Utility of dysprosium as a reductant in coupling reactions of acyl chlorides: The synthesis of amides and diaryl-substituted acetylenes

Article abstract of DOI:10.1021/om200080f

Reduction of acyl chlorides with dysprosium metal has been studied. The reducing ability of dysprosium metal is solvent-dependent. Dysprosium metal, which requires neither any additive nor pretreatment, can promote the cross-coupling of acyl chlorides in DMF or DEF to give amides in good yields. When the reaction was performed in N,N-dimethylacetamide, the reductive self-coupling reaction of aroyl chloride took place smoothly and afforded the diaryl-substituted acetylenes in moderate to good yield.

Full text of DOI:10.1021/om200080f

ARTICLE
pubs.acs.org/Organometallics
Utility of Dysprosium as a Reductant in Coupling Reactions of Acyl
Chlorides: The Synthesis of Amides and Diaryl-Substituted Acetylenes
Weifeng Chen, Kebin Li, Ziqiang Hu, Liliang Wang, Guoqiao Lai,* and Zhifang Li*
Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University,
Hangzhou, 310012, Zhejiang, People’s Republic of China
S Supporting Information
b
ABSTRACT: Reduction of acyl chlorides with dysprosium
metal has been studied. The reducing ability of dysprosium
metal is solvent-dependent. Dysprosium metal, which requires
neither any additive nor pretreatment, can promote the cross-
coupling of acyl chlorides in DMF or DEF to give amides in
good yields. When the reaction was performed in N,N-dimethylacetamide, the reductive self-coupling reaction of aroyl chloride took
place smoothly and afforded the diaryl-substituted acetylenes in moderate to good yield.
’ INTRODUCTION
metal as a reducing agent in organic transformation will open a
new fertile area. However, to the best of our knowledge, only few
papers using dysprosium metal itself directly in organic synthesis
without any activator or pretreatment have been reported.13b
Herein, we describe that the synthesis of amides and diaryl-
substituted acetylenes by applying a dysprosium powder-pro-
moted coupling reaction of acyl chlorides and found that the
reduction ability of dysprosium metal and the kind of coupling
products were significantly solvent-dependent.
Samarium diiodide as a versatile reagent has been widely used
in organic synthesis.1ꢀ3 However, a stronger single electron
transfer reducing reagent than samarium diiodie is sometimes
required. The addition of hexamethylphosphoramide (HMPA)
to samarium diiodide is a solution because it can effectively
enhance its reduction potential.4 Nevertheless, HMPA is highly
carcinogenic; thus powerful and readily available alternatives are
strongly desirable. Recently, some “new” soluble divalent lanthanide
reagents, LnI2 (Ln = Nd,6 Dy,7 Tm8) whose reduction potential is
much higher than that of SmI2 [oxidation reduction potential of
Ln3þ/Ln2þ in aqueous solution, Nd (ꢀ2.6), Dy (ꢀ2.5), Tm
(ꢀ2.3), and Sm (ꢀ1.55)]9 have been reported.10 For example,
’ RESULTS AND DISCUSSION
The reduction of acyl chlorides has been investigated extensively,
and the products are highly dependent on the reducing agents used.
For example, symmetrical ketones were formed as a nickel or
enneacarbonyl diiron lead was used as the reductant.18 Tetraphenyl
furan was isolated as the major product when low-valent titanium
species were used as the reducing agents.19 The reduction of aroyl
chlorides with samarium diiodide yielded R-diketones, R-hydroxy
ketones, and (Z)-R,R0-stilbenediol dibenzoates based on the reac-
tion conditions employed.20 Recently, Zhang reported the reduc-
tion of aroyl chlorides with samarium metal in DMF and afforded
o-aroylbenzoins, 1,2-diarylethanones, and (Z)-R,R0-stilbenediol
dibenzoates in moderate to good yields.21 Herein, we wish to
further report the lanthanoid metals (Nd, Gd, and Dy)-pro-
moted coupling reactions of acyl chlorides. Two novel kinds of
products resulting from the reductive coupling were afforded,
and still different pathways other than those previously reported
were proposed.
