Rhodium-catalyzed direct alkenylation and arylation of arene C-H bonds via decarbonylation of cinnamoyl chlorides, cinnamic anhydrides, and poly(aroyl) chlorides

Article abstract of DOI:10.1021/om900997y

Efficient regioselective direct alkenylation of benzo[h]quinoline was realized with cinnamoyl chlorides as the coupling partners via decarbonylation of the chlorides and C-H bond activation by means of [Rh(CO)₂Cl] ₂ as the catalyst i

Full text of DOI:10.1021/om900997y

Organometallics 2010, 29, 1049–1052 1049
DOI: 10.1021/om900997y
Rhodium-Catalyzed Direct Alkenylation and Arylation of Arene C-H
Bonds via Decarbonylation of Cinnamoyl Chlorides,
Cinnamic Anhydrides, and Poly(aroyl) Chlorides
Wenjing Ye,† Ning Luo,† and Zhengkun Yu*,†,‡
†Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning
116023, People’s Republic of China and ‡State Key Laboratory of Organometallic Chemistry, Shanghai
Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, People’s
Republic of China
Received November 16, 2009
Summary: Efficient regioselective direct alkenylation of
benzo[h]quinoline was realized with cinnamoyl chlorides as
the coupling partners via decarbonylation of the chlorides and
C-H bond activation by means of [Rh(CO)2Cl]2 as the
catalyst in refluxing o-xylene under phosphine-free conditions.
For 2-phenylpyridine, [Rh(CO)2Cl]2 or [Rh(COD)Cl]2 effi-
ciently promoted its direct alkenylation with cinnamic anhy-
drides. Polyarenes were synthesized from [Rh(COD)Cl]2-
catalyzed decarbonylative poly(arylation) of isophthaloyl
dichloride, terephthaloyl dichloride, or benzene-1,3,5-tricar-
bonyl chloride with benzo[h]quinoline.
of arene C-H bonds has become more and more attractive
for construction of carbon-carbon bonds.3 Chelation-as-
sisted functionalization of arenes via C-H bond activation
by using a directing group such as carbonyl,4 imino,5 amino,6
and pyridyl7 has been paid much attention due to the high
regioselectivity of the desired products. Although a lot of
examples of direct arylation of arenes have been documented,
direct alkenylation of arenes has not received considerable
attention. So far, chelation-assisted C-H functionalization
of arenes with alkenylboron reagents,8 alkenes,9 alkynes,10
alkyl acrylates,11 and alkenyl acetates12 has been reported for
this purpose. A variety of coupling partners were successfully
explored, but they have been applied in C-H functionaliza-
tion with limitations.1,13 As potential coupling compounds,
acid chlorides were used for carbon-carbon couplings under
controlled conditions.7c,e,f,14 Although carboxylic acids can
be decarbonylatively transformed by transition metals,15
only a few examples have been scattered.16 Recently,
we found that aroyl chlorides and benzoic and cinnamic
anhydrides can be used as decarbonylative coupling partners
Introduction
Alkenylation is a useful synthetic protocol to prepare
functional materials, natural products, and bioactive mole-
cules.1,2 Recently, transition-metal-catalyzed functionalization
*Corresponding author. E-mail: zkyu@dicp.ac.cn.
(1) For selected recent reviews, see: (a) Denmark, S. E.; Butler, C. R.
Chem. Commun. 2009, 20. (b) Negishi, E.-I.; Huang, Z. H.; Wang, G. W.;
Mohan, S.; Wang, C.; Hattori, H. Acc. Chem. Res. 2008, 41, 1474.
(2) (a) Hoeben, F. J. M.; Jonkheijm, P.; Meijer, E. W.; Schenning,
A. P. H. J. Chem. Rev. 2005, 105, 1491. (b) Wu, J. L.; Cui, X. L.; Chen, L.
M.; Jiang, G. J.; Wu, Y. J. J. Am. Chem. Soc. 2009, 131, 13888. (c) Katagiri,
T.; Mukai, T.; Satoh, T.; Hirano, K.; Miura, M. Chem. Lett. 2009, 38, 118.
