added to the system and
the reaction mixture was stirred at À158C for 6 h under N2.
The mixture was filtered through a short Celite pad and
washed with dichloromethane several times. The filtrate was
concentrated by vacuum and separated on a silica gel
column using hexane/EtOAc as eluent to give the corre-
sponding pure a,b-alkynyl ketones.
1-(4-Methoxyphenyl)-3-phenylprop-2-yn-1-one (5a): Pale
1
yellow solid; mp 91–938C; H NMR (400 MHz, CDCl3): d=
8.17 (d, J=9.2 Hz, 2H), 7.65 (d, J=8.0 Hz, 2H), 7.45 (t, J=
7.2 Hz, 1H), 7.39 (t, J=7.6 Hz, 2H), 6.97 (d, J=8.8 Hz,
2H), 3.88 (s, 3H); 13C NMR (100 MHz, CDCl3): d=176.6
(CO), 164.4 (C), 132.9 (2CH), 131.9 (2CH), 130.5 (CH),
130.2 (C), 128.6 (2CH), 120.3 (C), 113.8 (2CH), 92.2 (C),
86.8 (C), 55.5 (CH3); HR-MS (EI+): m/z=236.0832, calcd.
for C16H12O2: 236.0837; IR (KBr): n=2198, 1628, 1600, 1507,
1307, 1260, 1160, 1031 cmÀ1.
(Z)-3-Chloro-4,4-dimethyl-1-phenylpent-2-en-1-one (3r):
1
Pale yellow oil; H NMR (400 MHz, CDCl3): d=7.90 (d, J=
1,3-Diphenylprop-2-yn-1-one (5b): Yellow oil; 1H NMR
(400 MHz, CDCl3): d=8.20 (d, J=7.2 Hz, 2H), 7.52 (d, J=
6.8 Hz, 2H), 7.59 (t, J=7.6 Hz, 1H), 7.48 (t, J=7.6 Hz, 2H),
7.43 (t, J=7.2 Hz, 1H), 7.37 (t, J=7.2 Hz, 2H); 13C NMR
(100 MHz, CDCl3): d=177.7 (CO), 136.6 (C), 133.9 (CH),
132.8 (2CH), 130.6 (CH), 129.3 (2CH), 128.5 (2CH), 128.4
(2CH), 119.8 (C), 92.9 (C), 86.7 (C); HR-MS (EI+): m/z=
206.0728, calcd. for C15H10O: 206.0732; IR (KBr): n=2198,
1628, 1600, 1507, 1307, 1260, 1160, 1031 cmÀ1.
3-Phenyl-1-o-tolylprop-2-yn-1-one (5c): Pale yellow oil;
1H NMR (400 MHz, CDCl3): d=8.31 (dd, J=0.8 Hz, J=
7.2 Hz, 1H), 7.65 (dd, J=1.2 Hz, J=8.0 Hz, 2H), 7.48–7.34
(m, 5H), 7.26 (d, J=8.8 Hz, 1H), 2.67 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=179.7 (CO), 140.4 (C), 135.7 (C),
133.1 (CH), 132.8 (3CH), 132.1 (CH), 130.5 (CH), 128.6
(2CH), 125.8 (CH), 120.3 (C), 91.7 (C), 88.3 (C), 21.8
(CH3); HR-MS (EI+): m/z=220.0885, calcd. for C16H12O:
220.0888; IR (KBr): n=2962,2923, 2198, 1643, 1280,
1203,1010, 802, 609 cmÀ1.
7.6 Hz, 2H), 7.54 (t, J=7.6 Hz, 1H), 7.44 (t, J=7.6 Hz, 2H),
6.69 (s, 1H), 1.29 (s, 9H); 13C NMR (100 MHz, CDCl3): d=
191.5 (CO), 154.6 (C), 137.3 (C), 133.2 (CH), 128.7 (2CH),
128.5 (2CH), 119.4 (CH), 39.8 (C), 28.6 (3CH3); HR-MS
(EI+): m/z=222.0804, calcd. for C13H15ClO: 222.0811; IR
(KBr): n=2969, 1671, 1598, 1448, 1220, 1015 cmÀ1.
