Rhodium(I)-catalyzed [2+2+2+2] cycloaddition of diynes to form cyclooctatetraenes

Article abstract of DOI:10.1002/ejoc.201402109

Unique reactivity of a rhodium catalyst in the presence of many different Lewis basic additives was observed and studied. In the absence of additives, it was observed that a selective [2+2+2] reaction to form benzene products occurred; however, in the presence of an additive, optimally DMSO, the first rhodium(I)-catalyzed [2+2+2+2] reaction of alkynes occurred. A screen of different additives and catalysts was performed. Finally, a brief mechanistic study performed by using a ReactIR determined that DMSO coordinates to the catalyst, which affects the energetics of the reaction pathway. This appears primarily to raise the transition-state energy for the reductive elimination to form the benzene products. The first rhodium(I)-catalyzed [2+2+2+2] cycloaddition of alkynes is reported. The typical cyclotrimerization of alkynes to form benzene rings is still observed, but it was found to be significantly impacted by additives. A series of additives and mechanistic studies, performed using a ReactIR, were used to determine that DMSO is an efficient ligand for the Rh^I catalyst to impact the reaction mechanism. Copyright

Full text of DOI:10.1002/ejoc.201402109

SHORT COMMUNICATION
DOI: 10.1002/ejoc.201402109
Rhodium(I)-Catalyzed [2+2+2+2] Cycloaddition of Diynes To Form
Cyclooctatetraenes
Daniel J. Nasrallah[a] and Mitchell P. Croatt*[a]
Keywords: Organometallics / Cycloaddition / Alkynes / Nickel / Rhodium
Unique reactivity of a rhodium catalyst in the presence of
many different Lewis basic additives was observed and
studied. In the absence of additives, it was observed that a
selective [2+2+2] reaction to form benzene products oc-
curred; however, in the presence of an additive, optimally
DMSO, the first rhodium(I)-catalyzed [2+2+2+2] reaction of
alkynes occurred. A screen of different additives and cata-
lysts was performed. Finally, a brief mechanistic study per-
formed by using a ReactIR determined that DMSO coordi-
nates to the catalyst, which affects the energetics of the reac-
tion pathway. This appears primarily to raise the transition-
state energy for the reductive elimination to form the benz-
ene products.
Introduction
a [2+2+2+2] reaction of four alkynes to form COTs has
only been previously reported by using nickel catalysts.[9]
During attempts to produce complex heterocycles 5 from
The ability to manipulate and convert basic chemical
feedstocks into complex and diverse structures is pivotal
to the continuing evolution of synthetic organic chemistry. diynes 1 and nitrosobenzene, it was discovered that COT 2
Organic chemists have the responsibility to design and de- was formed by a RhI catalyst, along with benzene byprod-
velop new reactions and processes to better learn and pre- ucts 3 and 4 (Scheme 1). The lack of literature reports for
dict reactivity. Transition-metal-catalyzed reactions play an producing COTs by using anything besides a nickel catalyst
important role, as they often convert simple starting materi- motivated the pursuit of this novel reaction. Given that ni-
als into complex products. For example, a variety of Ni0 trosobenzene was not incorporated into any isolable prod-
catalysts have been reported to convert four alkynes[1] or ucts that also contained the initial diyne, nitrosobenzene
two diynes[2] into cyclooctatetraenes (COTs), molecules of was removed from the reaction and a more rapid reaction
interest as building blocks for synthesis,[3] ligands for transi- took place (0.5 vs. 1.5 h to full consumption of the starting
tion metals,[4] and conducting polymers.[5] Usually ac- material). In the absence of nitrosobenzene, however, a se-
companying the production of COTs are benzene products lective synthesis of benzenes 3 and 4 through the typical
that result from [2+2+2] reactions. Although metal catalysts [2+2+2] reaction pathway occurred (Scheme 1). COT 2 was
are well known to react with diynes in [2+2+2] reactions to only observed with nitrosobenzene present, so it was
form benzene rings,[6] pyridines,[7] and other heterocycles,[8] envisioned that nitrosobenzene or some modified form of
Scheme 1. Initial discovery of a rhodium(I)-catalyzed [2+2+2+2] cycloaddition of tethered diynes to produce a cyclooctatetraene;
DCE = 1,2-dichloroethane.