(3) For selected recent reviews, see: (a) Alberico, D.; Scott, M. E.;
Lautens, M. Chem. Rev. 2007, 107, 174. (b) Lewis, J. C.; Bergman, R. G.;
Ellman, J. A. Acc. Chem. Res. 2008, 41, 1013. (c) McGlacken, G. P.;
Bateman, L. M. Chem. Soc. Rev. 2009, 38, 2447. (d) Chen, X.; Engle, K. M.;
Wang, D.-H.; Yu, J.-Q. Angew. Chem., Int. Ed. 2009, 48, 5094.
(8) (a) Ueno, S.; Chatani, N.; Kakiuchi, F. J. Org. Chem. 2007, 72,
3600. (b) Ueno, S.; Kochi, T.; Chatani, N.; Kakiuchi, F. Org. Lett. 2009, 11,
855.
(9) (a) Umeda, N.; Hirano, K.; Satoh, T.; Miura, M. J. Org. Chem.
2009, 74, 7094. (b) Trost, B. M.; Thaisrivongs, D. A. J. Am. Chem. Soc.
2008, 130, 14092. (c) Khenkin, A. M.; Neumann, R. J. Am. Chem. Soc.
2008, 130, 11876.
(10) (a) Shibata, Y.; Otake, Y.; Hirano, M.; Tanaka, K. Org. Lett.
2009, 11, 689. (b) Tsuchikama, K.; Kasagawa, M.; Endo, K.; Shibata, T. Org.
Lett. 2009, 11, 1821. (c) Mukai, T.; Hirano, K.; Satoh, T.; Miura, M. J. Org.
Chem. 2009, 74, 6410. (d) Rodriguez, A.; Fennessy, R. V.; Moran, W. J.
Tetrahedron Lett. 2009, 50, 3942. (e) Li, L.; Brennessel, W. W.; Jones, W. D.
J. Am. Chem. Soc. 2008, 130, 12414. (f) Nakao, Y.; Kanyiva, K. S.; Hiyama,
T. J. Am. Chem. Soc. 2008, 130, 2448. (g) Cheng, K.; Yao, B. B.; Zhao, J. L.;
Zhang, Y. H. Org. Lett. 2008, 10, 5309. (h) Sun, Z. K.; Yu, S. Y.; Ding, Z. D.;
Ma, D. W. J. Am. Chem. Soc. 2007, 129, 9300. (i) Kanyiva, K. S.; Nakao, Y.;
Hiyama, T. Angew. Chem., Int. Ed. 2007, 46, 8872.
(4) For selected recent reports, see: (a) Wang, D.-H.; Mei, T.-S.; Yu,
J.-Q. J. Am. Chem. Soc. 2008, 130, 17676. (b) Inoue, S.; Shiota, H.;
Fukumoto, Y.; Chatani, N. J. Am. Chem. Soc. 2009, 131, 6898. (c) Martinez,
R.; Simon, M.-O.; Chevalier, R.; Pautigny, C.; Genet, J.-P.; Darses, S. J. Am.
Chem. Soc. 2009, 131, 7887. (d) Jia, Y.-X.; K€undig, E. P. Angew. Chem., Int.
Ed. 2009, 48, 1636. (e) Houlden, C. E.; Hutchby, M.; Bailey, C. D.; Ford,
ꢀ
J. G.; Tyler, S. N. G.; Gagne, M. R.; Lloyd-Jones, G. C.; Booker-Milburn, K.
ꢀ
(11) (a) Garcıa-Rubia, A.; Arrayas, R. G.; Carretero, J. C. Angew.
´
I. Angew. Chem., Int. Ed. 2009, 48, 1830. (f) Zhou, H.; Xu, Y.-H.; Chung,
W.-J.; Loh, T.-P. Angew. Chem., Int. Ed. 2009, 48, 5355. (g) Zhou, H.;
Chung, W.-J.; Xu, Y.-H.; Loh, T.-P. Chem. Commun. 2009, 3472.
(5) (a) Ackermann, L. Org. Lett. 2005, 7, 3123. (b) Yoshikai, N.;
Matsumoto, A.; Norinder, J.; Nakamura, E. Angew. Chem., Int. Ed. 2009,
48, 2925.
Chem., Int. Ed. 2009, 48, 6511. (b) Cho, S. H.; Hwang, S. J.; Chang, S.