NdI2,6a DyI2,7b or TmI2 allows the Barbier-type reaction of
8b
ketone and alkyl chloride to take place smoothly even at low
temperature, while the SmI2/HMPA system does not work
under similar conditions. The zerovalent lanthaniod metals, such
as Sm, Nd, Gd, Dy, and Yb, are stable in air, nontoxic, cheap, and
also bear strong reduction potential. However, direct use of
zerovalent lanthanoid metals themselves in organic synthesis is
still rare. The advantages of the direct use of lanthaniod metals
are the easy operation and electron economies compared with
divalent lanthanoid species. However, the disadvantages are also
distinct such as the heterogeneous nature in organic solvents and
lower reactivity. In order to enhance the reduction ability of
lanthanoid metals, usually activating agents are required. The
additive commonly employed include iodine,11 Me3SiBr/HMPA,12
13
MenSiCl4ꢀn
,
hydrochloric acid,14 alkyl halides,15 etc. Recently,
Ogawa reported that photoirradiation could dramatically increase
the reduction ability of some rare earth metals (e.g., Ce, Nd, Sm,
and Eu) toward the reductive deiodation of iodoalkanes.16 By
applying this technology, the reductive coupling of acid chlorides
with styrenes using neodymium metal as a reductant has been
realized.17 Metallic dysprosium is stable in air, and its reducing
power (Dy3þ/Dy = ꢀ2.35) is comparable with that of magnesium
(Mg3þ/Mg = ꢀ2.37). Therefore, the direct use of dysprosium
Our studies found that the reducing ability of lanthanoid
metals (Nd, Gd, and Dy) and the kind of products in this
coupling reaction are highly solvent-dependent. The effects of
the lanthanoid metals, solvent, time, and temperature on the
reductive coupling of acyl chlorides are summarized in Table 1.
Received: January 27, 2011
Published: March 09, 2011
r
2011 American Chemical Society
2026
dx.doi.org/10.1021/om200080f Organometallics 2011, 30, 2026–2030
|

Organometallics
ARTICLE
Table 1. Ln-Induced Reductive Coupling of Benzoyl Chlor-
ide in a Series of Solventsa
Table 2. Dysprosium-Induced Cross-Coupling of Acyl
Chlorides in N,N-Dimethylformamide (DMF) or N,
N-Diethylformamide (DEF)a
yield (%)b
entry Ln solvent temperature (°C) time (min)
2a
95
3a
entry
acyl chloride (1aꢀi)
solvent product yield (%)b
1
Dy DMF
25
25
25
25
25
25
25
25
80
65
81
70
100
80
25
20
20
1
benzoyl chloride (1a)
benzoyl chloride (1a)
DMF
DEF
2a
4a
2b
2c
2d
4b
2e
2f
91
81
89
93
91
92
93
94
89
82
66c
2
Nd DMF
88
89
7
2
3
Gd DMF
20
trace
43
3
4-methylbenzoyl chloride (1b) DMF
4
Dy DMAC
Nd DMAC
Gd DMAC
Sm DMAC
Dy DMAC
Dy DMAC
Dy THF
20
4
2-chlorobenzoyl chloride (1c)
3-chlorobenzoyl chloride (1d)
3-chlorobenzoyl chloride (1d)
DMF
DMF
DEF
5
30
5
6
30
6
7
30
7
4-bromobenzoyl chloride (1e) DMF
8
30
8
65
86c
8
1-naphthoyl chloride (1f)
2-naphthoyl chloride (1g)
2-phenylacetyl chloride (1h)
heptanoyl chloride (1i)
DMF
DMF
DMF
DMF
9
180
120
120
120
120
60
5
d
9
2g
2h
2i
10
11
12
13
14
15
10
11
d
d
d
e
Dy CH3CN
Dy DME
a Unless otherwise noted, aroyl chloride (5 mmol) and dysprosium
(2 mmol) were allowed to react in DMF (10 mL) or DEF (10 mL) at rt
whin 20 min. b Isolated based on acyl chloride used. c 2 h.
Dy toluene
Dy pyridine
Dy DME
f
120
a Reaction conditions: Benzoyl chloride (5 mmol), Ln (2 mmol), solvent
(10 mL). b Isolated yield based on benzoyl chloride used. c Excess
(35%) rather than 3a were isolated (entry 15). Thus the self-
coupling of benzoyl chloride with dysprosium powder at 80 °C in
N,N-dimethylacetamide to give 1,2-diphenylethyne (3a) was
developed as the standard reaction conditions.
amount of dysprosium (4 mmol) was used. d No reaction. Complex
e
mixture was formed. f Catalytic amount of iodine was used; 1,
2-diphenylethanone (40%) and methyl benzoate (35%) were isolated.