[a] Department of Chemistry and Biochemistry, University of
North Carolina at Greensboro,
nitrosobenzene (see below) must facilitate the [2+2+2+2] re-
action pathway. This requirement of an additive for the rho-
dium(I)-catalyzed [2+2+2+2] cycloaddition could explain
the dearth of publications reporting this reactivity. Herein
is presented the first [2+2+2+2] reaction of alkynes to form
435 Sullivan Science Bldg., Greensboro, NC 27402, USA
E-mail: E-mail:mpcroatt@uncg.edu
http://www.uncg.edu/che/faculty/croatt/index.html
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201402109.
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D. J. Nasrallah, M. P. Croatt
SHORT COMMUNICATION
COTs by using a RhI catalyst, a process that is enabled by (DMSO), were more effective to selectively produce COT 2
the use of additives.
(Table 1, entries 8 and 9). It was previously reported that
DMSO can act as a ligand on transition metals to affect
reactivity and selectivities, and related sulfoxides have been
used in RhI-catalysis.[11] Notably, if the reactions were run
open to air (see the Supporting Information) or in the pres-
ence of water (Table 1, entry 7), conditions for which Ni0
catalysis is typically sensitive, COT 2 was still formed.
Different solvents were screened for the reaction, and it
was found that the best results occurred if the reactions
were run in either CDCl3 or THF (Table 1, entries 9–12).
Although the addition of a catalytic amount of DMSO was
beneficial to form COT 2, it was determined that the
amount of DMSO should be approximately equimolar to
the catalyst (Table 1, entries 9 and 12–14). With respect to
the mechanism of this reaction, it was found that the order
of addition was important for this reaction. If DMSO was
added after premixing of the diyne and catalyst, the selec-
tivity for COT 2 formation was decreased (Table 1, en-
try 15). Surprisingly, although an additive was required for
the formation of COT 2 under the original conditions
(Scheme 1), the absence of an additive under the conditions
of Table 1 led to the formation of a small, but not negligi-
ble, amount of COT 2 (Table 1, entry 16).
Results and Discussion
In the process of determining the structure of COT 2 and
benzene products 3 and 4,[6q] it was also discovered that
nitrosobenzene was converted into azoxybenzene during the
course of the reaction.[10] It appears that the conversion of
nitrosobenzene into azoxybenzene was potentially benefi-
cial, because if pure azoxybenzene was added in place of
nitrosobenzene, the molar ratio, as determined by analysis
1
of the crude mixture by H NMR spectroscopy, of COT 2
to benzenes 3 and 4 was improved (0.2:1 for nitrosobenzene
and 0.6:1 for azoxybenzene). This selectivity, however, was
lost if the reactions were run at 55 °C in CDCl3 (Table 1,
entries 1 and 2).
Table 1. Additive screening for synthesis of COT 2.[a]
Entry Additive (equiv.)
Solvent
2/(3&4)[b]
1
2
nitrosobenzene (0.1)
azoxybenzene (0.1)
CDCl3
CDCl3
CDCl3
0.3:1
0.2:1[c]
0.3:1
3
azobenzene (0.1)
4[d]
5
nitromethane (solvent, 0.04 m)
N,N-dimethylformamide (0.1)
1-dodecanethiol (0.1)
water/ethanol (0.5)
CH3NO2 0.4:1
After discovering the effect that DMSO had on the RhI-
catalyzed [2+2+2+2] cycloaddition to produce COTs, it was
desirable to investigate if there was an observable effect with
the use of RhI, Ni0, Pd0, RuII, or IrI catalysts (Table 2).[2a]
First, a series of RhI catalysts were examined for this reac-
tion (Table 2, entries 1–8) and the chlorocarbonyl dimer
CDCl3
CDCl3
CDCl3
CDCl3
CDCl3
THF
0.6:1[c]
6
7
Ͻ0.1:1
0.6:1
0.7:1
1.4:1
1.5:1
1.0:1
Ͻ0.1:1
1.0:1
1.3:1
0.8:1
0.4:1
8
9
methyl phenyl sulfoxide (0.1)
dimethyl sulfoxide (0.1)
dimethyl sulfoxide (0.1)
dimethyl sulfoxide (0.1)
10
11
12
13
14
15[e]
16
DCE
dimethyl sulfoxide (solvent, 0.1 m) DMSO
dimethyl sulfoxide (0.05)
dimethyl sulfoxide (0.2)
dimethyl sulfoxide (0.1)
no additive
CDCl3
CDCl3
CDCl3
CDCl3
Table 2. Catalyst screening for synthesis of COT 2.[a]
Entry Catalyst
2/(3&4)[b]
without
DMSO
with
DMSO
[a] Reaction conditions (unless otherwise indicated): Sequential ad-
dition of diyne (1 equiv.), solvent (0.1 m), additive (0.1 equiv.), and
[RhCl(CO)2]2 (0.05 equiv.). Reactions proceeded to 75% conver-
1
2
3
[RhCl(CO)2]2
[RhCl(CO)2]2, 2AgSbF6
[RhOH(cod)]2
0.4:1
1.4:1
0.3:1
0.2:1
1
sion after 2 d at 55 °C. [b] Determined by H NMR spectroscopy.