J. Am. Chem. Soc. 2008, 130, 9254. (c) Beck, E. M.; Hatley, R.; Gaunt, M. J.
Angew. Chem., Int. Ed. 2008, 47, 3004. (d) Cai, G. X.; Fu, Y.; Li, Y. Z.; Wan,
X. B.; Shi, Z. J. J. Am. Chem. Soc. 2007, 129, 7666. (e) Zaitsev, V. G.;
Daugulis, O. J. Am. Chem. Soc. 2005, 127, 4156.
(6) He, H.; Liu, W.-B.; Dai, L.-X.; You, S.-L. J. Am. Chem. Soc. 2009,
131, 8346.
(12) Matsuura, Y.; Tamura, M.; Kochi, T.; Sato, M.; Chatani, N.;
Kakiuchi, F. J. Am. Chem. Soc. 2007, 129, 9858.
(13) Desai, L. V.; Stowers, K. J.; Sanford, M. S. J. Am. Chem. Soc.
2008, 130, 13285.
(7) Selected recent reports, see: (a) Oi, S.; Aizawa, E.; Ogino, Y.;
Inoue, Y. J. Org. Chem. 2005, 70, 3113. (b) Ackermann, L.; Althammer, A.;
Born, R. Angew. Chem., Int. Ed. 2006, 45, 2619. (c) Zhao, X. D.; Yu, Z. K. J.
Am. Chem. Soc. 2008, 130, 8136. (d) Gu, S. J.; Chen, C.; Chen, W. Z. J. Org.
Chem. 2009, 74, 7203. (e) Kochi, T.; Urano, S.; Seki, H.; Mizushima, E.;
Sato, M.; Kakiuchi, F. J. Am. Chem. Soc. 2009, 131, 2792. (f) Zhao, X. D.;
(14) (a) Iwai, T.; Fujihara, T.; Terao, J.; Tsuji, Y. J. Am. Chem. Soc.
2009, 131, 6668. (b) Sugihara, T.; Satoh, T.; Miura, M.; Nomura, M. Angew.
Chem., Int. Ed. 2003, 42, 4672.
ꢀ
(15) Goossen, L. J.; Goossen, K.; Rodrrguez, N.; Blanchot, M.;
ꢀ
Dimitrijevic, E.; Dong, V. M. J. Am. Chem. Soc. 2009, 131, 3466.
Linder, C.; Zimmermann, B. Pure Appl. Chem. 2008, 80, 1725.
r
2010 American Chemical Society
Published on Web 01/28/2010
pubs.acs.org/Organometallics

1050 Organometallics, Vol. 29, No. 4, 2010
Ye et al.
Table 1. Screening of Reaction Conditionsa
Table 2. Direct Alkenylation of 1 via Decarbonylation of the
Substituted Cinnamoyl Chlorides (2) and C-H Bond Activationa
conversionc
(%)
entry 1:2ab
catalyst
base (equiv)
solvent
entry
R
product
yieldb (%)
1
2
3
4
5
6
7
8
1:1.5 [RhCl(COD)]2 Na2CO3 (2.0) o-xylene
1:1.5 [RhCl(CO)2]2d Na2CO3 (2.0) o-xylene
91
95
86
61
56
53
68
72
<1
14
90
24
1
2
3
4
5
6
7
8
Ph (2a)
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
77
77
65
69
30
55
53
76
77
43
60
47
55
52
2-MeC6H4 (2b)
3-MeC6H4 (2c)
4-MeC6H4 (2d)
2-MeOC6H4 (2e)
3-MeOC6H4 (2f)
4-MeOC6H4 (2g)c
4-FC6H4 (2h)
4-ClC6H4 (2i)
4-BrC6H4 (2j)
3-CF3C6H4 (2k)
2-naphthyl (2l)
2-furyl (2m)
1:1.5 [RhCl(CO)2]2
1:1.5 Rh(COD)2BF4 Na2CO3 (2.0) o-xylene
Na2CO3 (2.0) o-xylene
1:1.5 RhCl(PPh)3
1:1.5 [RhCl(CO)2]2
1:1.5 [RhCl(CO)2]2
1:1.5 [RhCl(CO)2]2
1:1.5 [RhCl(CO)2]2
1:2.0 [RhCl(CO)2]2
1:1.5 [RhCl(CO)2]2
1:1.5 [RhCl(CO)2]2
1:1.5 [RhCl(CO)2]2
1:2.0 [RhCl(CO)2]2
1:3.0 [RhCl(CO)2]2
Na2CO3 (2.0) o-xylene
K3PO4 (2.0) o-xylene
K2CO3 (2.0.) o-xylene
KF (2.0) o-xylene
Cs2CO3 (2.0) o-xylene
DBU (2.5) o-xylene
9
9
10
11
12
13
14
15
10
11
12
13
14
Na2CO3 (2.0) toluenee
Na2CO3 (2.0) DMF
Na2CO3 (2.0) NMP
Na2CO3 (2.0) o-xylene
Na2CO3 (3.5) o-xylene
0
97 (74)f
99 (77)f,g
2-thiophenyl (2n)
a Conditions: 1, 0.5 mmol; 2, 1.5 mmol; [Rh(CO)2Cl]2, 5 mol %;
Na2CO3, 3.5 equiv; 4 A molecular sieves; o-xylene, 5 mL; 145 °C, 24 h.
