PdCl2-promoted reactions of diaryl-substituted methylenecyclopropanes

Article abstract of DOI:10.1039/c0dt00059k

The PdCl₂-promoted reactions of methylenecyclopropanes (MCPs) 1 bearing diaryl substituents on the terminal double bond were carefully investigated. The solvents employed significantly affected the reaction outcomes. It was found that dimeric a

Full text of DOI:10.1039/c0dt00059k

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PAPER
www.rsc.org/dalton | Dalton Transactions
PdCl2-promoted reactions of diaryl-substituted methylenecyclopropanes†
Ming-Hui Qi,a Li-Xiong Shao*b and Min Shi*a,c
Received 3rd March 2010, Accepted 18th June 2010
DOI: 10.1039/c0dt00059k
The PdCl2-promoted reactions of methylenecyclopropanes (MCPs) 1 bearing diaryl substituents on the
terminal double bond were carefully investigated. The solvents employed significantly affected the
reaction outcomes. It was found that dimeric allylpalladium(II) complexes 2a–2f can be obtained as the
sole products in acceptable to good yields under mild reaction conditions with THF as the solvent,
while dimeric allylpalladium(II) complexes 2a–2f along with another type of dimeric allylpalladium(II)
complexes 4a–4e can be obtained in good to high total yields if N,N-dimethylacetamide (DMAc) was
used as the solvent. Moreover, using N,N-dimethylformamide (DMF) as the solvent in the presence of
water, it was found that water can also participate in the reaction to form another type of dimeric
allylpalladium(II) complex 6 as the minor product. All of these dimeric allylpalladium(II) complexes
reported in the paper have been characterized by X-ray crystal structure diffraction.
Table 1 Optimization for the reaction of MCP 1a with Pd source
Introduction
Methylenecyclopropanes (MCPs) 1 are highly strained but readily
accessible molecules that have served as useful building blocks
in organic synthesis.1 The transition metal-mediated chemistry of
MCPs 1 has been widely explored during the past few decades
and the developments in this field have been comprehensively
Entrya
Ln
Temp.
rt
Time/h
Yield/%b
reviewed by Binger,2 Donaldson,3 Lautens,4 Yamamoto,5 Rubin
and Gevorgyan.6 Besides transition metals, Lewis acids such
as Ln(OTf)3 (Ln = Yb, Sc, La, etc.) mediated reactions of
MCPs 1 have are also been extensively investigated in the past
decade and it was found that the corresponding products can
be obtained via the selective cleavage of the proximal bond.7
In the early 1980s, Hughes and co-workers extensively inves-
tigated the PdCl2(PhCN)2-mediated chloropalladation reaction
of MCPs bearing substituent(s) on the cyclopropyl ring to give
the corresponding dimeric allylpalladium(II) complex at room
temperature,8 in contrast, MCP bearing two methyl groups on
the terminal double bond (isopropylidenecyclopropane) showed
no tendency to undergo the chloropalladation reaction and was
unchanged even after refluxing with PdCl2(PhCN)2 in benzene
for 8 h.8 In 2008, Huang and co-workers reported that in
the presence of PdCl2(NHC) (NHC = N-heterocyclic carbene)
catalyst, MCPs 1 can undergo the cycloisomerization reaction
to give the corresponding dihydronaphthalene derivatives.9 In
1
2
3
4
5
6
7
none
none
none
(CH3CN)2
(PhCN)2
(PPh3)2
dppe
24
24
24
24
24
24
24
58
74
74
57
52
N.R.