(E)-3-Chloro-2-ethyl-1-(4-methoxyphenyl)pent-2-en-1-one
1
(4a): Pale yellow oil; H NMR (400 MHz, CDCl3): d=7.85
(d, J=8.8 Hz, 2H), 6.92 (d, J=8.8 Hz, 2H), 3.85 (s, 3H),
2.48 (q, J=7.6 Hz, 2H), 2.17 (q, J=7.6 Hz, 2H), 1.02–097
(m, 6H); 13C NMR (100 MHz, CDCl3): d=196.0 (CO),
164.1 (C), 137.4 (C), 136.4 (C), 131.8 (2CH), 131.8 (C),
129.4 (2 CH), 55.4 (CH3), 30.6 (CH2), 25.8 (CH2), 12.3
(CH3), 11.8 (CH3); HR-MS (EI+): m/z=252.0913, calcd. for
C14H17ClO2: 252.0917; IR (KBr): n=2970, 2935, 1598, 1250,
1159 cmÀ1.
(E)-3-Chloro-2-ethyl-1-phenylpent-2-en-1-one (4b): Pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=7.88 (d, J=
7.2 Hz, 2H), 7.57 (t, J=7.2 Hz, 1H), 7.46 (t, J=7.6 Hz, 2H),
Adv. Synth. Catal. 2012, 354, 457 – 468
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asc.wiley-vch.de
465

Parthasarathy Gandeepan et al.
FULL PAPERS
3-Phenyl-1-m-tolylprop-2-yn-1-one (5d): Pale yellow oil;
1H NMR (400 MHz, CDCl3): d=8.02 (d, J=7.6 Hz, 1H),
7.99 (S, 1H), 7.66 (dd, J=1.2 Hz, J=6.4 Hz, 2H), 7.46–7.38
(m, 5H), 2.43 (s, 3H); 13C NMR (100 MHz, CDCl3): d=
178.1 (CO), 138.4 (C), 136.8 (C), 134.9 (CH), 132.9 (2CH),
130.6 (CH), 129.7 (CH), 128.6 (2CH), 128.4 (CH), 127.0
(CH), 120.1 (C), 92.8 (C), 86.9 (C), 21.2 (CH3); HR-MS
(EI+): m/z=220.0887, calcd. for C16H12O: 220.0888; IR
(KBr): n=3062, 2923, 2206, 1643, 1295, 1164, 817 cmÀ1.
3-Phenyl-1-p-tolylprop-2-yn-1-one (5e): Pale yellow solid;
mp 87–88; 1H NMR (400 MHz, CDCl3): d=8.11 (d, J=
8.4 Hz, 2H), 7.67 (d, J=6.8 Hz, 2H), 7.48 (t, J=8.4 Hz,
1H), 7.46–7.39 (m, 2H), 7.31 (d, J=8.0 Hz, 2H), 2.44 (s,
3H); 13C NMR (100 MHz, CDCl3): d=177.6 (CO), 145.2
(C), 134.5 (C), 132.9 (2CH), 130.6 (CH), 129.6 (2CH), 129.3
(2CH), 128.6 (2CH), 120.2 (C), 92.5 (C), 86.9 (C), 21.7
(CH3); HR-MS (EI+): m/z=220.0881, calcd. for C16H12O:
220.0888; IR (KBr): n=3054, 2923, 2198, 1635, 1604, 1288,
1172, 825 cmÀ1.
1-(2-Fluorophenyl)-3-phenylprop-2-yn-1-one (5f): Pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=8.12–8.02 (m,
1H), 7.65 (d, J=7.2 Hz, 2H), 7.60–7.55 (m, 1H), 7.47 (d, J=
7.6 Hz, 1H), 7.46–7.38 (m, 2H), 7.28 (td, J=2.8 Hz, J=
6.8 Hz, 1H), 7.19 (t, J=8.0 Hz, 1H); 13C NMR (100 MHz,
CDCl3): d=174.1 (CO), 162.0 (d, JC,F =259.9 Hz, C), 135.5
(d, JC,F =9.1 Hz, CH), 133.1 (2CH), 131.7 (CH), 130.8 (CH),
128.6 (2CH), 124.1 (d, JC,F =3.7 Hz, CH), 120.0 (C), 117.0
(d, JC,F =21.2 Hz, CH), 92.9 (C), 88.4 (C); HR-MS (EI+):
m/z=224.0635, calcd. for C15H9FO: 224.0637; IR (KBr): n=
3062, 2198, 1643, 1481, 1450, 1311, 1010, 833 cmÀ1.