b Isolated yields. c 2, 2.0 equiv; Na2CO3, 3.0 equiv.
a Conditions: 1, 0.5 mmol; catalyst, 5 mol %; base, 2.0-3.5 equiv; 4 A
molecular sieves; solvent, 5 mL; 145 °C, 16 h. b Molar ratio of 1 to 2a.
c Determined by GC analysis. d 2.5 mol % catalyst. e 110 °C. f Isolated
yields in parentheses. g 24 h.
organic base DBU acted less effectively than Na2CO3
(entries 6-10). In refluxing toluene at 110 °C, the reaction
proceeded slowly (entry 11). In strong polar solvents
such as DMF and NMP the reaction proceeded very
slowly or no reaction occurred (entries 12 and 13). As
expected, increasing the amount of the coupling partner 2a
from 1.5 to 2 or 3 equiv, the conversion of 1 approached
97-99% and the desired product 3a could be isolated
in 74-77% yields (entries 14 and 15). Thus, the reaction
conditions were optimized to the following: molar ratio
of 1:2a = 1:3, 5 mol % [RhCl(CO)2]2 as the catalyst,
Na2CO3 as the base, 4 A MS as the promoter, in refluxing
o-xylene, and reaction time 24 h. It should be noted
that alkenylation of 1 with 2a is less efficient than the
arylation of 1 with benzoyl chlorides7c under the same
conditions.
Next, the direct alkenylation of 1 with substituted cinna-
moyl chlorides was carried out under the optimized con-
ditions to probe the protocol generality (eq 2, Table 2).
With 2-, 3-, or 4-methyl as the substituent in the aryl moiety
of a cinnamoyl chloride substrate, the target products
3b-d were obtained in 65-77% yields (entries 2-4).
A 2-methoxy substituent in 2e led to a low yield (30%) for
3e. With 3- or 4-methoxy as the substituent in 2f or 2g,
compounds 3f and 3g were isolated in moderate yields
(53-55%). The yields of the products 3h-k from the
reactions of 1 with electron-withdrawing substituent-
bearing cinnamoyl chlorides, i.e., 2h-k, varied from 43%
to 77% (entries 8-11). The naphthyl substituent presum-
ably increased the steric hindrance, and thus the reac-
tion of 2l produced 3l in only moderate yield (47%)
(entry 12). From the reactions of 1 with furyl- and thio-
phenyl-substituted acryloyl chlorides 2m and 2n the target
products 3m and 3n could be formed in good yields
(52-55%), respectively (entries 13 and 14). The same
protocol was also applied in the alkenylation of 2-aryl-
pyridines (4a-c) with cinnamoyl chloride (2a) (eq 3).
in [Rh(COD)Cl]2-catalyzed direct functionalization of are-
nes under phosphine-free conditions.7c,17 Herein, we report
[Rh(CO)2Cl]2- and [Rh(COD)Cl]2-catalyzed direct alkenyla-
tion of arene C-H bonds via decarbonylation of cinnamoyl
chlorides and substituted cinnamic anhydrides as well as
synthesis of polyarenes from poly(aroyl) chlorides.