28
50 ◦
C
reflux
50 ◦
50 ◦
50 ◦
50 ◦
C
C
C
C
a All reactions were carried out using MCP 1a (0.3 mmol), Pd source
(0.33 mmol) and THF (1.0 mL) at the listed temperature.
b Isolated yields.
our laboratory, it was found that in the presence of PdCl2, the
chloropalladation reactions of MCPs 1 bearing two aryl groups
on the terminal double bond can afford dimeric allylpalladium(II)
complexes 2a–2f, 4a–4e, 5 and 6 in good to high yields under
different reaction conditions. Herein we wish to report these results
in detail.10
Results and discussion
aLab for Advanced Materials and Institute of Fine Chemicals, East China
University of Science and Technology, 130 Meilong Road, Shanghai, 200237,
P. R. China. E-mail: mshi@mail.sioc.ac.cn; Fax: 86-21-64146128; Tel: 86-
21-54925137
Formation of dimeric allylpalladium(II) complexes
Initial examinations were carried out using MCP 1a (R1 = R2 = Ph)
(0.3 mmol) and PdCl2 (0.33 mmol) as the substrates under various
conditions. Of the solvents and reaction temperatures screened, it
was found that when the reaction was carried out at 50 ◦C or under
reflux in THF, the best result can be obtained with the formation
of the dimeric allylpalladium(II) complex 2a in 74% yield in both
cases (Table 1, entries 2 and 3) and 2a was obtained in 58% yield
at room temperature (20 ◦C) (Table 1, entry 1) (please see ESI for
more details†). For all other PdCl2 complexes investigated instead
of PdCl2 for this reaction, inferior results were obtained under
the standard conditions. For instance, when PdCl2(CH3CN)2 and
bCollege of Chemistry and Materials Engineering, Wenzhou Univer-
sity, Chashan University Town, Wenzhou, 325035, Zhejiang Province,
P. R. China. E-mail: shaolix@wzu.edu.cn; Fax: 86-577-88373111; Tel: 86-
577-88373111
cState Key Laboratory of Organometallic Chemistry, Shanghai Institute
of Organic Chemistry, Chinese Academy of Sciences, 354 Lingling Road,
Shanghai, 200032, China
† Electronic supplementary information (ESI) available: Experimental
procedures, spectroscopic data and crystallographic information files for
complexes 2a, 3a, 4a, 3b, 6 and 7. CCDC reference numbers 620092,
621667, 646598, 744566, 744567, 758823. For ESI and crystallographic
data in CIF or other electronic format see DOI: 10.1039/c0dt00059k
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PdCl2(PhCN)2 were used in this reaction, complex 2a was formed
in 57 and 52% yields, respectively (Table 1, entries 4 and 5).
When PdCl2(dppe) [dppe = 1,2-bis(diphenylphosphino)ethane]
was employed in this reaction, only 28% yield of complex 2a
was formed (Table 1, entry 7), while PdCl2(PPh3)2 showed no
activity for this transformation (Table 1, entry 6). The structure of
complex 2a was unambiguously determined by X-ray diffraction.
The ORTEP drawing is shown in Fig. 1 and its CIF data are
presented in the ESI.†11 It should also be noted here that 2a may
exist in two isomers (trans-2a and cis-2a).12 On the basis of its 1H
NMR, 13C NMR and X-ray diffraction, it may be concluded here
that only the trans-isomer was obtained as the thermodynamically
favored isomer as previously reported by Hughes.8
has two methoxy groups on the phenyl rings, the reaction became
disordered at 50 ◦C and no detectable product was obtained. We
found that if the corresponding reaction was carried out at room
temperature (25 ◦C), the corresponding product 2d could also be
obtainedthough onlyin19% isolated yield (Table 2, entry 3). As for
the unsymmetrical diaryl-substituted MCP 1f, the reaction only
gave the corresponding product 2f in 26% yield as a Z,Z- and Z,E-
isomeric mixture, in which the ratio could not be determined by
1H NMR spectroscopic data (see ESI† for details) (Table 2, entry
5). It should also be noted here that for other MCPs as R1 = aryl,
R2 = alkyl or hydrogen and R1, R2 = alkyl, the reactions became
disordered and although some major products can be isolated
from these reactions in low to acceptable yields, their structures
remain undetermined at this stage.
When PdBr2 was used as the reagent to the reaction with
MCP 1a, the corresponding dimeric allylpalladium(II) complex
3a was obtained in 89% yield at 60 ◦C under standard conditions
(Scheme 1). The structure of 3a was also determined by X-ray
diffraction (Fig. 2) and its CIF data are presented in the ESI.†13
Scheme 1 Reaction of MCP 1a with PdBr2 in THF.