On the basis of the reductive cross-coupling of benzoyl
chloride with dysprosium metal, next, we subsequently studied
the scope of the dysprosium/DMF system induced coupling
reaction of acyl chlorides. As shown in Table 2, a variety of
amides were obtained in good to excellent yields. Notably, in this
Dy-promoted reaction, aliphatic acyl chlorides, such as 2-pheny-
lacetyl chloride (1h) and heptanoyl chloride (1i), also worked
well to give the corresponding N,N-dimethyl-2-phenylacetamide
(2h) and N,N-dimethylheptanamide (2i) in 82% and 66%
isolated yields, respectively (entries 10 and 11). When benzoyl
chloride and 3-chlorobenzoyl chloride were treated with metallic
dysprosium in N,N-diethylformamide (DEF), N,N-diethylben-
zamide (4a) and 3-chloro-N,N-diethylbenzamide (4b) were
produced in good yields (entries 2 and 6).
From the experimental results, it is reasonable to propose
that the reaction proceeded through two pathways. Path 1
involves a radical mechanism. Thus DMF as a solvent with
strong polarity may play an important role in stabilizing the
intermediate and dissolving the dysprosium salts formed in the
reaction since the reaction does not work in THF, toluene, and
DME. In path 2, first, DMF decomposed into dimethylamine
and carbon monoxide induced by dysprosium; then the re-
leased dimethylamine is captured by benzoyl chloride to give N,
N-dimethylbenzoylamide (2a). However, when DMF or N-
methyl-N-phenylformamide in neat was treated with dyspro-
sium in 3 h, neither dimethylamine or N-methylbenzenamine
could be detected. It should be noted that when benzoyl
chloride was treated with neat N-methyl-N-phenylformamide
in the presence of dysprosium, the cross-coupling product
Benzoyl chloride was chosen as the model substrate to investi-
gate the coupling reaction with lanthannoid metals (Nd, Gd, and
Dy). When benzoyl chloride (5 mmol) was treated with lantha-
noid metals (Dy, Nd, Gd) (2 mmol) in DMF at room tempera-
ture, the color of the reaction mixture changed rapidly from
colorless to brown, and an exothermic reaction was observed
(Table 1, entries 1ꢀ3). N,N-Dimethylbenzamide (2a) was un-
expectedly obtained in high yields after simple workup (Table 1,
entries 1ꢀ3). The reactions were generally clean, and only N,
N-dimethylbenzamide (2a) was isolated in good yield. The
formation of 2a should be ascribed to the cross-coupling of
benzoyl chloride and DMF. It should be noted that no self-
coupling products of the benzoyl chloride could be detected in
the GC-MS analysis of the crude products. Interestingly, when
benzoyl chloride (5 mmol) was treated with dysprosium
(2 mmol) in N,N-dimethylacetamide (DMAC) at room tem-
perature, 1,2-diphenylethyne (3a) was obtained in 43% isolated
yield (entry 4). The yield of 3a was increased to 65% by
prolonging the reaction time (30 min) (entry 8). It should be
noted that when an excess amount of dysprosium (4 mmol) was
used, the yield of 3a was greatly improved (entry 9). Neody-
mium, gadolinium, or samarium did not promote the coupling
reaction, and the starting benzoyl chloride was recovered quan-
titatively (entries 5ꢀ7). When the coupling reaction was carried
out in THF, CH3CN, DME, toluene, etc., no reaction occurred at
all (entries 10ꢀ13). With pyridine as the solvent, a complex
mixture was obtained. When a catalytic amount of iodine was
used in DME, 1,2-diphenylethanone (40%) and methyl benzoate
2027
dx.doi.org/10.1021/om200080f |Organometallics 2011, 30, 2026–2030

Organometallics
ARTICLE
Scheme 1. Possible Mechanism of Dysprosium-Promoted Cross-Coupling of Benzoyl Chloride in DMF
Table 3. Dysprosium-Induced Self-Coupling of Aroyl
Scheme 2. Possible Mechanism of Dysprosium-Induced
Coupling of Benzoyl Chloride in DMAC
Chloride in N,N-Dimethylacetamide (DMAC)a
entry
aroyl chloride
time (h) product yield (%)b
1
benzoyl chloride (1a)
1
3
3a
3a
3b
3c
3d
3e
3f
46
2
benzoyl chloride (1a)
86
3
2-methylbenzoyl chloride (1b)
3-methylbenzoyl chloride (1c)
4-methylbenzoyl chloride (1d)
4-ethylbenzoyl chloride (1e)
4-butylbenzoyl chloride (1f)
4-methoxybenzoyl chloride (1g)
1-naphthoyl chloride (1h)
4-chlorobenzoyl chloride (1i)
4-chlorobenzoyl chloride (1i)
heptanoyl chloride (1j)
3
85
4
3
81
5
3
80
6
3
72
7
3
70
metallic dysprosium in DMAC, diaryl-substituted acetylenes
were obtained. As shown in Table 3, aroyl chlorides with
electron-donating groups underwent the self-coupling reaction
smoothly to give the corresponding diaryl-substituted acetylenes
in good yields (entries 1ꢀ7). With aroyl chlorides with electron-
withdrawing groups, such as 1-naphthoyl chloride and 4-chlor-
obenzoyl chloride, the corresponding diaryl-substituted acety-
lenes were isolated in low yields. In these reactions, R-diketones
were isolated as the major products (entries 9 and 10). In the case
of 1-naphthoyl chloride, the low yield may be due to the steric
effect, not the inductive effect (Table 3, entry 9). When the reaction
time was prolonged, the overreduction product, 1,2-bis(4-chloro-
phenyl)ethane, was detected in 12% yield by GC-MS analysis of the
crude products (entry 11).7b However, when heptanoyl chloride
was treated under similar reaction conditions, no reaction
occurred (entry 12).