Results and Discussion
In our initial studies, the Rh(I)-catalyzed reaction of
benzo[h]quinoline (1) with cinnamoyl chloride (2a) was
carried out in o-xylene at 145 °C under nitrogen atmo-
sphere to screen the reaction conditions (eq 1 and Table 1).
Under the conditions employed for C-H functionaliza-
tion of arenes with [RhCl(COD)]2 as the catalyst and aroyl
chlorides as the coupling partners,7c catalyst [RhCl(CO)2]2
exhibited a higher catalytic activity than [RhCl(COD)]2
for the reaction shown in eq 1 (Table 1, enties 1 and 2).
As we investigated before,7c 4 A molecular sieves acceler-
ated the reaction. Decreasing the loading of [RhCl(CO)2]2
from 5 mol % to 2.5 mol % led to a lower reaction
efficiency (entry 3). Rh(COD)2BF4 and Wilkinson’s cata-
lyst RhCl(PPh)3 showed much lower catalytic activity than
[RhCl(CO)2]2 under the same conditions (entries 4 and 5).
Inorganic bases K3PO4, K2CO3, KF, and Cs2CO3 and the
(16) (a) Kajita, Y.; Kurahashi, T.; Matsubara, S. J. Am. Chem. Soc.
2008, 130, 17226. (b) Jobashi, T.; Hino, T.; Maeyama, K.; Ozaki, H.; Ogino,
ꢀ
K.; Yonezawa, N. Chem. Lett. 2005, 34, 860. (c) Goossen, L. J.; Rodrrguez,
N. Chem. Commun. 2004, 724. (d) Goossen, L. J.; Paetzold, J. Adv. Synth.
Catal. 2004, 346, 1665. (e) Myers, A. G.; Tanaka, D.; Mannion, M. R. J. Am.
Chem. Soc. 2002, 124, 11250. (f) Goossen, L. J.; Paetzold, J.; Winkel, L.
Synlett 2002, 1721. (g) Chatani, N.; Tatamidani, H.; Ie, Y.; Kakiuchi, F.;
Murai, S. J. Am. Chem. Soc. 2001, 123, 4849.
(17) Jin, W. W.; Yu, Z. K.; He, W.; Ye, W. J.; Xiao, W.-J. Org. Lett.
2009, 11, 1317.

Note
Organometallics, Vol. 29, No. 4, 2010 1051
The target double-alkenylation products 5a and 5b were
obtained in 46-83% yields with minor formation of
the monoalkenylation products 6a (<5%) and 6b (<19%).
From the reaction of
reaction promoted by [RhCl(CO)2]2 afforded 5k in 63%
yield (entry 9).
arene 4c, only the monoalkenylation product 6c was
isolated (48%). However, under similar conditions the
reaction of 4a with cinnamic anhydride (7a) afforded
5a in 91% isolated yield.17 Thus, double-alkenylation of
4a with substituted cinnamic anhydrides was investiga-
ted in order to synthesize the desired products of type 5
(eq 4, Table 3).