Fig. 1 ORTEP drawing of dimeric allylpalladium(II) complex 2a with
thermal ellipsoids at the 30% probability level. Selected bond distances (A)
˚
and angles (deg): C1–C2 = 1.420(5), C2–C3 = 1.416(6), Pd–C1 = 2.158(3),
Pd–C2 = 2.107(4), Pd–C3 = 2.088(4), Pd–Cl1 = 2.3832(10), Pd–Cl1A
2.4178(11), C3–Pd–C2 = 39.44(15), C2–Pd–C1 = 38.88(14), C3–Pd–C1
69.44(16), Cl1–Pd–Cl1A = 87.95(3), C3–Pd–Cl1 = 99.95(12), C1–Pd–Cl1A
102.09(11).
=
=
=
Under the optimized reaction conditions, a variety of MCPs 1
were investigated to examine the reaction generality and the results
are summarized in Table 2. As shown in Table 2, in the cases of the
symmetrical diaryl-substituted MCPs 1 such as 1b, 1c and 1e, the
corresponding dimeric allylpalladium(II) complexes 2b, 2c and 2e
could be obtained in moderate yields within 24 h under identical
conditions (Table 2, entries 1, 2 and 4). As for MCP 1d, which
Table 2 Reactions of MCPs 1 with PdCl2 in THF
Fig. 2 ORTEP drawing of dimeric allylpalladium(II) complex 3a with
˚
thermal ellipsoids at the 30% probability level. Selected bond distances (A)
and angles (deg): C1–C2 = 1.429(19), C2–C3 = 1.44(2), Pd1–C1 = 2.089(15),
Pd1–C2 = 2.117(14), Pd1–C3 = 2.168(13), Pd1–Br1 = 2.5095(17), Pd1–Br2 =
2.535(2), C2–Pd1–C3 = 39.3(5), C1–Pd1–C2 = 39.7(5), C1–Pd1–C3 = 70.1(6),
Br1–Pd1–Br2 = 87.70(6), C1–Pd1–Br1 = 97.9(4), C3–Pd1–Br2 = 103.3(4).
Entrya
1 (R1/R2)
Yield/%b
When the above transformations were carried out at 50 ◦C using
N,N-dimethylacetamide (DMAc) as the solvent instead of THF,
complexes 2a–2f were obtained in comparable to higher yields
along with another type of complexes 4a–4f in low yields in most
cases (Table 3), which clearly showed that solvent could participate
in this chloropalladation reaction as previously mentioned by
Hughes.8 It seems that the reaction temperature slightly affects the
ratio between products 2a–2f and 4a–4e. For example, when the
reaction of 1a with PdCl2 was carried out at room temperature,
1
1b (4-MeC6H4/4-MeC6H4)
1c (4-FC6H4/4-FC6H4)
1d (4-MeOC6H4/4-MeOC6H4)
1e (4-ClC6H4/4-ClC6H4)
1f (4-ClC6H4/C6H5)
2b, 62
2c, 68
2d, 19
2e, 59
2f, 26d
2
3c
4
5
a Otherwise specified, all reactions were carried out using 1 (0.3 mmol),
PdCl2 (0.33 mmol) and THF (1.0 mL) at 50 ◦C for 24 h. b Isolated yields.
c The reaction was carried out at room temperature for 24 h. d Mixture of
Z,Z- and Z,E-isomers.
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Table 3 Reaction of MCPs 1 with PdCl2 in DMAc
When 3.0 equiv of NaBr was in◦troduced into the reaction of
MCP 1e with PdCl2 in THF at 50 C, interestingly, it was found
that complex 3b was formed in 93% yield as the sole product
(Scheme 2). The structure of complex 3b was unambiguously
determined by X-ray diffraction (Fig. 4) and its CIF data are
presented in the ESI.†15
Yield/%b
2
Entrya 1 (R1/R2)
Time/h
4
1c
2
3
4
5
6
7
1a (C6H5/C6H5)
30
30
24
24
2a, 65
2a, 88
2b, 57
2c, 77
2d, 38
2e, 45
2f, 80d
4a, 21
4a, 9
4b, 5
4c, 14
—
1a
1b (4-MeC6H4/4-MeC6H4)
1c (4-FC6H4/4-FC6H4)
1d (4-MeOC6H4/4-MeOC6H4) 24
1e (4-ClC6H4/4-ClC6H4)
1f (4-ClC6H4/C6H5)
24
24
4d, 28
4e, 13d
a Unless otherwise specified, all reactions were carried out using 1
(0.3 mmol), PdCl2 (0.33 mmol), DMAc (1.0 mL) at 50 ◦C for the listed
time. b Isolated yields. c The reaction was carried out at room temperature.