A possible mechanism for this self-coupling reaction of aroyl
chlorides with metallic dysprosium is shown in Scheme 2. It is
likely that the reaction begins with an electron transfer from
dysprosium to benzoyl chloride (1a); thus benzoyl radical is
formed (A). The benzoyl radical (A) may dimerize into benzyl
(B), which immediately accepts one equivalent of electrons from
dysprosium metal to give C. (Z)-Enediolate (E) is formed when
C accepts two more equivalents of electrons.21 (Z)-Enediolate
(E) may undergo reductive deoxygenation in the presence of
low-valent dysprosium species, giving the corresponding 1,
2-diphenylethyne (3a).22,23
8
5
3g
3h
3i
60
9
5
35c
30d
12e
NR
10
11
12
5
12
5
3j
a Unless otherwise specified, aroyl chloride (5 mmol) and dysprosium
(4 mmol) were allowed to react in DMAC at 80 °C. b Isolated yields
based on aroyl chloride used. c 1,2-Di(naphthalen-1-yl)ethane-1,2-dione
was obtained in 40% yield. d 1,2-Bis(4-chlorophenyl)ethane-1,2-dione
was obtained in 45% yield. e 1,2-Bis(4-chlorophenyl)ethane was isolated
in 12% yield.
N-methyl-N-phenylbenzamide was obtained in 85% isolated
yield (eq 1). Thus, for the mechanism of the cross-coupling
reaction of benzoyl chloride in DMF or DEF, path 1 is
preferred.
The reductive conversion of aroyl chlorides into diarylacety-
lenes with lithium amalgam was first reported by Horner.22 The
electrochemical reduction of aroyl chlorides on a Hg cathode in
DMF/LiClO4 yielded 1,2- diphenylacetylenes using a two-step
procedure.23 We found that when aroyl chloride was treated with
To provide support for the above mechanism, benzil (B) was
treated with dysprosium metal in DMAC. Gratifyingly, the
2028
dx.doi.org/10.1021/om200080f |Organometallics 2011, 30, 2026–2030

Organometallics
ARTICLE
reaction did afford 1,2-diphenylethyne (3a) in 56% isolated
206 (Mþ, 100), 191 (9), 165 (6), 139 (4), 102 (11), 89 (12), 76 (7),
63 (4).
yield.24
1,2-Bis(4-ethylphenyl)ethyne (3e) (ref 26): white solid; mp
110ꢀ112 °C; 1H NMR ((CD3)2CO, 400 MHz) δ 7.45ꢀ7.43 (d, 4H, J =
8 Hz), 7.26ꢀ7.24 (d, 4H, J = 8 Hz), 2.67ꢀ2.63 (q, 4H, J = 4 Hz),
1.23ꢀ1.19 (t, 6H, J = 4 Hz); 13C NMR ((CD3)2CO, 100 MHz) δ 144.8,
131.4, 128.0, 120.6, 88.7, 28.4, 14.9; MS m/z (%) 234 (Mþ, 93.0), 219
(100), 204 (32), 189 (9), 139 (4), 117 (4), 102 (25), 89 (8), 76 (3).
