Selective Catalytic Formation of Cross-Tetramers from Tetrafluoroethylene, Ethylene, Alkynes, and Aldehydes via Nickelacycles as Key Reaction Intermediates

Article abstract of DOI:10.1021/jacs.8b11671

In the presence of a catalytic amount of Ni(cod)₂ (cod = 1,5-cyclooctadiene) and PCy₃ (Cy = cyclohexyl), the cross-tetramerization of tetrafluoroethylene (TFE), ethylene, alkynes, and aldehydes leads to a variety of fluorine-containing enone derivatives. This reaction is the first example of a highly selective cross-tetramerization between four different unsaturated compounds. Stoichiometric reactions revealed that the present reaction involves partially fluorinated five- and seven-membered nickelacycles as key reaction intermediates.

Full text of DOI:10.1021/jacs.8b11671

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Communication
Selective Catalytic Formation of Cross-Tetramers from
Tetrafluoroethylene, Ethylene, Alkynes, and Aldehydes
via Nickelacycles as Key Reaction Intermediates
Takuya Kawashima, Masato Ohashi, and Sensuke Ogoshi
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.8b11671 • Publication Date (Web): 06 Dec 2018
Downloaded from http://pubs.acs.org on December 6, 2018
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Journal of the American Chemical Society
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Selective Catalytic Formation of Cross-Tetramers from
Tetrafluoroethylene, Ethylene, Alkynes, and Aldehydes via
Nickelacycles as Key Reaction Intermediates
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Takuya Kawashima, Masato Ohashi,* and Sensuke Ogoshi*
Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan)
Supporting Information Placeholder
following reaction sequence: the oxidative cyclization of TFE and
ethylene with Ni(0) should
ABSTRACT: In the presence of a catalytic amount of Ni(cod)
cod = 1,5-cyclooctadiene) and PCy (Cy = cyclohexyl), the cross-
2
(
3
tetramerization of tetrafluoroethylene (TFE), ethylene, alkynes,
and aldehydes leads to a variety of fluorine-containing enone
derivatives. This reaction is the first example of a highly selective
cross-tetramerization between four different unsaturated
compounds. Stoichiometric reactions revealed that the present
reaction involves partially fluorinated five- and seven-membered
nickelacycles as key reaction intermediates.
Scheme 1. Working hypothesis.
F
F
F F
F
H
H
F
F
(a)
OM 2015 (Ref. 7a).
F
F
 Ni(0)
F
F
Ni
Ni
F F
F
(
TFE)
Ni(0)
F
F
O
R
+
Ni
A
F
F
R
F F
H
H
H
R
(
b)
O
F
 Ni(0)
F F
O
F
JACS 2015 (Ref. 7b).
Oxidative cyclizations with low-valent transition-metal
complexes have received increasing attention as a straightforward
and environmentally benign route to the construction of C−C bonds
F
F
F
F
H
H
(c)
F
Ni
 Ni(0)
F
F
F
F
F
F
1
,2
JACS
2
017 (Ref. 7c).
between two unsaturated compounds. Representative examples
are the transition-metal-catalyzed linear trimerization or
tetramerization of ethylene to 1-hexene or 1-octene, respectively,
via a five-membered metallacycle generated by the oxidative
O
R
O
R
Ni
B
F
R
F
F
H
F
F
F
H
H
(d)
O
Ni
 Ni(0)
F
F
F
This Work
3
cyclization of two molecules of ethylene. The development of
such oligomerizations represents an attractive research target given
yield five-membered nickelacycle A, as oxidative cyclizations
between electron-rich and -deficient substrates using Ni(0) are in
general kinetically much more favorable than those occurring
that α-olefins can be co-polymerized with ethylene to afford
4
polymers with improved properties. On the other hand, transition-
metal-catalyzed cross-trimerizations or -tetramerizations of two or
more different types of unsaturated compounds allow generating
complicated molecular structures in a highly atom-economical
manner and a single step. However, the number of hitherto
developed selective cross-trimerizations of unsaturated compounds
remains low, most likely due to potential side reactions that
11
between other substrate combinations. The sequential migratory
insertion of an alkyne and a molecule of ethylene into A would then
lead to a cross-tetramer via seven-membered nickelacycle B. The
chemoselective generation of B from A could be caused by the
exclusive coordination of the relatively electron-rich and sterically
less hindered linear alkynes, especially aliphatic alkynes such as 4-
octyne to the Ni(II) center in A. Another key feature for the
successful development of such cross-tetramerizations is the
inability of B to undergo not only β-hydride eliminations, but also
reductive eliminations that forms new C–C bonds, which is due to
the unique inertness of the bonds between transition metals and the
5
generate e.g. homo-coupling products. Cross-tetramerizations,
especially those using four different unsaturated compounds, have
not yet been reported.