d Mixture of Z,Z- and Z,E-isomers.
Scheme 2 Reaction of MCP 1e with PdCl2 in the presence of NaBr in
THF at 50 ◦C.
product 2a was obtained in 65% yield along with 21% yield of
product 4a (Table 3, entry 1). For example, when the reaction
was carried out at 50 ◦C, the yield of 2a was increased to 88%
while the yield of 4a was decreased to 9% (Table 3, entry 2). In
the case of MCP 1d, the corresponding dimeric allylpalladium(II)
complex 2d was obtained as the sole product in relatively higher
yield (Table 2, entry 3 vs. Table 3, entry 5). For the reaction of
unsymmetrical MCP 1f with PdCl2, the yield of product 2f was
increased dramatically to 80% along with the formation of product
4e in 13% yield in DMAc (Table 2, entry 5 vs. Table 3, entry 7). The
structure of complex 4a was unambiguously determined by X-ray
diffraction (Fig. 3) and its CIF data are presented in the ESI.†14
Fig. 4 ORTEP drawing of dimeric allylpalladium(II) complex 3b with
thermal ellipsoids at the 30% probability level. Selected bond distances (A)
and angles (deg): C1–C2 = 1.462(14), C2–C4 = 1.466(12), Pd1–C1 = 2.090(9),
Pd1–C2 = 2.175(10), Pd1–C4 = 2.186(10), Pd1–Br1 = 2.5468(12), Pd1–Br2 =
˚
2.5010(14), C2–Pd1–C4 = 39.3(3), C1–Pd1–C2 = 40.0(4), C1–Pd1–C4
70.6(4), Br2–Pd1–Br1 = 89.67(4), C2–Pd1–Br1 = 140.4(3), C1–Pd1–Br2
94.6(3).
=
=
Furthermore, we also found that water can significantly affect
the reaction outcome (Table 4). For example, as for the reaction of
MCP 1a with PdCl2 in N,N-dimethylformamide (DMF) at room
temperature, when 0, 1.1 or 2.0 equiv of H2O was added, complexes
2a and 5 were formed in moderate total yields (Table 4, entries 1–
3). While when the employed amount of H2O was increased to 5 or
10 equiv, except that complex 2 was obtained as the major product,
complex 6 was obtained in 17 and 8% yields as the minor product
without the formation of complex 5 in both cases (Table 4, entries
4 and 5). The structure of complex 6 was also unambiguously
determined by X-ray diffraction (Fig. 5) and its CIF data are
presented in the ESI.†16
It was reported by Nolan and co-workers in 2006 that
transforming simple [Pd(R–allyl)Cl]2 into (NHC)Pd(R–allyl)Cl
complexes [NHC: N,N¢-bis(2,6-diisopropylphenyl)imidazol-2-
ylidene or N,N¢-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazol-
2-ylidene; R = H, Me, gem-Me2, Ph] can significantly improve the
catalytic activity of the corresponding Pd complexes in Suzuki–
Miyaura and Buchwald–Hartwig reactions.17 In this laboratory,
we also carried out a similar transformation with 2a and IPr·HCl
Fig. 3 ORTEP drawing of dimeric allylpalladium(II) complex 4a with
thermal ellipsoids at the 30% probability level. Selected bond distances (A)
and angles (deg): C1–C2 = 1.429(5), C2–C3 = 1.393(5), Pd–C1 = 2.165(3),
˚
Pd–C2 = 2.112(4), Pd–C3 = 2.089(4), Pd–Cl1 = 2.4184(11), Pd–Cl1A
2.4117(10), C3–Pd–C2 = 38.72(14), C2–Pd–C1 = 39.00(14), C3–Pd–C1
=
=
69.07(15), Cl1A–Pd–Cl1 = 88.16(4), C3–Pd–Cl1A = 98.53(12), C1–Pd–Cl1 =
104.11(11).