[c] Approximately 40–70% conversion. [d] Reaction was run at
room temperature. [e] DMSO was added 10 min after the addition
of the catalyst.
4
5
6
7
8
9
10
11
12
13
14
15
16
[RhCl(cod)]2
0.9:1
0.2:1
[RhCl(cod)]2, 2AgSbF6
[Rh(PPh3)2(CO)Cl]
[Rh(PPh3)2(CO)Cl], AgSbF6
[RhCl(CO)2]2/CO
Ͻ0.1:1
Ͻ0.1:1[c]
Ͻ0.1:1
5.9:1
Ͻ0.1:1
no reaction
1.0:1
no reaction
no reaction
no reaction
Ͻ0.1:1[c]
To explore what effects other additives had on the reac-
tion, a series of additives were screened (Table 1; a more
extensive table of additive screening is presented in the Sup-
porting Information). To better monitor the reactions, the
temperature was lowered from 80 to 55 °C. Additionally,
there was a negligible difference between DCE and CDCl3
so the reactions were also run in CDCl3 for ease in monitor-
ing and recording accurate ratios of COT 2 to benzene
products 3 and 4.
There were a few notable results of the screening of addi-
tives and solvents. First, compounds with nitrogen or oxy-
gen atoms similar to those in nitrosobenzene and azoxy-
benzene gave similar results (Table 1, entries 1–5). Second,
although thiols and alcohols were not as beneficial for the
synthesis of COT 2 (Table 1, entries 6 and 7), it was deter-
[d]
Ni(dme)Br2
5.6:1
[e]
NiCl2(PPh3)2
Ͻ0.1:1[c]
no reaction
1.2:1
[f]
Ni(cod)2[f, g]
Ni(cod)2
Pd(PPh3)4
[RuCl2(p-cymene)]2
[IrCl(cod)]2
[IrCl(cod)]2, 2AgSbF6
[a] Reaction conditions (unless otherwise indicated): Sequential ad-
dition of diyne (1 equiv.), CDCl3 (0.1 m), DMSO (0.1 equiv.), cata-
lyst (0.05 equiv.), and co-catalyst (0.1 equiv.) if indicated. Reaction
proceeded to 60% conversion after 2 d at 55 °C; cod = 1,5-cyclo-
octadiene, DME
= 1,2-dimethoxyethane. [b] Determined by
1H NMR spectroscopy. [c] Approximately 30–50% conversion.
[d] In THF (0.1 m), catalyst (20 mol-%), Zn (40 mol-%), H2O
(20 mol-%), 55 °C, 7 h. [e] In THF (0.1 m), catalyst (20 mol-%), Zn
(40 mol-%), H2O (20 mol-%), 55 °C, 5 h. [f] Run in the glove box,
mined that sulfoxides, particularly dimethyl sulfoxide room temperature. [g] In THF (0.1 m), catalyst (20 mol-%), 1 h.
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Rhodium(I)-Catalyzed [2+2+2+2] Cycloaddition of Diynes
was found to be the most selective in the presence of DMSO
To better understand the role that DMSO played in the
(Table 2, entry 1). Interestingly, if an atmosphere of carbon reaction, a series of experiments were run and monitored
monoxide was added, the reaction produced a negligible by using in situ IR spectroscopy to obtain real-time infor-
amount of COT 2 (Table 2, entry 8). This indicated that mation on the reactions. Experiments were set up by using
DMSO might replace CO on the catalyst. As mentioned a ReactIR to monitor the presence of the starting material,
previously, a series of papers by the Wender group showed catalyst, additive, and products. In two separate experi-
that Ni0 catalysts, used directly or reduced in situ, are ments, the order of addition of DMSO and the diyne into
highly selective for the formation of COTs.[2a] We observed a solution of the RhI catalyst in CDCl3 was varied, as this
similar results and found no effect of DMSO on these Ni0- was found to be impactful on the selectivity of the reaction
catalyzed reactions (Table 2, entries 9–12). Notably, the re- (Table 1, entry 9 vs. 15). If DMSO was added to a solution
action with the NiII precatalyst with in situ reduction could of the catalyst prior to the diyne, there was a steep re-
be run outside the glove box, whereas the Ni(cod)2 catalyst duction in the intensity of the catalyst band (Figure 1, a).