1,2-Bis(4-butylphenyl)ethyne (3f): white solid; mp 41ꢀ42 °C
(lit. mp 41 °C); 1H NMR ((CD3)2CO, 400 MHz) δ 7.47ꢀ7.42 (d, 4H,
J = 8 Hz), 7.24ꢀ7.22 (d, 4H, J = 8 Hz), 2.65ꢀ2.59 (m, 4H), 1.63ꢀ1.56
(m, 4H), 1.39ꢀ1.28 (m, 4H), 0.94ꢀ0.90 (m, 6H); 13C NMR
((CD3)2CO, 100 MHz) δ 143.4, 131.3, 128.7, 128.6, 120.6, 88.8,
35.2, 33.4, 22.1, 13.3; MS m/z (%) 290 (Mþ, 73), 247(100), 204
(51), 189 (8), 161 (7), 115 (3), 102 (2).
1,2-Bis(4-methoxyphenyl)ethyne (3h) (ref 22): white solid;
mp 140ꢀ144 °C (lit.22 mp 142ꢀ144 °C); 1H NMR ((CD3)2CO, 400
MHz) δ 7.45ꢀ7.43 (d, 4H, J = 8.6 Hz), 6.96ꢀ6.94 (d, 4H, J = 8.6 Hz),
3.82 (s, 6H); 13C NMR ((CD3)2CO, 100 MHz) δ 159.7, 132.7, 115.5,
114.1, 88.7, 54.8; MS m/z (%) 238 (Mþ, 100), 223 (77), 195 (22), 180
(12), 152 (29), 119 (18), 98 (3), 75 (2).
In conclusion, we have found that dysprosium metal without
any activation and pretreatment could promote the cross- or self-
coupling reaction of acyl chlorides effectively in DMF, DEF, or
DMAC, which afford the amides or diaryl-substituted acetylenes
in good yields. Especially, it should provide an attractive alter-
native route to diaryl-substituted acetylenes due to the readily
available and less expensive starting materials, operational sim-
plicity, high yields of the products, and high potential for large-
scale synthesis. Furthermore, the investigation may demonstrate
that dysprosium metal as a very powerful reductant would find its
unique usages in organic transformation since it proved to have
somewhat different reactivity and oxygen-philicity compared
with the samarium and traditional divalent lanthanide complexes.
1,2-Di(naphthalen-1-yl)ethyne (3g) (ref 26): white solid; mp
1
124ꢀ126 °C (lit.26 mp 125ꢀ126 °C); H NMR ((CD3)2CO, 400
MHz) δ 8.60ꢀ8.58 (d, 2H, J = 8 Hz), 8.10ꢀ8.00 (m, 6H), 7.73ꢀ7.59
(m, 6H); 13C NMR ((CD3)2CO, 100 MHz) δ 133.5, 133.1, 130.7,
129.2, 128.6, 127.2, 126.7, 125.9, 125.6, 120.7, 92.2; MS m/z (%) 278
(Mþ, 100), 138 (30), 125 (10), 112 (3), 87 (1), 63 (1).
’ EXPERIMENTAL SECTION
1H and 13C NMR spectra were recorded on a Bruker AV-400 MHZ
instrument as DMSO solutions using TMS as an internal standard.
Chemical shifts (δ) are reported in ppm, and coupling constants J are
given in Hz. GC-MS were measured with a Trance 2000 DSQ mass
spectrometer. IR spectra were taken as thin films with a Nicolet 5700
infrared spectrometer. Elemental analysis was performed on a Vario EL-
III instrument. Melting points are uncorrected. Column chromatogra-
phy was performed with silica gel (Wako Pure Chemical Industries, Ltd.,
Wakogel C-300). Thin-layer chromatography was performed on 0.25
mm E. Merck silica gel plates (GF-254). All the reactions in this paper
were performed under a nitrogen atmosphere.
General Procedure for Dysprosium-Induced Self-Cou-
pling of Aroyl Chlorides. A mixture of aroyl chloride (5 mmol)
and dysprosium powder (4 mmol) in DMAC (10 mL) was heated at
80 °C under a N2 atmosphere for the time given in Table 3. The reaction
was monitored by thin-layer chromatography. The volatile materials
were removed under reduced pressure, and the residue was purified by
flash column chromatograph (SiO2, petroleum ether/ethyl acetate,
10:1) to afford the pure diaryl-substituted acetylenes.
1,2-Bis(4-chlorophenyl)ethyne(3i) (ref 22): white solid; mp
175ꢀ177 °C (lit.22 mp 174 °C); 1H NMR ((CD3)2CO, 400 MHz) δ
7.53ꢀ7.51 (d, 4H, J = 8.8 Hz), 7.45ꢀ7.44 (d, 4H, J = 8.8 Hz); 13C NMR
((CD3)2CO, 100 MHz) δ 133.9, 129.8, 128.0, 121.7, 89.2; MS m/z (%)
246 (Mþ, 100), 176 (50),98(4), 75 (2).