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Table 4 Reaction of MCP 1a with PdCl2 in DMF in the presence of H2O
Scheme 3 Synthesis of (NHC)–Pd complex 7 from 2a.
Yield/%b
Entrya
H2O (equiv)
2a
5
6
1
2
3
4
5
0
1.1
2
5
10
41
30
41
30
32
20
31
20
17
8
a All reactions were carried out using MCP 1a (0.3 mmol), PdCl2
(0.33 mmol), DMF (1.0 mL) and the listed amount of H2O at room
temperature for 24 h. b Isolated yields.
Fig. 6 ORTEP drawing of dimeric allylpalladium(II) complex 7 with
thermal ellipsoids at the 30% probability level. Selected bond distances
˚
(A) and angles (deg): C1–C2 = 1.410(7), C2–C4 = 1.407(7), Pd–C1
=
2.074(5), Pd–C2 = 2.107(5), Pd–C4 = 2.257(6), Pd–C5 = 2.028(5), Pd–Cl1 =
2.3560(15), C2–Pd–C4 = 37.43(19), C1–Pd–C2 = 39.4(2), C1–Pd–C4
68.5(2), C2–Pd–Cl1 = 130.83(17), C4–Pd–Cl1 = 99.71(15), C1–Pd–Cl1
168.08(17).
=
=
Fig. 5 ORTEP drawing of dimeric allylpalladium(II) complex 6 with
thermal ellipsoids at the 30% probability level. Selected bond distances (A)
˚
and angles (deg): C1–C2 = 1.421(8), C2–C3 = 1.401(8), Pd1–C1 = 2.139(6),
Pd1–C2 = 2.110(6), Pd1–C3 = 2.113(6), Pd1–Cl1 = 2.4080(16), Pd1–Cl2
2.4121(17), C2–Pd1–C3 = 38.8(2), C2–Pd1–C1 = 39.1(2), C3–Pd1–C1
69.1(2), Cl1–Pd1–Cl2 = 86.08(5), C3–Pd1–Cl1 = 98.68(18), C1–Pd1–Cl2
106.13(16).
=
=
=
Scheme 4 Plausible mechanism for the halopalladation of MCPs 1.
[IPr·HCl = 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride]
t
as the substrates and BuOK as the base. It was found that the
To further illustrate the formation of complexes 3b, 4 or 5 and
6 in detail, some control experiments were carried out. One is that
2a (0.1 mmol) was stirred in DMF (1.0 mL) at 50 ◦C for 24 h. The
result showed that besides the starting materials 2a was recovered
in 66% yield, complex 5 was obtained in 20% yield (Scheme 5).
This result suggested that 5 may be derived from the reaction of
product 2a with DMF, but the real mechanism for the formation
of product 5 is unclear at this stage.
corresponding (NHC)Pd(allyl)Cl complex 7 could be obtained
in 41% yield (Scheme 3). The structure of complex 7 was also
unambiguously determined by X-ray diffraction (Fig. 6) and its
CIF data are presented in the ESI.†18
Preliminary investigations on the reaction mechanism
Based on the previously reported results, the plausible mechanism
for this type of halopalladation reaction of MCPs 1 is shown
in Scheme 4.8 Firstly, coordination of PdX2 to MCPs 1 gives
intermediate 8. Secondly, migration of the halogen atom directly
from the Pd center gives the halopalladation products 2 (X = Cl)
or 3 (X = Br) with the distal bond cleavage in high selectivity
(Scheme 4).
The second is that a mixture of 2a (0.15 mmol) and H2O
(0.90 mmol) was stirred in THF (1.0 mL) or DMF (1.0 mL) at
room temperature (rt) to 50 ◦C for 12 h, respectively (Scheme 6).