We have been focusing on the usage of tetrafluoroethylene
(TFE) as an ideal C2 building block for the introduction of
fluorinated functionalized groups, considering that the
conventional use of the industrially economical feed stock TFE has
been limited mostly to the production of tetrafluoroethylene-based
1
2
perfluoroalkyl ligands. We then envisioned a further expansion of
this concept into a chemoselective cross-tetramerization of four
different unsaturated compounds, provided that the selective
formation of seven-membered nickelacycle B can be achieved even
in the presence of a fourth unsaturated compound. As aldehydes
exhibit a reactivity toward the five-membered nickelacycle A that
6
–10
polymers and copolymers with other alkenes.
We have
previously developed chemo- and regio-selective co- or cross-
trimerizations of TFE with unsaturated compounds in the presence
7
a,b
of a Ni(0) catalyst (Schemes 1a and 1b). More recently, we have
discovered an unprecedented Ni(0)-catalyzed cross-tetramerization
of TFE, alkynes, and two molecules of ethylene that affords
7b
is higher than that of ethylene (Scheme 1b), a nucleophilic
addition of B to an aldehyde rather than to ethylene should provide
the targeted cross-tetramer (Scheme 1d). Based on this hypothesis,
we explored the cross-tetramerization of TFE, ethylene, 4-octyne
7
c
7
,7,8,8-tetrafluoro-1,3-octadiene derivatives (Scheme 1c). So far,
we have rationalized this catalytic reaction in terms of the
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(
1a), and p-tolualdehyde (2a) in the presence of a Ni(0) catalyst,
(1c), and 6-undecyne (1d), furnished the desired cross-tetramers
(3aa-3da), while unsymmetrical alkynes (1e and 1f) yielded a
mixture of regioisomers (3ea and 3fa) with poor selectivity. The
use of 1-phenyl-1-hexyne (1g) afforded the desired product (3ga)
with moderate regioselectivity, albeit that the yield was low. When
tolan (1h) was used, the desired cross-tetramer (3ha) was not
obtained due to
1
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3
4
5
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8
9
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1
1
1
1
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4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
which exhibited unprecedentedly high selectivity.
Scheme 2. Ni(0)-catalyzed cross-tetramerization of TFE,
ethylene, 4-octyne (1a), and p-tolualdehyde (2a).
a,b
Scheme 3. Ni(0)-catalyzed cross-tetramerization of TFE,
O
Ar
a,b
1
0 mol% Ni(cod)2
ethylene, alkynes (1), and aldehydes (2).
F
F F
nPr
+
O
Ar
40 mol% PCy3
F
H
nPr
+
+
F
nPr
toluene, temp.
5 h
O
H
2a
F
F
nPr
R
F
F
10 mol% Ni(cod)2
F F
1a
3aa
R2
+
O
R
40 mol% PCy3
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
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9
0
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0
1
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9
0
Ar = p-tolyl
F
H
R2
(
2.0 atm) (2.0 atm)
(1.0 eq.)