rapidly degraded outside of the glove box, presumably by If the diyne was then added to the solution of catalyst and
trace amounts of oxygen. The other catalysts screened did DMSO, there was a gradual decrease in the remaining cata-
not produce any COTs and typically resulted in little to no lyst band. However, if the order was reversed and DMSO
reaction of the starting diyne (Table 2, entries 13–16).
was added after the diyne, the IR stretch associated with
Figure 1. (a) ReactIR trend lines of the catalyst (blue line, 2038 cm–1) added at ca. 9 min, DMSO (green line, 1016 cm–1) added at ca.
28 min, and diyne (red line, 1743 cm–1) added at ca. 39 min. (b) ReactIR trend lines of the catalyst added at ca. 5 min, diyne added at
ca. 11 min, and DMSO added at ca. 18 min (same colors and wavelengths as in a).
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D. J. Nasrallah, M. P. Croatt
SHORT COMMUNICATION
the catalyst steeply decreased in intensity for the addition ond alkyne insertion to occur (C to D) instead of reductive
of each sequential reagent (Figure 1, b). This indicates that elimination to yield benzene products 3 and 4. It was ob-
DMSO coordinates the catalyst and affects subsequent re- served that the consumption of the starting material was
activity. Additional ReactIR experiments were also in align- slower in the presence of DMSO, so it appears that DMSO
ment with the preferential and impactful coordination of increases the activation barrier for the reductive elimination
DMSO to the catalyst (see the Supporting Information).
mechanism is proposed for this RhI-catalyzed the energy barriers for the second alkyne insertion and later
[2+2+2+2] cycloaddition to produce COTs (Figure 2). The reductive elimination are also affected.
step to form the benzene products. It is also possible that
A
mechanism involves the oxidative cyclization of the rho-
During a brief exploration of the scope of the RhI-cata-
dium catalyst, followed by alkyne coordination. Rhodacy- lyzed [2+2+2+2] reaction (Scheme 2), this catalytic pathway
clopentadiene B inserts the alkyne to yield rhodacyclohep- was found to have a reactivity pattern similar to that of the
tatriene C. Intermediate C can either reductively eliminate Ni0-catalyzed pathway.[2] For example, sulfonamide-teth-
to produce the benzene byproducts or undergo an ad- ered diyne 6 reacted smoothly to yield COT 7 and benzenes
ditional alkyne insertion to form rhodacyclononatetraene 8 and 9 in a ratio similar to that obtained with malonate-
D. Metallacycle D then undergoes reductive elimination to tethered diyne 1 (compare Scheme 2 with Table 1, entry 9).
produce COT 2 and to regenerate the RhI catalyst. The Substrate 10 with internal alkynes, however, did not yield
presence of an additive, optimally DMSO, enables the sec- COT product 11.
Figure 2. Proposed mechanism for the rhodium(I)-catalyzed [2+2+2+2] cycloaddition of tethered diynes.
Scheme 2. Reactivity of additional diynes; Ts = p-tolylsulfonyl.
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Eur. J. Org. Chem. 2014, 3767–3772

Rhodium(I)-Catalyzed [2+2+2+2] Cycloaddition of Diynes
Conclusions
Acknowledgments
In summary, a rhodium(I)-catalyzed [2+2+2+2] cycload-
dition of alkynes to produce COTs, preferentially enabled
by the addition of DMSO, was reported. This is the first
reaction of its kind that is not catalyzed by Ni0. The meth-
odology is a missing link of reactivity for RhI and Ni0 cata-
lysts with diynes, as both metal catalysts were known to
undergo [2+2+2] cycloadditions to form benzene rings but
previously only Ni0 was reported to construct COTs
through a [2+2+2+2] reaction. A series of additives and cat-
alysts were screened with this reaction, and it was found
that DMSO, in a catalytic amount, was optimal for the RhI
catalysts, but it was ineffective for Ni0 catalysts. The reac-
tions were studied by using ReactIR instrumentation, and
it was proposed that DMSO coordinates the rhodium cata-
lyst and affects the reductive elimination (vs. ring expan-
sion) pathways of the two mechanistic options.