The results showed that no reaction occurred in both cases. These
results suggested that complex 6 may not be derived from product
2a via hydrolysis. But the real mechanism for the formation of
complex 6 also remains unclear at this stage.
8832 | Dalton Trans., 2010, 39, 8829–8834
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Procedure for the reaction of MCP 1a with PdBr2 in THF
Under an argon atmosphere, a mixture of MCP 1a (0.30 mmol)
and PdBr2 (0.33 mmol) was stirred in anhydrous THF (1.0 mL) at
60 ◦C for 24 h. The solvent was removed under reduced pressure,
and the residue was purified by flash chromatography on silica gel
to give complex 3a.
Scheme 5 Transformation of 2a in DMF at 50 ◦C.
General procedure for the reaction of MCPs 1 with PdCl2 in
DMAc
Under an argon atmosphere, a mixture of MCPs 1 (0.30 mmol)
and PdCl2 (0.33 mmol) was stirred in anhydrous DMAc (1.0 mL)
at 50 ◦C for 24 h. The reaction solution was diluted with EtOAc,
washed with saturated brine, dried over anhydrous Na2SO4, and
then purified by flash column chromatography on silica gel to give
complexes 2 and 4.
Scheme 6 Reaction of 2a with H2O in THF or DMF.
Procedure for the reaction of MCP 1e with PdCl2 in THF in the
presence of NaBr
The third is that 2a (0.15 mmol) was treated with NaBr
(0.90 mmol) in THF (1.0 mL) at 50 ◦C for 12 h. Only another
complex 9, instead of complex 3b as expected, was obtained
as the sole product in 77% yield, which may be derived from
transhalogenation of 2a with NaBr (Scheme 7). The structure
A mixture of MCP 1e (0.30 mmol), PdCl2 (0.33 mmol) and◦NaBr
(0.9 mmol) was stirred in anhydrous THF (1.0 mL) at 50 C for
12 h. The solvent was removed under reduced pressure, and the
residue was purified by flash chromatography on silica gel to give
complex 3b.
1
of complex 9 was determined by H NMR, 13C NMR, MS and
HRMS (see the ESI for details†). This result suggested that
compound 3b might be obtained via the reaction of MCP 1e with
PdBr2 derived from PdCl2 and NaBr (Scheme 2 vs. Scheme 7).
Procedure for the reaction of MCP 1a with PdCl2 in DMF in the
presence of H2O
Under an argon atmosphere, a mixture of MCP 1a (0.30 mmol),
PdCl2 (0.33 mmol) and H2O (0.6 mmol to 3 mmol) was stirred
in anhydrous DMF (1.0 mL) at room temperature for 24 h. The
reaction solution was diluted with EtOAc, washed with saturated
brine, dried over anhydrous Na2SO4, and then purified by flash
column chromatography on silica gel to give complexes 2 and/or
5 and/or 6.
Scheme 7 Reaction of 2a with NaBr in THF at 50 ◦C.
Procedure for the formation of complex 7
Under an argon atmosphere, a mixture of complex 2a (0.05 mmol),
Conclusions
t
IPr·HCl (0.11 mmol) and BuOK (0.25 mmol) was stirred in
In conclusion, we have described the PdCl2 mediated reactions
of MCPs in THF for the formation of dimeric allylpalladium(II)
complexes in this paper. The dimeric allylpalladium(II) complexes
were isolated and were fully characterized by X-ray diffraction.
The examination of solvent effects revealed that in DMAc, DMF
and H2O, other novel dimeric allylpalladium(II) complexes could
be isolated though in low yields. Efforts are underway to further
illustrate the mechanistic details of the transition metal mediated
reactions of MCPs in this laboratory.
anhydrous THF (1.0 mL) at room temperature for 12 h. The
solvent was removed under reduced pressure, and the residue was
purified by flash column chromatography on silica gel to give
complex 7.
Acknowledgements
Financial support from the Shanghai Municipal Committee
of Science and Technology (06XD14005 and 08dj1400100-2),
National Basic Research Program of China (973-2009CB825300),
and the National Natural Science Foundation of China (20872162,
20672127, 20732008 and 20702013) and Mr. Jie Sun for perform-
ing the X-ray diffraction is gratefully acknowledged.