+
F
+
4
0 ºC: 19%
R1
H
2
toluene, 100 °C,
5 h
F
F
R1
100 ºC: 60%
F
9% (66%)c,d
c
1
3
7
c
(2.5 atm) (2.5 atm)
(1.0 eq.)
Ar = p-tolyl
side-reaction products at 100 °C:
n
nPr
Pr
a) Scope of alkynes (aldehyde = 2a (R = p-tolyl))
F
F
nPr
nPr
Ar
O
Ar
3ba (R1 = R2 = Et): 54%
3ca (R1 = R2 = nBu): 63%
3ea (R1 = nPr, R2 = Me): 40% [56/44]c
3fa (R1 = nC7H15, R2 = Et): 54% [52/48]
H
F
nPr
F
Ar
O
F
F
nPr
a: 5%
F
O
3da (R1 = R2 = nC H11): 53%
3ga (R1 = nBu, R2 = Ph): (37%) [67/33]
H
F
5
3ha (R1 = R2 = Ph): (0%)
4
5aa: 8%
6%
b) Scope of aldehydes (alkyne = 1a (R1 = R2 = nPr))
3ab (R = Ph): 41% 3ao (R = 4-(EtOEt)2CHC6H4): 42%
ac (R = m-tolyl): 48%
a
General conditions: 1a (0.50 mmol), 2a (0.50 mmol), toluene (1.5
mL). The molar quantities of both gases (c.a. 4.0 mmol at 2.0 atm,
room temperature; estimated based on the ideal gas equation) were
absolutely larger than those of 1a and 2a. The yield of 3aa,
relative to 1a, was determined by GC analysis using tetradecane as
an internal standard. TFE (2.5 atm) and ethylene (2.5 atm) were
3
3ap (R = 4-PhC6H4): 48%
3aq (R = 1-naphthyl): (7%)
3ar (R = 2-naphthyl): 42%
3as (R = 2-fluorenyl): 52%
3ad (R = o-tolyl): (13%)
b
3ae (R = 3,5-Me C H ): 62%
2
6 3
t
3af (R = 3,5- Bu2C6H3): 83%
3ag (R = 3,5-(MeO)2C6H3): 20%
3ah (R = 4-anisyl): 57%
c
3at (R = 2-thienyl): 80%
d
employed. Isolated yield.
3au (R = 2-benzothienyl): 81%
3av (R = 3-benzothienyl): 22%e
3aw (R = 2-furyl): 76%
3ai (R = 4-NMe2C6H4): 33%
Based on the previously established optimal ligand and
ligand/Ni(0) ratio in the cross-tetramerization that leads to the
tetrafluoro-1,3-diene derivatives, a toluene solution of 1a and 2a
was exposed for 5 h at 40 °C to a gas mixture containing TFE (2.0
atm) and ethylene (2.0 atm) in the presence of Ni(cod)
3aj (R = 4-FC6H4): 47%
3ak (R = 4-MeCO2C6H4): 71%d
3ax (R = 2-benzofuryl): 29%
7
c
3
al (R = 4-CF3C6H4): 38%
am (R = 4-BpinC6H4): 58%
3ay (R = 3-dibenzo[b,d]furyl): 56%
3az (R = 1-methyl-2-pyrrolyl): 35%f
3
2 3
and PCy
3an (R = 3-vinylC6H4): 27%
3aa' (R = trans-cynnamyl): 54%
(10 and 40 mol%, respectively). Under these conditions, cross-
a
tetramer 3aa, a fluorine-containing enone derivative, was formed
in 19% yield (Scheme 2). Encouraged by this result, we attempted
to optimize the ligands and the ligand/Ni(0) ratio; however, all our
attempts confirmed that PCy
the use of 4 equiv of PCy
catalytic reaction. However, we discovered that the reaction
temperature is of paramount importance to this reaction, i.e.,
increasing the temperature to 100 °C improved the yield of 3aa to
2 3
General conditions: Ni(cod) (0.05 mmol), PCy (0.20 mmol),
alkynes (1; 0.50 mmol), aldehyde (2; 0.50 mmol), TFE (2.5 atm),
b
ethylene (2.5 atm), and toluene (1.5 mL). Isolated yield. The GC
3
is indeed the optimal ligand and that
relative to Ni(cod) accelerates the
yield is given in parentheses. The ratio of regioisomers is given in
c
d
3
2
square brackets. 20 mol% Ni(cod)
2
and 80 mol% PCy
3
. 20 mol%
1
3
e
Ni(cod)
2
, 80 mol% PCy
, 80 mol% PCy
and 80 mol% PCy
mixture of E/Z isomers (54/46).