(100 MHz, CDCl3): d=178.1 (CO), 142.3 (C), 137.2 (C),
134.3 (CH), 133.9 (CH), 131.1 (CH), 130.1 (CH), 129.7
(2CH), 128.9 (2CH), 126.2 (CH), 120.1 (C), 92.4 (C), 91.0
(C), 21.1 (CH3); HR-MS (EI+): m/z=220.0881, calcd. for
C16H12O: 220.0888, found ; IR (KBr): n=3062, 2923, 2190,
1643, 1450, 1288, 1010, 833 cmÀ1.
1-Phenyl-3-m-tolylprop-2-yn-1-one (5k): Pale yellow oil;
1H NMR (400 MHz, CDCl3): d=8.22 (dd, J=1.6 Hz, J=
8.4 Hz, 2H), 7.60 td, J=3.2 Hz, J=13.6 Hz, 1H), 7.52–7.46
(m, 4H), 7.29 (d, J=7.6 Hz, 1H), 7.27 (s, 1H), 2.38 (s, 3H);
13C NMR (100 MHz, CDCl3): d=178.2 (CO), 138.7 (C),
137.1 (C), 134.3 (CH), 133.7 (CH), 132.0 (CH), 130.4 (CH),
129.7 (2CH), 128.8 (3CH), 120.1 (C), 93.7 (C), 86.9 (C),
21.4 (CH3); HR-MS (EI+): m/z=220.0884, calcd. for
C16H12O 220.0888; IR (KBr): n=3062, 2923, 2198, 1643,
1581, 1234, 1164, 902 cmÀ1.
1-Phenyl-3-p-tolylprop-2-yn-1-one (5l): Pale yellow solid;
1
mp 70–718C; H NMR (400 MHz, CDCl3): d=8.19 (d, J=
7.2 Hz, 2H), 7.59 (t, J=7.2 Hz, 1H), 7.53 (d, J=7.6 Hz,
2H), 7.47 (t, J=7.6 Hz, 2H), 7.16 (d, J=7.6 Hz, 2H), 2.33
(s, 3H); 13C NMR (100 MHz, CDCl3): d=178.2 (CO), 141.8
(C), 137.1 (C), 134.2 (CH), 133.3 (2CH), 129.7 (2CH) 128.8
(4CH) 117.1 (C), 94.1 (C), 87.0 (C), 21.9 (CH3); HR-MS
(EI+): m/z=220.0887, calcd. for C16H12O 220.0888; IR
(KBr): n=3059, 2923, 2195, 1643, 1581, 1234, 1164,
902 cmÀ1.
3-(4-Chlorophenyl)-1-phenylprop-2-yn-1-one (5m): Pale
1
yellow solid; mp 106–1078C; H NMR (400 MHz, CDCl3):
d=8.20 (d, J=7.6 Hz, 2H), 7.65–7.60 (m, 3H), 7.52 (t, J=
7.2 Hz, 2H), 7.41 (d, J=8.4 Hz, 2H); 13C NMR (100 MHz,
CDCl3): d=177.8 (CO), 137.1 (C), 136.7 (C), 134.2 (3CH),
129.5 (2CH), 129.1 (2CH), 128.6 (2CH), 118.5 (C), 91.5 (C),
87.5 (C); HR-MS (EI+): m/z=240.0539, calcd. for
C15H9ClO: 240.0342; IR (KBr): n=2923, 2198, 1635, 1295,
1017 cmÀ1.
1-(4-Fluorophenyl)-3-phenylprop-2-yn-1-one (5g): Pale
1
yellow solid; mp 61–638C; H NMR (400 MHz, CDCl3): d=
8.18 (dd, J=2.0 Hz, J=6.8 Hz, 2H), 7.62 (dd, J=1.2 Hz, J=
6.8 Hz, 2H), 7.42 (t, J=7.2 Hz, 1H), 7.36 (t, J=8.4 Hz, 2H),
7.14 (t, J=8.8 Hz, 2H); 13C NMR (100 MHz, CDCl3): d=
176.0 (CO), 166.2 (d, JC,F =254.7 Hz, C), 133.1 (C), 132.8
(2CH), 132.0 (CH), 131.9 (CH), 130.7 (CH), 128.5 (2 CH),
119.6 (C), 115.7 (CH), 115.5 (CH), 93.1 (C), 86.4 (C); HR-
MS (EI+): m/z=224.0639, calcd. for C15H9FO 224.0637; IR
(KBr): n=2205, 1635, 1225, 1146 cmÀ1.