Experimental
General procedure for the reaction of MCPs 1 with PdCl2 in THF
Under an argon atmosphere, a mixture of MCPs 1 (0.30 mmol)
and PdCl2 (0.33 mmol) was stirred in anhydrous THF (1.0 mL) at
50 ◦C for 24 h. The solvent was removed under reduced pressure,
and the residue was purified by flash chromatography on silica gel
to give complex 2.
References
1 For the synthesis of MCPs:A. Brandi and A. Goti, Chem. Rev., 1998, 98,
589; Carbocyclic Three-Membered Ring Compounds, in Houben-Weyl,
Vol. E17a-c, (Ed.: A. de Meijere), Thieme, Stuttgart, 1996.
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3 W. A. Donaldson, Adv. Met. Org. Chem., 1991, 2, 269.
4 M. Lautens, Y. Ren, P. Delanghe, P. Chiu, S. Ma and J. Colucci,
Can. J. Chem., 1995, 73, 1251.
13 The crystal data of 3a have been deposited in CCDC with number
744567. Empirical Formula: C32H26Br4Pd2; Formula Weight: 942.97;
Crystal color, Habit: green, prismatic; Crystal dimensions: 0.256 ¥
0.103 ¥ 0.094 mm; Crystal system: Triclinic; Lattice parameters: a =
5 I. Nakamura and Y. Yamamoto, Adv. Synth. Catal., 2002, 344, 111.
6 M. Rubin, M. Rubina and V. Gevorgyan, Chem. Rev., 2007, 107, 3117.
7 For a review on the Lewis acid-mediated ring-opening reactions of
MCPs, please see: L.-X. Shao and M. Shi, Curr. Org. Chem., 2007,
11, 1135and references therein; for recent selected papers of the Lewis
acid-mediated cycloaddition reactions of MCPs from this group, please
see: M. Shi, L.-X. Shao and B. Xu, Org. Lett., 2003, 5, 579; L.-X. Shao
and M. Shi, Adv. Synth. Catal., 2003, 345, 963; M. Shi, B. Xu and J.-W.
Huang, Org. Lett., 2004, 6, 1175; L.-X. Shao, B. Xu, J.-W. Huang and
M. Shi, Chem.–Eur. J., 2006, 12, 510.
◦
˚
˚
˚
9.3228(16) A, b = 12.31◦1(2) A, c = 14.328(2) A, a = 88.057(4) , b =
◦
3
˚
77.018(3) , g = 82.383(3) , V = 1588.3(5) A ; T = 293(2) K; Space group:
P1vphantom1; Z = 2; Dc = 1.972 g cm-3; F000 = 900; Diffractometer:
Bruker SMART; Reflections collected/unique: 8721/6108 (Rint
0.0322); Final R indices [I > 2s(I)]: R1 = 0.0786, wR2 = 0.2723.
¯
=
14 The crystal data of 4a have been deposited in CCDC with number
744566. Empirical Formula: C36H36Cl2N2O2Pd2; Formula Weight:
812.37; Crystal color, Habit: yellow, prismatic; Crystal dimensions:
0.176 ¥ 0.105 ¥ 0.051 mm; Crystal system: Monoclinic; Lattice param-
◦
˚
˚
˚
˚
8 B. K. Dallas and R. P. Hughes, J. Organomet. Chem., 1980, 184, C67;
P. R. Clemens, R. P. Gughes and L. D. Margerum, J. Am. Chem. Soc.,
1981, 103, 2428; T. A. Albright, P. R. Clemens, R. P. Hughes, D. E.
Hunton and L. D. Margerum, J. Am. Chem. Soc., 1982, 104, 5369;
B. K. Dallas, R. P. Hughes and K. Schumann, J. Am. Chem. Soc.,
1982, 104, 5380; R. P. Hughes and C. S. Day, Organometallics, 1982, 1,
1221; M. Green and R. P. Hughes, J. Chem. Soc., Dalton Trans., 1976,
1880; M. Green and R. P. Hughes, J. Chem. Soc., Dalton Trans., 1976,
1890; R. P. Hughes, D. E. Hunton and K. Schumann, J. Organomet.