the occurrence of trimerization of 1h and the Tishchenko reaction
3
, and 2k (0.75 mmol; 1.5 eq.). 20 mol%
f
Ni(cod)
2
3
, and 2v (1.00 mmol; 2.0 eq.), 24 h. 20
, 24 h. The product was a
mol% Ni(cod)
2
3
6
0%. Moreover, increasing the gas pressure (2.5 atm each) allowed
isolating 3aa in 66% yield (79% GC yield). The crude reaction
mixture also contains the three-component cross-tetramer (4a; 5%)
consisting of TFE, 1a, and two molecules of ethylene, the
15
2
of 2a prior to the gas pressurization. An attempt at employing (η -
CF =CF )Ni(PCy ) (6) as a catalyst precursor in this cross-
2 2 3 2
7
c
8d
1
1a
Tishchenko reaction product (6%), and a cyclobutene derivative
tetramerization of TFE, ethylene, 1h, and 2a was conducted in
anticipation of suppressing the advance consumption of 1h and 2a,
however, the target product 3ha was not obtained.
(
5aa; vide infra; 8%), whereas another possible ,-enone
1
4
derivative via the hydroacylation of 1a with 2a is not generated.
The thus required purification procedure, which includes column
chromatography on silica gel followed by recycling HPLC, is
responsible for the relatively low isolated yield of 3aa.
Consequently, the optimal reaction conditions were determined as:
Subsequently, we explored the substrate scope with respect to
various aldehydes (Scheme 3b). Benzaldehyde (2b) and m-
tolualdehyde (2c) furnished the corresponding cross-tetramers (3ab
and 3ac) in 41% and 48% yields, respectively, while o-
tolualdehyde (2d) afforded a diminished yield, which is probably
due to its increased steric demand. In the reactions with 3,5-
disubstituted benzaldehydes, 3,5-dimethylbenzaldehyde (2e) and
1
0 mol% Ni(cod)
2 3
and 40 mol% PCy in toluene at 100 °C under
an atmosphere of a gas mixture of TFE and ethylene (2.5 atm
1
3
each). It should be emphasized that an equimolar mixture of the
alkyne and aldehyde is sufficient to facilitate the desired cross-
tetramerization, which stands in stark contrast to another type of
selective four-component cross-tetramerization with TFE, styrene,
alkynes, and ethylene. In the catalytic reaction with styrene, the
formation of a kinetically less favored five-membered nickelacycle
generated by the oxidative cyclization of TFE and styrene with
Ni(0) requires the use of an excess of styrene.
3
,5-di-tert-butylbenzaldehyde (2f) yielded the corresponding
cross-tetramers (3ae or 3af) in 62% and 83% yield, respectively,
whereas 3,5-dimethoxybenzaldehyde (2g) hampered the cross-
7
c,d
tetramerization.