Funding for this project from The University of North Carolina at
Greensboro in the form of a New Faculty Grant (to M. P. C.) and
a Summer Research Fellowship (to M. P. C.) and from the George
T. Barthalmus Undergraduate Research Grant (to D. J. N.) and the
Barry M. Goldwater Scholarship (to D. J. N.) are gratefully
acknowledged. The authors thank Dr. Franklin J. Moy (UNCG)
for assisting with analysis of the NMR spectroscopic data.
[1] a) W. Reppe, O. Schlichting, K. Klager, T. Toepel, Justus Lie-
bigs Ann. Chem. 1948, 560, 1–92; b) T. R. Boussie, A. Streit-
wieser, J. Org. Chem. 1993, 58, 2377–2380; c) R. E. Colborn,
K. P. C. Vollhardt, J. Am. Chem. Soc. 1986, 108, 5470–5477; d)
C. J. Lawrie, K. P. Gable, B. K. Carpenter, Organometallics
1989, 8, 2274–2276.
[2] a) P. A. Wender, J. P. Christy, J. Am. Chem. Soc. 2007, 129,
13402–13403; b) P. A. Wender, J. P. Christy, A. B. Lesser, M. T.
Gieseler, Angew. Chem. Int. Ed. 2009, 48, 7687–7690; Angew.
Chem. 2009, 121, 7823–7826; c) F. Wagner, H. Meier, Tetrahe-
dron 1974, 30, 773–780; d) G. Chiusoli, L. Pallini, M. Terenghi,
Trans. Met. Chem. 1985, 10, 350–351; e) A. Goswami, T. Ito,
N. Saino, K. Kase, C. Matsuno, S. Okamoto, Chem. Commun.
2009, 439–441.
Experimental Section
[3] a) I. Ernest, Angew. Chem. Int. Ed. Engl. 1976, 15, 207–214;
Angew. Chem. 1976, 88, 244–252; b) L. Kelebekli, M. Çelik, E.
General Procedure: The catalyst (5 mol-%) was added to a solution
of dimethyl sulfoxide (10 mol-%) if indicated and the diyne (50 mg,
1 equiv.) in CDCl3 (0.1 m) under an atmosphere of N2, and the
solution was warmed to 55 °C. After 2 d, the solution was cooled
to ambient temperature and analysis by NMR spectroscopy was
directly performed (see Tables 1 and 2 and Scheme 2).
Sahin, Y. Kara, M. Balci, Tetrahedron Lett. 2006, 47, 7031–
¸
7035; c) L. Kelebekli, Y. Kara, M. Balci, Carbohydr. Res. 2005,
340, 1940–1948.
[4] P. A. Wender, A. B. Lesser, L. E. Sirois, Angew. Chem. Int. Ed.
2012, 51, 2736–2740; Angew. Chem. 2012, 124, 2790–2794.
[5] O. A. Scherman, I. M. Rutenberg, R. H. Grubbs, J. Am. Chem.
Soc. 2003, 125, 8515–8522.
Nickel Reactions with Zinc: Dimethyl sulfoxide (6.8 μL,
0.096 mmol) if indicated was added to a solution of the diyne
(50 mg, 0.24 mmol), zinc powder (6.27 mg, 0.096 mmol), water
(0.86 μL, 0.048 mmol), and THF (2.4 mL, 0.1 m) followed by the
catalyst (0.048 mmol) under an atmosphere of N2, and the solution
was warmed to 55 °C. After the time indicated, the solution was
cooled to ambient temperature and concentrated under reduced
pressure. The residue was dissolved in CDCl3 and analysis by NMR
spectroscopy was performed (see Table 2, entries 9 and 10).
[6] For the synthesis of structures in this publication and recent
reports of similar reactions, see: a) B. Witulski, T. Stengel, An-
gew. Chem. Int. Ed. 1999, 38, 2426–2430; Angew. Chem. 1999,
111, 2521–2524; b) F. E. McDonald, H. Y. H. Zhu, C. R.