3-Phenyl-1-(thiophen-2-yl)prop-2-yn-1-one (5n): Pale
1
yellow solid; mp 53–558C; H NMR (400 MHz, CDCl3): d=
7.98 (d, J=3.6 Hz, 1H), 7.73 (d, J=4.8 Hz, 1H), 7.63 (d, J=
8.4 Hz, 2H), 7.46 (t, J=6.8 Hz, 1H), 7.39 (t, J=8.0 Hz, 2H),
7.16 (t, J=4.8 Hz, 1H); 13C NMR (100 MHz, CDCl3): d=
169.7 (CO), 144.8 (C), 135.2 (CH), 135.0 (CH),132.9 (2CH),
130.8 (CH), 128.6 (2CH), 128.2 (CH), 119.8 (C), 91.6 (C),
86.4 (C); HR-MS (EI+): m/z=212.0291, calcd. for C13H8OS:
212.0296; IR (KBr): n=2199, 1617, 1513, 1409, 1358, 1229.
1212, 1052 cmÀ1.
1-(4-Bromophenyl)-3-phenylprop-2-yn-1-one (5h): White
1
solid; mp 109–1108C; H NMR (400 MHz, CDCl3): d=8.05
(d, J=8.4 Hz, 2H), 7.67–7.63 (m, 4H), 7.47 (t, J=7.2 Hz,
1H), 7.41 (t, J=7.6 Hz, 2H); 13C NMR (100 MHz, CDCl3):
d=176.8 (CO), 135.6 (C), 133.0 (2 CH), 131.9 (2CH), 130.9
(3CH), 129.5 (C), 128.7 (2CH), 93.6 (C), 86.5 (C); HR-MS
(EI+): m/z=283.9835, calcd. for C15H9BrO: 283.9837; IR
(KBr): n=2198, 1733, 1717, 1652, 1558, 1206, 1066,
1005 cmÀ1.
1
1-Phenylhept-1-yn-3-one (5o): Pale yellow solid; H NMR
(400 MHz, CDCl3): d=7.55 (dd, J=2.0 Hz, J=6.0 Hz, 2H),
7.42 (td, J=2.0 Hz, J=7.2 Hz, 1H), 7.35 (td, J=1.6 Hz, J=
7.2 Hz, 2H), 2.64 (t, J=7.2 Hz, 2H), 1.69–1.67 (m, 2H),
1.40–1.35 (m, 2H), 0.92 (t, J=7.2 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=188.1 (CO), 132.8 (2CH), 130.5
(CH), 128.5 (2CH), 119.9 (C), 90.4 (C), 87.7 (C), 45.1
(CH2), 26.1 (CH2), 22.0 (CH2), 13.7 (CH3); HR-MS (EI+):
m/z=186.1044, calcd. for C13H14O: 186.1045; IR (KBr): n=
2959, 2873, 2203, 1671, 1070 cmÀ1.
4,4-Dimethyl-1-phenylpent-2-yn-1-one (5p): Colourless
oil; 1H NMR (400 MHz, CDCl3): d=8.09 (d, J=8.0 Hz,
2H), 7.56 (td, J=1.2 Hz, J=7.6 Hz, 1H), 7.44 (t, J=7.6 Hz,
2H), 1.36 (s, 9H); 13C NMR (100 MHz, CDCl3): d=177.9
(CO), 136.7 (C), 133.5 (CH), 129.1 (2CH), 128.2 (2CH),
103.5 (C), 77.8 (C), 29.8 (3CH3), 27.7 (C); HR-MS (EI+):
1-(4-Chlorophenyl)-3-phenylprop-2-yn-1-one (5i): Colour-
1
less solid; mp 104–1058C; H NMR (400 MHz, CDCl3): d=
8.13 (d, J=2.0 Hz, J=6.8 Hz, 2H), 7.66 (dd, J=1.2 Hz, J=
8.0 Hz, 2H), 7.48–7.39 (m, 5H); 13C NMR (100 MHz,
CDCl3): d=176.6 (CO), 140.6 (C), 135.2 (C), 133.0 (2CH),
130.9 (CH), 130.8 (2CH), 128.9 (2CH), 128.7 (2CH), 119.8
(C), 93.6 (C), 86.5 (C); HR-MS (EI+): m/z=240.0340, calcd.
for C15H9ClO: 240.0342; IR (KBr): n=2198, 1643, 1581,
1280, 840 cmÀ1.