4-Anisaldehyde
(2h),
4-
dimethylaminobenzaldehyde (2i), 4-fluorobenzaldehyde (2j), and
methyl 4-formylbenzoate (2k) afforded the corresponding cross-
tetramers (3ah-3ak) in 57%, 33%, 47%, and 71% yield,
respectively. However, using 4-trifluoromethylbenzaldehyde (2l)
yielded the desired cross-tetramerization product (3al) in 38% yield
together with a considerable amount of 4a (55% GC yield in the
With the optimal reaction conditions in hand, we investigated the
scope and the limitations of this Ni-catalyzed cross-tetramerization
with respect to the alkyne substrates (Scheme 3a). The use of
symmetrical aliphatic alkynes, such as 1a, 3-hexyne (1b), 5-decyne
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O
Ar
crude mixture). Using p-boronate-substituted benzaldehyde 2m
O
Ar
2
.0 eq.
(2l)
F
F
Ph
1
2
3
4
5
6
7
8
9
furnished the corresponding cross-tetramer (3am) in 58% yield,
and the boronate moiety could be used in subsequent cross-
coupling reactions to synthesize highly functionalized derivatives.
In addition, reactions employing 3-vinylbenzaldehyde (2n), 4-
H
H
Et
1.0 eq. PCy3
Ph
F
F
F
C6D6,
00 °C, 24 h
F
F
Et
2.0 eq.
F
Et
1
10il: 76% (by 19F NMR)
(
1i)
F
F
F
Ar = p-CF C H
3
6
4
F
(
(
diethoxymethyl)benzaldehyde (2o), and 4-phenylbenzaldehyde
2p) also afforded the corresponding cross-tetramers (3an−3ap).
Ni
toluene,
40 °C, 24 h
Ni
(5 atm)
Ph
F
F
Cy3P
Cy3P
11: 44%
1
.0 eq. PCy3
H
The use of 1-naphthaldehyde (2q) hampered the reaction due to
steric congestion, whereas reactions using 2-naphthaldehyde (2r)
and 2-fluorenecarboxaldehyde (2s) afforded the corresponding
cross-tetramers (3ar and 3as) in moderate yields. The use of 2-
8
as above
F
F
Et
1
2i
naphthaldehyde-d
tetramer (3ar-d; 99% D) with a –CF
this catalytic system, thienyl aldehydes (2t-2v) and furyl aldehydes
2w-2y) are also applicable. Among these, 2-
thiophenecarboxaldehyde 2t and benzo[b]thiophene-2-
carboxaldehyde 2u yielded the cross-tetramers (3at and 3au) in
excellent yield (3at: 80% isolated and 98% GC yield; 3au: 81%
isolated and 98% GC yield). On the other hand, the reaction using
1
(2r-d; 99% D) yielded the corresponding cross-
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
CF D motif in 45% yield. In
2
(
1
-methyl-2-pyrrolecarboxaldehyde (2z) was slow and only a small
amount of the targeted product (3az) was isolated from the crude
reaction mixture. Moreover, the use of 2-pyridinecarboxaldehyde
did not yield the desired cross-tetramer. Aliphatic aldehydes, such
as octanal, cannot be used in this catalytic reaction due to the
formation of 4a. Conversely, trans-cinnamaldehyde (2a’) engages
in the reaction, leading to the desired cross-tetramer (3aa’) in 54%
Figure 1. ORTEP representation of 11 with thermal ellipsoids
set at the 30% probability level. All hydrogen atoms have been
omitted for clarity and only selected atoms are labelled.
1
5
yield. It should be noted that, in the reactions that afford the target
product 3 in relatively low yield, the starting materials of 1a and 2
were fully consumed as a result of the undesired formation of 4a,
2
Scheme 6. Stoichiometric reaction of ( -CF
2
CF
2 3 2
)Ni(PCy )
5
, and the Tishchenko reaction product.
(6) with a mixture of 1a and 2a.