Holmquist, J. Am. Chem. Soc. 1995, 117, 6605–6606; c) I.
Ojima, A. T. Vu, J. V. McCullagh, A. Kinoshita, J. Am. Chem.
Soc. 1999, 121, 3230–3231; d) C. Xi, Z. Sun, Y. Liu, Dalton
Trans. 2013, 42, 13327–13330; e) T. Araki, K. Noguchi, K.
Tanaka, Angew. Chem. Int. Ed. 2013, 52, 5617–5621; Angew.
Chem. 2013, 125, 5727–5731; f) I. Thiel, H. Jiao, A. Spannen-
berg, M. Hapke, Chem. Eur. J. 2013, 19, 2548–2554; g) L. Xu,
R. Yu, Y. Wang, J. Chen, Z. Yang, J. Org. Chem. 2013, 78,
5744–5750; h) A.-L. Auvinet, V. Michelet, V. Ratovelomanana-
Vidal, Synthesis 2013, 45, 2003–2008; i) K. Murayama, Y. Sa-
wada, K. Noguchi, K. Tanaka, J. Org. Chem. 2013, 78, 6202–
6210; j) K. Geetharani, S. Tussupbayev, J. Borowka, M. C.
Holthausen, S. Ghosh, Chem. Eur. J. 2012, 18, 8482–8489; k)
M. Parera, A. Dachs, M. Solà, A. Pla-Quintana, A. Roglans,
Chem. Eur. J. 2012, 18, 13097–13107; l) T. Shibata, M. Miyoshi,
T. Uchiyama, K. Endo, N. Miura, K. Monde, Tetrahedron
2012, 68, 2679–2686; m) J. M. Batson, T. M. Swager, ACS
Macro Lett. 2012, 1, 1121–1123; n) Y.-k. Sugiyama, T. Kariwa,
T. Sakurada, S. Okamoto, Synlett 2012, 23, 2549–2553; o) S.
Brun, A. Torrent, A. Pla-Quintana, A. Roglans, X. Fontro-
dona, J. Benet-Buchholz, T. Parella, Organometallics 2012, 31,
318–326; p) N. Saito, T. Ichimaru, Y. Sato, Org. Lett. 2012, 14,
1914–1917; q) S. Kezuka, S. Tanaka, T. Ohe, Y. Nakaya, R.
Takeuchi, J. Org. Chem. 2006, 71, 543–552.
Nickel Reactions in Glove Box: The diyne (50 mg, 0.24 mmol) was
added to a solution of dimethyl sulfoxide (1.7 μL, 0.024 mmol) if
indicated and CDCl3 or THF (2.4 mL, 0.1 m). This solution was
flushed with N2, and the vessel was sealed and transferred to a
glove box under a N2 atmosphere. Ni(cod)2 (3.3 mg, 0.012 mmol)
was added, and the solution was stirred at ambient temperature.
After 1 h, the solution was taken out of the glove box and evapo-
rated under reduced pressure. The residue was dissolved in CDCl3,
and analysis by NMR spectroscopy was performed (see Table 2,
entries 11 and 12).
General Procedure for the ReactIR Experiments: Dimethyl sulfoxide
(20 μL, 0.24 mmol), the diyne (100 mg, 0.48 mmol), and
[RhCl(CO)2]2 (46.6 mg, 0.12 mmol) were added to CDCl3 (4.8 mL,
0.1 m) at ambient temperature under an atmosphere of N2. The
order and time of addition is reported with each experiment (see
the Supporting Information). The reaction was monitored by
ReactIR. After 1 d, analysis by NMR spectroscopy was performed.
[7] For recent reports, see: a) R. M. Stolley, H. A. Duong, J. Louie,
Organometallics 2013, 32, 4952–4960; b) F. Xu, C. Wang, D.
Wang, X. Li, B. Wan, Chem. Eur. J. 2013, 19, 2252–2255; c) F.
Fischer, P. Jungk, N. Weding, A. Spannenberg, H. Ott, M.
Hapke, Eur. J. Org. Chem. 2012, 5828–5838; d) S. Medina, G.
Domínguez, J. Pérez-Castells, Org. Lett. 2012, 14, 4982–4985;
e) R. M. Stolley, H. A. Duong, D. R. Thomas, J. Louie, J. Am.