1-Phenyl-3-o-tolylprop-2-yn-1-one (5j): Pale yellow oil;
1H NMR (400 MHz, CDCl3): d=8.22 (d, J=8.0 Hz, 2H),
7.63–7.58 (m, 2H), 7.49 (t, J=7.6 Hz, 2H), 7.34 (t, J=
7.6 Hz, 1H), 7.25–7.18 (m, 2H), 2.56 (s, 3H); 13C NMR
466
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ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2012, 354, 457 – 468

Iron-Catalyzed Synthesis of b-Chlorovinyl and a,b-Alkynyl Ketones from Terminal and Silylated Alkynes
m/z=186.1037, calcd. for C13H14O: 186.1045; IR (KBr): n=
2958, 2217, 1652, 1598, 1504, 1284, 1229, 1151 cmÀ1.
65, 2448–2449; g) H. E. Zimmerman, D. H. Paskovich,
J. Am. Chem. Soc. 1964, 86, 2149–2160; h) A. Ianni,
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Savari, H. Sharghi, Synthesis 2004, 2165–2168; j) A.
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Chem. Int. Ed. 2009, 48, 9592–9594; l) T. Fujihara, T.
Iwai, J. Terao, Y. Tsuji, Synlett 2010, 2537–2548.
4,4-Dimethyl-1-phenylpent-2-yn-1-one (5q): Colourless
oil; 1H NMR (400 MHz, CDCl3): d=8.09 (d, J=8.0 Hz,
2H), 7.56 (td, J=1.2 Hz, J=7.6 Hz, 1H), 7.44 (t, J=7.6 Hz,
2H), 1.36 (s, 9H); 13C NMR (100 MHz, CDCl3): d=177.9
(CO), 136.7 (C), 133.5 (CH), 129.1 (2CH), 128.2 (2CH),
103.5 (C), 77.8 (C), 29.8 (3CH3), 27.7 (C); HR-MS (EI+):
m/z=186.1037, calcd. for C13H14O: 186.1045; IR (KBr): n=
2958, 2217, 1652, 1598, 1504, 1284, 1229, 1151 cmÀ1.
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1-Phenylbut-2-yn-1-one (5r): Colourless oil; 1H NMR
(400 MHz, CDCl3): d=8.10 (d, J=8.0 Hz, 2H), 7.56 (t, J=
7.2 Hz, 1H), 7.44 (t, J=7.6 Hz, 2H), 2.12 (s, 3H); 13C NMR
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129.4 (2CH), 128.4 (2CH), 92.4 (C), 78.9 (C), 4.2 (CH3);
HR-MS (EI+): m/z=144.0572, calcd. for C10H8O: 144.0575;
IR (KBr): n=2972, 2211, 1652, 1598, 1504, 1151 cmÀ1.
1-(Naphthalen-2-yl)-3-phenylprop-2-yn-1-one (5s): Pale
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1
yellow solid; mp 94–958C; H NMR (400 MHz, CDCl3): d=
Soc. 2009, 131, 6668–6669.
8.78 (s, 1H), 8.20 (d, J=8.8 Hz, 1H), 8.02 (d, J=7.6 Hz,
1H), 7.90 (t, J=8.8 Hz, 2H), 7.72 (d, J=7.2 Hz, 2H), 7.62
(t, J=7.6 Hz, 1H), 7.56 (t, J=7.6 Hz, 1H), 7.49 (t, J=
7.2 Hz, 1H), 7.43 (t, J=8.0 Hz, 2H); 13C NMR (100 MHz,
CDCl3): d=177.9 (CO), 136.1 (C), 134.4 (C), 133.0 (2CH),
132.6 (CH). 132.4 (C), 130.7 (CH), 129.8 (CH), 129.0 (CH),
128.7 (2CH), 128.5 (CH), 127.9 (CH), 126.9 (CH), 123.9
(CH), 120.2 (C), 93.0 (C), 87.0 (C); HR-MS (EI+): m/z=
256.0879, calcd. for C19H12O: 256.0888; IR (KBr): n=2200,
1635, 1623, 1300, 1181, 1123 cmÀ1.
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Acknowledgements
We thank the National Science Council of the Republic of
China (NSC-100–2119M-007-003) for support of this re-
search.
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Adv. Synth. Catal. 2012, 354, 457 – 468