With 5 mol % [RhCl(CO)2]2 as the catalyst, the reaction of
4a and 7a produced 5a in 88% yield (entry 1, Table 3),
exhibiting a lower efficiency than the catalytic system using
[RhCl(COD)]2 as the catalyst.17 Similar results were ob-
tained with 7b as the substrate (entry 2). In the case using
anhydride 7c and catalyst [RhCl(COD)]2, a 7:3 mixture of 5e
and 6e was collected (total yield 74%), whereas 5e was
isolated in 67% yield with [RhCl(CO)2]2 as the catalyst
(entry 3). From the reactions of 4a with anhydrides 7d-h,
[RhCl(COD)]2 exhibited a better catalytic efficiency than
[RhCl(CO)2]2, affording the desired double-alkenylation
products 5f-j in 63-95% yields (entries 4-8). However,
[RhCl(COD)]2-catalyzed reaction of 4a with 7i formed a 6:5
mixture of 5k and 6k in 63% total yield, while the same
Intrigued by an interest in poly(C-H functionalization) of
arenes by means of our recently developed methodologies,7c,17
the one-pot reactions of benzo[h]quinoline (1) with iso-
phthaloyl dichloride (2o), terephthaloyl dichloride (2p),
and benzene-1,3,5-tricarbonyl chloride (2r) were carried
out to produce the polyarene products, respectively (eqs 5
and 6). Using 10 mol % [RhCl(COD)]2 as the catalyst,
treatment of 1 with 3.0 equiv of 2o or 2p in refluxing
o-xylene afforded the target diarylation products 8 (44%)
and 9 (32%), respectively (eq 5). However, the ortho-diacid
dichloride, i.e., phthaloyl dichloride (2q), did not undergo
the same type of decarbonylative arylation with 1, pre-
sumably due to the higher steric hindrance from the
ortho-substituents. Interestingly, the acid trichloride (2r)
underwent poly(decarbonylation) to form the triarylation
product, i.e., 10, in 38% yield (eq 6). As π-conjugated
systems, aromatic compounds 8-10 may be potentially
applied in the manufacture of electronic devices.2a
Table 3. Direct Alkenylation of 2-Phenylpyridine (4a) via De-
carbonylation of Substituted Cinnamic Anhydrides (7) and C-H
Bond Activationa
A plausible mechanism is proposed in Scheme 1 by demon-
strating the reaction of 1 with acid chloride or anhydride (2).
Initially, the acid chloride or anhydride is oxidatively added to
the Rh(I) center, forming an aroyl- or acryloyl-chlorometal
complex RCORh(III)Cl(X) (11), which undergoes decarbo-
nylation to generate aryl- or alkenyl-chlororhodium(III) spe-
cies (12) at elevated temperatures. Species 12 reacts with arene
1 to produce intermediate complex 13 by C-H bond activa-
tion via intramolecular ortho-chelating assistance in the pre-
sence of a base. The target product 3 is then formed via the
reductive elimination of 13. Such a proton abstraction me-
chanism is reasonable to explain the C-H functionalization
of arenes by acid chlorides and anhydrides.18 It is also possible
for the reaction to occur via a decarbonylative concerted
metalation deprotonation (CMD) mechanism.19
entry
1
R
catalyst
product
yieldb (%)
Ph (7a)
[Rh(COD)Cl]2
[Rh(CO)2Cl]2
[Rh(COD)Cl]2
[Rh(CO)2Cl]2
[Rh(COD)Cl]2
[Rh(CO)2Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(CO)2Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(CO)2Cl]2
5a
5a
5d
5d
91c
88
2
2-MeC6H4 (7b)
4-MeC6H4 (7c)
96
79
3d
5eþ6e
74 (7:3)e
5e
67
95
63
In conclusion, efficient regioselective direct alkenylation
of arene C-H bonds has been achieved by means of Rh(I)-
catalysis using substituted cinnamoyl chlorides and cinnamic
anhydrides as the coupling partners via decarbonylative
C-H bond activation with arene or N-heteroaromatic
4
5
3-OMeC6H4 (7d)
4-OMeC6H4 (7e)
5f
5g
5gþ6g
72 (5:1)e
83
92
6
4-ClC6H4 (7f)
3-CF3C6H4 (7g)
2-naphthyl (7h)
2-furyl (7i)
5h
5i
7
8f
9
5j
67
63 (6:5)e
63
5kþ6k
(18) (a) Ozdemir, I.; Demir, S.; Cetinkaya, B.; Gourlaouen, C.;
Maseras, F.; Bruneau, C.; Dixneuf, P. H. J. Am. Chem. Soc. 2008,
130, 1156. (b) Lafrance, M.; Rowley, C. N.; Woo, T. K.; Fagnou, K. J. Am.
Chem. Soc. 2006, 128, 8754.
5k
a Conditions: 4a, 0.5 mmol; 7, 1.5 mmol; catalyst, 5 mol %; Na2CO3,
4.0 equiv; 4 A molecular sieves; o-xylene, 3 mL; 145 °C, 12 h. b Isolated
yields. c Ref 17. d 24 h. e Molar ratio of 5 to 6 determined by 1H NMR
analysis. f 18 h.