To gain deeper insight into the reaction mechanism as well as the
origin of the unique chemoselectivity in this cross-tetramerization,
several stoichiometric reactions were carried out. The treatment of
nPr
nPr
nPr
F
F
F
F
nPr
nPr
Ar
O
Ar
F
+
+
Ni
6
F
7
a
1
3
nPr
toluene, 100 °C,
24 h
Ar = p-tolyl
either (CF
Ph)Ni(PCy
for 24 h led to the formation of the corresponding cross-tetramers
aa and 10aa in 75% and 61% yield, respectively (Scheme 4). It
2
CF
3
2
CH
2
CH
2
)Ni(PPh
3
)
2
(7) or ( : -CF
2
CF
2
CH
2
CH-
H
Cy3P
PCy3
H
F
O
) (8)7d with 2 equiv of 1a and 2a in toluene at 100 °C
F
1a
2a
5aa: 53% (d.r. = 1.6:1)
(4.0 eq.)
(2.0 eq.)
nPr
nPr
nPr
nPr
3
n
Pr
F
Ar
Ni(0)
nPr
F
F
should be emphasized that in the former reaction, an expected
cross-trimer (9a) that consists of TFE, ethylene, and 2a was not
generated, which stands in contrast to our previous observation that
the corresponding cross-trimer (9b) was obtained from the reaction
Ar
H
O
 Ni(0)
nPr
F
Ni
O
F
F
nPr
13
H
F F
we managed to isolate the corresponding seven-membered
nickelacycle (11) in 44% yield, and its molecular structure was
unambiguously determined by X-ray diffraction analysis (Scheme
5, Figure 1). Further treatment of 11 with 2 equiv of 2l in the
7
b
of 7 with benzaldehyde 2b. This result clearly supports the notion
that the insertion of the alkyne into the Ni–CH bond of the five-
membered nickelacycle is much faster than that of the aldehyde.
2
1
6
3 6 6
presence of an equimolar amount of PCy in C D at 100 °C for 24
We once again conducted a stoichiometric reaction of 8 with 2
equiv of 2-methyl-1-hexen-3-yne (1i) in order to trap a potential
h afforded the corresponding four-component cross-tetramer (10il)
in 76% yield. In contrast, complex 11 exhibited lower reactivity
toward ethylene, i.e., the reaction of 11 with ethylene (5 atm) did
not furnish the corresponding cross-tetramer (12i). These results
are consistent with our working hypothesis (Scheme 1). The
formation of the side-reaction product 5aa was rationalized based
on the results of a stoichiometric reaction between 6, 4 equiv of 1a,
and 2 equiv of 2a, which afforded 5aa in 53% isolated yield as a
mixture of diastereoisomers (Scheme 6). A plausible mechanism
for the formation of 5aa might involve the initial formation of an
acyclic dienone derivative (13) via a Ni(0)-mediated cross-
tetramerization of TFE, two molecules of 1a, and 2a, followed by
an oxidative cyclization of 13 with Ni(0) and a reductive
3
seven-membered nickelacycle intermediate with an  -butadienyl
17,18
moiety,
although attempts to isolate the nickelacycles from the
reactions of 8 with 1a or 1h have failed due to the occurrence of α-
7
c,19
fluorine elimination to yield Ni(II) fluoride species.
As a result,
Scheme 4. Stoichiometric reaction of five-membered
nickelacycles 7 and 8 with a mixture of 1a and 2a.
F
O
Ar
F
F
F
2.0 eq nPrCCnPr (1a)
.0 eq ArCHO (2a)
F F
H
Ar
2
H
F
F
nPr
Ni
7
toluene, 100 °C, 24 h
F
F
O
F
F
nPr
Ph3P
PPh3
3aa: 75%
9a: not generated
F
F
20
O
Ar
elimination.
F
F
Ph
F
F
as above
H
In conclusion, we have demonstrated that the cross-tetrameri-
zation of tetrafluoroethylene, ethylene, alkynes, and aldehydes
affords a variety of enone derivatives with fluoroalkyl chains. This
is the first example of a highly selective cross-tetramerization using
four different unsaturated compounds. The key reaction
intermediates are the partially fluorinated five- and seven-
membered nickelacycles.
nPr
Ni
Ar = p-tolyl
F
F
nPr
10aa: 61%
Cy3P
8
Scheme 5. Isolation of a seven-membered nickelacycle (11)
via a stoichiometric reaction between 8 and 1i.