’ ASSOCIATED CONTENT
S
Supporting Information. Detailed experimental proce-
b
dure for the synthesis of amides (2aꢀi and 4a,b). This material is
available free of charge via the Internet at http://pubs.acs.org.
’ AUTHOR INFORMATION
Corresponding Author
*E-mail: zhifanglee@hznu.edu.cn.
1,2-Diphenylethyne (3a) (ref 22): white solid; mp 59ꢀ60.5 °C
(lit.22 mp 60 °C); 1H NMR (DMSO, 400 MHz) δ 7.55ꢀ7.53 (m, 4H),
7.42ꢀ7.40 (m, 6H); 13C NMR (DMSO, 100 MHz) δ 129.3, 129.2,
122.8, 89.8; MS m/z (%) 178 (Mþ, 100), 152 (12), 126 (7), 89 (13),76
(17), 51 (3).
’ ACKNOWLEDGMENT
This work was supported by the National Natural Science
Foundation of China (20802014) and Zhejiang Provincial High
Technology Research Program (2009R50016).
1,2-Di-o-tolylethyne (3b) (ref 25): white solid; mp 58ꢀ60 °C
(lit.25 mp 57ꢀ59 °C); 1H NMR ((CD3)2CO, 400 MHz) δ 7.53ꢀ7.51
(d, 2H, J = 8 Hz), 7.32ꢀ7.20 (m, 6H), 2.51 (s, 6H); 13C NMR
((CD3)2CO, 100 MHz) δ 139.7, 131.7, 129.6, 128.5, 125.8, 123.1,
92.1, 20.1; MS m/z (%) 206 (Mþ, 100), 191 (31), 178 (16), 165 (13),
128 (8), 115 (13), 91 (18), 89 (24), 63 (7).
’ REFERENCES
(1) Namy, J. L.; Girard, P.; Kagan, H. B. New J. Chem. 1977, 1, 5–7.
(2) Girard, P.; Namy, J. L.; Kagan, H. B . J. Am. Chem. Soc. 1980,
102, 2693–2698. (b) Namy, J. L.; Girard, P.; Kagan, H. B.; Caro, P. E.
New J. Chem. 1981, 5, 479–484.(c) Kagan, H. B.; Namy, J. L. In
Handbook on the Physics and Chemistry of Rare Earths; Gschneidner,
K. A., Jr., Eyring, L., Eds.; Elsevier: Amsterdam, 1984; Vol. 6, Chapter
50.
(3) For reviews, see: (a) Kagan, H. B.; Namy, J. L. Tetrahedron 1986,
42, 6573–6614. (b) Soderquist, J. A. Aldrichim. Acta 1991, 24, 15–23. (c)
Molander, G. A. Chem. Rev. 1992, 92, 29–68. (d) Krief, A.; Laval, A. M.
Chem. Rev. 1999, 99, 745–777.(e) Molander, G. A.; Harris, C. R. In
Encyclopedia of Reagents for Organic Synthesis; Paquette, L. A., Ed.; Wiley:
New York, 1995; Vol. 6, pp 4428ꢀ4432. (f) Jung, D. Y; Kim, Y. H.
1,2-Di-m-tolylethyne (3c) (ref 23): white solid; mp 75ꢀ76 °C
1
(lit.23 mp 74 °C); H NMR ((CD3)2CO, 400 MHz) δ 7.35ꢀ7.21
(m, 8H), 2.34 (s, 6H); 13C NMR ((CD3)2CO, 100 MHz) δ 138.2,
131.9, 129.2, 128.5, 123.1, 88.9, 20.3; MS m/z (%) 206 (Mþ, 100), 189
(18), 165 (7), 115 (5), 102 (10), 76 (5).
1,2-Di-p-tolylethyne (3d) (ref 22): white solid; mp 134 °C (lit.22
1
mp 131ꢀ133 °C); H NMR ((CD3)2CO, 400 MHz) δ 7.42ꢀ7.40
(d, 4H, J = 8 Hz), 7.23ꢀ7.21 (d, 4H, J = 8 Hz), 2.35 (s, 6H); 13C NMR
((CD3)2CO, 100 MHz) δ138.4, 131.3, 129.2, 120.3, 88.6, 20.5; MS m/z(%)
2029
dx.doi.org/10.1021/om200080f |Organometallics 2011, 30, 2026–2030

Organometallics
ARTICLE
Synlett 2005, 3019–3032. (g) Gopalaiah, K.; Kagan, H. B. New J. Chem.
2008, 32, 607–637. (h) Nicolaou, K. C.; Ellery, S. P.; Chen, J. S. Angew.