´
(19) Garcıa-Cuadrado, D.; de Mendoza, P.; Braga, A. A. C.;
Maseras, F.; Echavarren, A. M. J. Am. Chem. Soc. 2007, 129, 6880.

1052 Organometallics, Vol. 29, No. 4, 2010
Ye et al.
Scheme 1. Proposed Mechanism
tube were successively added [Rh(CO)2Cl]2 (10 mg, 0.025 mmol),
Na2CO3 (212 mg, 2.0 mmol), 4 A molecular sieves (600 mg),
2-phenylpyridine 4a (78 mg, 0.5 mmol), cinnamic anhydride 7a
(439 mg, 1.5 mmol), and o-xylene (3 mL). The Schlenk tube was
equipped with an air condenser, and the mixture was stirred
at 145 °C for 12 h. After cooling to ambient temperature,
the resulting mixture was filtered through a short pad of
Celite and rinsed with 20 mL of toluene. All the volatiles were
evaporated from the combined filtrate under reduced pressure,
and the resultant residue was purified by flash silica gel
column chromatography (eluent: petroleum ether (60-90 °C)/
CH2Cl2, 20:1, v/v), affording the target product 5a as a white solid
(159 mg, 88%).
Typical Procedure for Poly(arylation) with Benzo[h]quinoline
(1): Reaction of 1 with Isophthaloyl Dichloride (2o). Under a
nitrogen atmosphere, to a 25 mL Schlenk tube were successively
added [Rh(COD)Cl]2 (25 mg, 0.05 mmol), Na2CO3 (213 mg,
2.0 mmol), 4 A molecular sieves (1000 mg), benzo[h]quinoline 1
(224 mg, 1.25 mmol), isophthaloyl dichloride 2o (100 mg,
0.5 mmol), and o-xylene (5 mL). The Schlenk tube was equipped
with an air condenser, and the mixture was stirred at 145 °C for
36 h. After cooling to ambient temperature, the resultant
mixture was filtered through a short pad of Celite and rinsed
with 20 mL of toluene. All the volatiles were evaporated from
the combined filtrate under reduced pressure, and the resulting
residue was purified by flash silica gel column chromatography
(eluent: petroleum ether (60-90 °C)/EtOAc, 30:1, v/v), afford-
ing the target product 8 as a white solid (96 mg, 44%).
substrates under phosphine-free conditions. Polyarenes were
successfully synthesized from the one-pot poly(arylation) of
poly(aroyl) di- or trichlorides with benzo[h]quinoline.
Experimental Section
Typical Procedure for Alkenylation of Benzo[h]quinoline (1):
Alkenylation of 1 with Cinnamoyl Chloride (2a). Under a nitro-
gen atmosphere, to a 25 mL Schlenk tube were successively
added [Rh(CO)2Cl]2 (10 mg, 0.025 mmol), Na2CO3 (186 mg,
1.75 mmol), 4 A molecular sieves (600 mg), benzo[h]quinoline 1
(89 mg, 0.5 mmol), cinnamoyl chloride 2a (250 mg, 1.5 mmol),
and o-xylene (5 mL). The reactor was equipped with an air
condenser, and the mixture was stirred at 145 °C for 24 h. After
cooling to ambient temperature, the resulting mixture was
filtered through a short pad of Celite and rinsed with 20 mL
of toluene. All the volatiles were evaporated from combined
filtrate under reduced pressure, and the resultant residue was
purified by flash silica gel column chromatography (eluent:
petroleum ether (60-90 °C)/CH2Cl2, 20:1, v/v), affording the
target product 3a as a colorless oil (108 mg, 77%).
Acknowledgment. We are grateful to the National
Basic Research Program of China (2009CB825300), the
National Natural Science Foundation of China
(20972157), and the Knowledge Innovation Program of
the Chinese Academy of Sciences (DICP K2009D04) for
support of this research.
Typical Procedure for Dialkenylation of 2-Arylpyridines (4):
Dialkenylation of 2-Phenylpyridine (4a) with Cinnamic Anhy-
dride (7a). Under a nitrogen atmosphere, to a 25 mL Schlenk
Supporting Information Available: Experimental procedures
and spectroscopic data for the new compounds. This material is
available free of charge via the Internet at http://pubs.acs.org.