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Catalyzed Three-Component Couplings via Internal Redox. J. Am. Chem.
ASSOCIATED CONTENT
Supporting Information
Soc. 2008, 130, 469−471. (b) Kobayashi, M.; Tanaka, K. Rhodium-
Catalyzed Linear Cross-Trimerization of Two Different Alkynes with an
Alkene and Two Different Alkenes with an Alkyne. Chem. Eur. J. 2012,
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
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3
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4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Detailed experimental procedures, analytical and spectral data for
all new compounds, and a CIF file for 11. The Supporting
Information is available free of charge on the ACS Publications
website at http://pubs.acs.org.
1
8, 9225–9229. (c) Ogata, K.; Atsuumi, Y.; Fukazawa, S. Highly
Chemoselective Nickel-Catalyzed Three-Component Cross-Trimerization
between Two Distinct Terminal Alkynes and an Internal Alkyne. Org. Lett.
2011, 13, 122–125. For a few examples for transition-metal-catalyzed co-
trimerizations, see: (d) Hoberg, H.; Hernandez, E. Nickel(0)−Catalysed
Synthesis of Unsaturated Carboxylic Acid Anilides from Ethene and Phenyl
Isocyanate. J. Chem. Soc., Chem. Commun. 1986, 544−545. (e) Sambaiah,
T., Li, L.-P.; Huang, D.-J. Lin, C.-H.; Rayabarapu, D. K.; Cheng, C.-H.
Highly Regio- and Stereoselective Cocyclotrimerization and Linear
Cotrimerization of α,β-Unsaturated Carbonyl Compounds with Alkynes
Catalyzed by Nickel Complexes. J. Org. Chem. 1999, 64, 3663–3670. (f)
Ogoshi, S.; Nishimura, A.; Haba, T.; Ohashi, M. Nickel-Catalyzed
Reactions between Enone and Two Ethylenes. Chem. Lett. 2009, 38,
1166−1167. (g) Nakao, Y.; Idei, H.; Kanyiva, K. S.; Hiyama, T. Direct
AUTHOR INFORMATION
Corresponding Author
ohashi@chem.eng.osaka-u.ac.jp
ogoshi@chem.eng.osaka-u.ac.jp
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
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6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Notes
The authors declare no competing financial interests.
Alkenylation and Alkylation of Pyridone Derivatives by Ni/AlMe
3
Catalysis. J. Am. Chem. Soc. 2009, 131, 15996–15997. (h) Ogoshi, S.;
Nishimura, A.; Ohashi, M. Nickel-Catalyzed [2 + 2 + 2] Cycloaddition of
Two Enones and an Alkyne. Org. Lett. 2010, 12, 3450–3452. (i) Horie, H.;
Kurahashi, T.; Matsubara, S. Selective Synthesis of Trienes and Dienes via
Nickel-Catalyzed Intermolecular Cotrimerization of Acrylates and Alkynes.
Chem. Commun. 2010, 46, 7229–7231. (j) Kaneda, K.; Terasawa, M.;
Imanaka, T.; Teranishi, S. Highly Selective Cotrimerization of Olefins
ACKNOWLEDGMENT
This work was partially supported by a Grant-in-Aid for Scientific
Research (A) (A16H02276), (B) (16KT0057 and 17H03057) from
the Japan Society for the Promotion of Science (JSPS).
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(12) For Ni, see: Dubinina, G. G.; Brennessel, W. W.; Miller, J. L. Vicic,
D. A. Exploring Trifluoromethylation Reactions at Nickel: A Structural and
Reactivity Study. Organometallics 2008, 27, 3933–3938.
(13) For further optimizations of the reaction conditions in the Ni(0)-
catalyzed cross-tetramerization, see the Supporting Information.