Chem., Int. Ed. 2009, 48, 7140–7165. (i) Concellon, J. M.; Rodriguez-Solla,
H.; Concellon, C.; del Amo, V. Chem. Soc. Rev. 2010, 53, 1914–1920. (j)
Gong, H. J.; Jia, X. S.; Zai, H. B. Chin. J. Org. Chem. 2010, 30, 939–950.
(4) (a) Otsubo, K.; Inanaga, J.; Yamaguchi, N. Tetrahedron Lett. 1986,
57, 4437. (b) Flowers, R. A.; Shabangi, M. Tetrahedron Lett. 1997, 38, 1137.
(5) Vogel, E. W.; Van Zeeland, A. A.; Raaymakers Jansen Verplanke,
C. A.; Zijlstra, J. A. Mutat. Res. 1985, 150, 241–260.
(6) (a) Evans, W. J.; Workman, P. S.; Allen, N. T. Org. Lett. 2003,
5, 2041–2042. (b) Burin, M. E.; Smirnova, M. V.; Fukin, G. K.; Baranov,
E. V.; Bochkarev, M. N. Eur. J. Inorg. Chem. 2006, 351–356. (c) Fagin,
A. A.; Balashova, T. V.; Kusyaev, D. M.; Kulikova, T. I.; Glukhova, T. A.;
Makarenko, N. P.; Kurskii, Y. A.; Evans, W. J.; Bochkarev, M. N.
Polyhedron 2006, 25, 1105–1110. (d) Jaroschik, F.; Momin, A.; Nief,
F.; Le Goff, X. F.; Deacon, G. B.; Junk, P. C. Angew. Chem., Int. Ed. 2009,
48, 1117–1121.
Tetrahedron Lett. 1984, 25, 2869–2872. (c) Collin, J.; Namy, J. L.;
Dallemer, F.; Kagan, H. B. J. Org. Chem. 1991, 56, 3118–3122. (d)
Namy, J. L.; Colomb, M.; Kagan, H. B. Tetrahedron Lett. 1994,
35, 1723–1726. (e) Li, Z.; Zhang, Y. Chin. J. Chem. 2001, 19, 634–636.
(21) Liu, Y.; Wang, X.; Zhang, Y. Synth. Commun. 2004,
34, 4009–4022.
(22) Horner, L.; Dickerhof, K. Chem. Ber. 1983, 116, 1615–1622.
(23) Polo, C.; Quintanilla, G. M.; Barba, F. Synth. Commun. 1994,
24, 907–915.
(24) Hydrazine-induced deoxygenation of R-diketones: (a) Cope,
A. C.; Smith, D. S.; Cotter, R. J. Organic Syntheses; Wiley: New York,
1963; Collect. Vol. IV, p 377. (b) Barton, H. R. D.; Bashiardes, G.;
Fourrey, J. L. Tetrahdron 1988, 44, 147–162. (c) Xue, Z.; Sieber, W. J.;
Knobler, C. B.; Daesz, H. D. J. Am. Chem. Soc. 1990, 112, 1825–1833.
Active uranium-induced reduction of dicarbonyls: Kahn, B. E.; Reike,
R. D. J. Organomet. Chem. 1988, 346, C45–48.
(25) Busacca, C. A.; Farber, E.; Deyoung, J.; Campbell, S.; Gonnella,
N. C.; Grinberg, N.; Haddad, N.; Lee, H.; Ma, S.; Reeves, D.; Shen, S.;
Senanayake, C. H. Org. Lett. 2009, 11, 5594–5597.
(7) (a) Bochkarev, M. N.; Fagin, A. A. Chem.—Eur. J. 1999,
5, 2990–2992. (b) Evans, W. J.; Allen, N. T.; Ziller, J. W. J. Am. Chem.
Soc. 2000, 122, 11749–11750. (c) Xiang, X.; Shen, Q. S.; Wang, J. L.;
Zhu, Z. Y.; Huang, W.; Zhou, X. G. Organometallics 2008,
27, 1959–1962.
(26) Volodymyr, S.; Jolanta, L.; Karol, G.. J. Org. Chem. 2004,
69, 7748–7751.
(8) (a) Bochkarev, M. N.; Fedushkin, I. L.; Fagin, A. A.; Petrovskaya,
T. V.; Ziller, J. W.; Broomhall-Dillard, R. N.; Evans, W. J. Angew. Chem.,
Int. Ed. Engl. 1997, 36, 133–135. (b) Evans, W. J.; Allen, N. T. J. Am.