Chem. Soc. 2012, 134, 15154–15162; f) G. Onodera, Y. Shimizu,
Supporting Information (see footnote on the first page of this arti-
cle): General information, full table of additive screening, 1H NMR
spectra of compounds and determination of relative ratios, solu-
tion-state ReactIR spectra, and full listing of reactions monitored
by ReactIR.
Eur. J. Org. Chem. 2014, 3767–3772
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SHORT COMMUNICATION
J.-n. Kimura, J. Kobayashi, Y. Ebihara, K. Kondo, K. Sakata,
R. Takeuchi, J. Am. Chem. Soc. 2012, 134, 10515–10531; g) F.
Xu, C. Wang, X. Li, B. Wan, ChemSusChem 2012, 5, 854–857;
h) P. Garcia, Y. Evanno, P. George, M. Sevrin, G. Ricci, M.
Malacria, C. Aubert, V. Gandon, Chem. Eur. J. 2012, 18, 4337–
4344; i) P. Kumar, S. Prescher, J. Louie, Angew. Chem. Int. Ed.
2011, 50, 10694–10698; Angew. Chem. 2011, 123, 10882–10886;
j) N. Weding, R. Jackstell, H. Jiao, A. Spannenberg, M. Hapke,
Adv. Synth. Catal. 2011, 353, 3423–3433; k) Y.-k. Sugiyama, S.
Okamoto, Synthesis 2011, 2247–2254; l) C. Wang, X. Li, F.
Wu, B. Wan, Angew. Chem. Int. Ed. 2011, 50, 7162–7166; An-
gew. Chem. 2011, 123, 7300–7304; m) Y. Zou, Q. Liu, A. Deit-
ers, Org. Lett. 2011, 13, 4352–4355; n) B. R. D’Souza, T. K.
Lane, J. Louie, Org. Lett. 2011, 13, 2936–2939; o) Y. Satoh, Y.
Obora, J. Org. Chem. 2013, 78, 7771–7776; p) C. Wang, D.
Wang, F. Xu, B. Pan, B. Wan, J. Org. Chem. 2013, 78, 3065–
3072.
Aubert, J. Am. Chem. Soc. 2013, 135, 4576–4579; d) G. Onod-
era, M. Suto, R. Takeuchi, J. Org. Chem. 2012, 77, 908–920.
For interesting examples of the use of RhI catalysts to perform
a series of [2+2+2] reactions, in which a centralized COT is
formed, see: a) T. Shibata, T. Chiba, H. Hirashima, Y. Ueno,
K. Endo, Angew. Chem. Int. Ed. 2009, 48, 8066–8069; Angew.
Chem. 2009, 121, 8210–8213; b) T. Shibata, M. Fujimoto, H.
Hirashima, T. Chiba, K. Endo, Synthesis 2012, 44, 3269–3284;
for an example of a RhI-catalyzed [2+2+2+2] reaction involv-
ing four alkenes, see: c) P. A. Wender, M. P. Croatt, B. Kühn,
Organometallics 2009, 28, 5841–5844.
[9]
[10]
Y. Mugnier, J. C. Gard, Y. Huang, Y. Couture, A. Lasia, J. Les-
sard, J. Org. Chem. 1993, 58, 5329–5334.
[11] a) M. S. Chen, M. C. White, J. Am. Chem. Soc. 2004, 126,
1346–1347; b) R. Mariz, A. Poater, M. Gatti, E. Drinkel, J. J.
Bürgi, X. Luan, S. Blumentritt, A. Linden, L. Cavallo, R.
Dorta, Chem. Eur. J. 2010, 16, 14335–14347; c) J. J. Bürgi, R.
Mariz, M. Gatti, E. Drinkel, X. Luan, S. Blumentritt, A. Lin-
den, R. Dorta, Angew. Chem. Int. Ed. 2009, 48, 2768–2771;
Angew. Chem. 2009, 121, 2806–2809.
[8] For recent reports, see: a) S. Alvarez, S. Medina, G. Domíng-
uez, J. Pérez-Castells, J. Org. Chem. 2013, 78, 9995–10001; b)
M. Auge, M. Barbazanges, A. T. Tran, A. Simonneau, P. Elley,
H. Amouri, C. Aubert, L. Fensterbank, V. Gandon, M. Malac-
ria, J. Moussa, C. Ollivier, Chem. Commun. 2013, 49, 7833–
7835; c) M. Amatore, D. Lebœuf, M. Malacria, V. Gandon, C.
Received: February 19, 2014
Published Online: May 9, 2014
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