(14) Tsuda, T.; Kiyoi, T.; Saegusa, T.; Nickel(0)-Catalyzed
Hydroacylation of Alkynes with Aldehydes to ,-Enones. J. Org. Chem.
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(15) For the substrate scope with respect to other substrates in the Ni(0)-
catalyzed cross-tetramerization, see the Supporting Information.
(16) Ni(0)-catalyzed cross-tetramerization of TFE, styrene, 1a, and 2a
was sluggish to afford the desired product 8aa in 36% yield. See also the
Supporting Information in details.
(17) Nishimura, A.; Ohashi, M.; Ogoshi, S. Nickel-Catalyzed
Intermolecular [2 + 2] Cycloaddition of Conjugated Enynes with Alkenes.
J. Am. Chem. Soc. 2012, 134, 15692–15695.
(18) The stoichiometric reaction of 6 with 1i was also conducted. In
addition, attempts at the catalytic cross-tetramerization of TFE, ethylene,
1i, and 2a gave a desired cross-tetramer in <1 % yield. See also the
supporting information in detail.
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
(9) For selected recent references involving the transformation of TFE
into valuable organofluorine compounds by other groups, see: (a) Takahira,
Y.; Morizawa. Y. Ruthenium-Catalyzed Olefin Cross-Metathesis with
Tetrafluoroethylene and Analogous Fluoroolefins. J. Am. Chem. Soc. 2015,
137, 7031−7034. (b) Li, L.; Ni, C.; Xie, Q.; Hu, M.; Wang, F.; Hu, J.
TMSCF
Aryloxy)tetrafluoroethylation, and Tetrafluoroethylation. Angew. Chem.
Int. Ed. 2017, 56, 9971 –9975.
3 2 2
as a Convenient Source of CF =CF for Pentafluoroethylation,
(
(10) A limited number of reports have focused on five-membered
nickelacycles generated via the oxidative cyclization of TFE and another
unsaturated compounds. see: (a) Cundy, C. S.; Green, M.; Stone, F. G. A.
Reactions of Low-Valent Metal Complexes with Fluorocarbons. Part XII.
Fluoro-Olefin Reactions of Zerovalent Nickel Complexes. J. Chem. Soc. A
1
970, 1647−1653. (b) Kaschube, W.; Schröder, W.; Pörschke, K. R.;
Angermund, K.; Krüger, C. Amin-Nickel-Komplexe VI. Synthese, Struktur
und Reaktivität von (tmeda)Ni(C ). J. Organomet. Chem. 1990, 389,
99–408. (c) Schröder, W.; Bonrath, W.; Pörschke, K. R. Synthese und
Reactivität von (2,6-iPr Ph-dad)Ni(C ). J. Organomet. Chem. 1991, 408,
2
F
4
(19) We also updated the information regarding the reactivity of the
7c
3
Ni(II) fluoride species, which are useful for the preparation of fluorinated
2
2
F
4
cyclic compounds. See the Supporting Information in details.
(20) Application of the stoichiometric reaction to a catalytic reaction was
conducted. However, even after optimization of reaction conditions, the
result was not so fruitful.
C25–C29. (d) Bennett, M. A.; Hockless, D. C. R.; Wenger, E. Generation
of (2,3-η)-Naphthalyne-Nickel(0) Complexes and Their Reactions with
Unsaturated Molecules. Organometallics 1995, 14, 2091–2101. (e) Bennett,
M. A.; Glewis, M.; Hockless, D. C. R.; Wenger, E. Successive Insertion of
Tetrafluoroethylene and CO and of Tetrafluoroethylene and Acetylenes into
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O
R
F
F F
F
O
R
cat. Ni(0)/PCy3
H
F
+
+
+
toluene, 100 ºC
F
H
F F
32 examples
up to 98% chemoselectivity
up to 83% isolated yield
O
R
F
F
Ni(0)
F
0
1
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H
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H
F
F
F
F
O
F
– Ni(0)
Ni
F
Ni
F
Ni
F
F
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