Chem. Soc. 2000, 122, 2118–2119. (c) Turcitu, D.; Nief, F.; Ricard, L.
Chem.—Eur. J. 2003, 9, 4916–4923.
(9) Morss, L. R. Chem. Rev. 1976, 76, 827.
(10) (a) Evans, W. J.; Allen, N. T.; Ziller, J. W. J. Am. Chem. Soc.
2001, 123, 7927–7928. (b) Bochkarev, M. N.; Fedushin, I. L.; Dechert,
S.; Fagin, A. A.; Schumann, H. Angew. Chem., Int. Ed. 2001, 40, 3176. (c)
Izod, K. Angew. Chem., Int. Ed. 2002, 41, 743. (d) Evans, W. J.; Allen,
N. T.; Ziller, J. W. Angew. Chem., Int. Ed. 2002, 41, 359. (e) Evans, W. J.;
Zucchi, G.; Ziller, J. W. J. Am. Chem. Soc. 2003, 125, 10–11. (f)
Bochkarev, M. N.; khoroshenkov, G. V.; Schumann, H.; Dechert, S.
J. Am. Chem. Soc. 2003, 125, 2894–2895. (g) Katkova, M. A.; Fukin,
G. K.; Fagin, A. A.; Bochkarev, M. N. J. Organomet. Chem. 2003,
682, 218–223. (h) Bochkarev, M. N. Coord. Chem. Rev. 2004,
248, 835. (i) Jaroschik, F.; Momin, A.; Nief, F.; Le Goff, X. F.; Deacon,
G. B.; Junk, P. C. Angew. Chem., Int. Ed. 2009, 48, 1117–1121. (g) Nief, F.
Dalton Trans. 2010, 39, 6589–6598.
(11) (a) Imamoto, T.; Kusumoto, T.; Hatanaka, Y.; Yokoyama, M.
Tetrahedron Lett. 1982, 23, 1353. (b) Yanada, R.; Negoro, N.; Okaniwa,
M.; Ibuka, T. Tetrahedron 1999, 55, 13947. (c) Nishino, T.; Nishiyama,
Y.; Sonada, N. J. Org. Chem. 2002, 67, 966. (d) Nishino, T.; Okada, M.;
Kuroki, T.; Watanabe, T.; Nishiyama, Y.; Sonada, N. J. Org. Chem. 2002,
67, 8696.
(12) (a) Taniguchi, Y.; Kuno, T.; Nakahashi, M.; Takaki, K.;
Fujiwara, Y. Appl. Organomet. Chem. 1995, 9, 491. (b) Jin, W. S.;
Makioka, Y.; Kitamura, T.; Fujiwara, Y. J. Org. Chem. 2001, 66, 514.
(13) (a) Wang, L.; Zhang, Y. Tetrahedron 1998, 54, 11129–11140.
(b) Zhu, Z. Y.; Wang, J. L.; Zhang, Z. X.; Xiang, X.; Zhou, X. G.
Organometallics 2002, 26, 2499–2500.
(14) Talukdar, S.; Fang, J. M. J. Org. Chem. 2001, 66, 330.
(15) (a) Ghatak, A.; Becker, F. F.; Banik, B. K. Tetrahedron Lett.
2000, 41, 3793–3796.
(16) (a) Ogawa, A.; Sumino, Y.; Nanke, T.; Ohya, S.; Sonada, N.;
Hirao, T. J. Am. Chem. Soc. 1997, 119, 2745. (b) Ogawa, A.; Ohya, S.;
Hirao, T. Chem. Lett. 1997, 275. (c) Sumino, Y.; Harato, N.; Tomisaka,
Y.; Ogawa, A. Tetrahedron 2003, 59, 10499. (d) Tomisaka, Y.; Nomoto,
A.; Ogawa, A. Tetrahedron Lett. 2009, 50, 584–586.
(17) Li, Z.; Tomisaka, Y.; Nomoto, A.; Zhang, Y.; Ogawa, A. Chem.
Lett. 2009, 16–17.
(18) Flood, T. C. Tetrahedron Lett. 1977, 18, 3861–3864.
(19) Dams, R.; Malinowski, M.; Westdorp, I.; Geise, H. J. J. Org.
Chem. 1981, 46, 2406–2407.
(20) (a) Girard, P.; Couffignal, R.; Kagan, H. B. Tetrahedron Lett.
1981, 22, 3959–3960. (b) Souppe, J.; Namy, J. L.; Kagan, H. B.
2030
dx.doi.org/10.1021/om200080f |Organometallics 2011, 30, 2026–2030