Chem., 1979, 169, C37; R. Noyori and H. Takaya, J. Chem. Soc., Chem.
Commun., 1969, 525.
eters: a = 13.8◦340(11) A, b = 10.3767(8) A, c = 12.6185(10) A, a = 90 , b =
◦
3
112.7140(10) , g = 90 , V = 1670.9(2) A ; T = 293(2) K; Space group:
P21/c; Z = 2; Dc = 1.615 g cm-3; F000 = 816; Diffractometer: Bruker
SMART; Reflections collected/unique: 9528/3615 (Rint = 0.0706); Final
R indices [I > 2s(I)]: R1 = 0.0390, wR2 = 0.0711.
15 The crystal data of 3b have been deposited in CCDC with num-
ber 758823. Empirical Formula: C32H24Br4Cl4Pd2; Formula Weight:
1082.75; Crystal color, Habit: green, prismatic; Crystal dimensions:
0.265 ¥ 0.113 ¥ 0.101 mm; Crystal system: Monoclinic; Lattice
˚
˚
˚
=
=
Parameters: a = 10.7816(6) A, b = 27.7470(16) A, c = 25.1259(15) A,
= 90◦, b = 98.5670(10)◦, g = 90◦, V = 7432.7(7) A ; T
3
˚
a
293(2) K; Space group: P21/n; Z = 8; Dc = 2.011 g cm-3; F000
9 Y.-W. Yang and X. Huang, Synlett, 2008, 1825.
10 For transition metal catalyzed reactions of MCPs from this group,
please see: M. Shi, Y. Chen and B. Xu, Org. Lett., 2003, 5, 1225; M.
Shi, B.-Y. Wang and J.-W. Huang, J. Org. Chem., 2005, 70, 5606; M.
Shi, L.-P. Liu and J. Tang, J. Am. Chem. Soc., 2006, 128, 7430; M.
Shi and B.-Y. Wang, Synlett, 2006, 3158; M. Shi, B.-Y. Wang and
L.-X. Shao, Synlett, 2007, 909; G.-Q. Tian, Z.-L. Yuan, Z.-B. Zhu and
M. Shi, Chem. Commun., 2008, 2668; M. Shi, G.-Q. Tian and J. Li,
Tetrahedron, 2009, 65, 3404; M. Jiang and M. Shi, Organometallics,
2009, 28, 5600for preliminary results with vinylidenecyclopropanes as
the substrates from this group, please see: X.-X. Gu, F.-J. Wang, M.-H.
Qi, L.-X. Shao and M. Shi, Organometallics, 2009, 28, 1569–1574.
11 The crystal data of 2a have been deposited in CCDC with number
620092. Empirical Formula: C32H28Cl4Pd2; Formula Weight: 767.14;
Crystal color, Habit: yellow, prismatic; Crystal dimensions: 0.193 ¥
0.122 ¥ 0.099 mm; Crystal system: Monoclinic; Lattice parameters:
4296; Diffractometer: Bruker SMART; Reflections collected/unique:
40804/14600 (Rint = 0.0648); Final R indices [I > 2s(I)]: R1 = 0.0524,
wR2 = 0.1493.
16 The crystal data of 6 have been deposited in CCDC with number
621667. Empirical Formula: C32.67H30.67Cl4O2Pd2; Formula Weight:
809.84; Crystal color, Habit: yellow, prismatic; Crystal dimensions:
0.507 ¥ 0.281 ¥ 0.224 mm; Crystal system: Monoclinic; Lattice
˚
˚
˚
˚
pa◦rameters: a = 14.9609(9) A, b = 20.8396(13) A, c = 15.0025(9) A, a =
◦
◦
3
90 , b = 92.0760(10) , g = 90 , V = 4674.4(5) A ; T = 293(2) K; Space
group: P21/c; Z = 6; Dc = 1.677 g cm-3; F000 = 2352; Diffractometer:
Bruker SMART; Reflections collected/unique: 25386/9165 (Rint
0.0519); Final R indices [I > 2s(I)]: R1 = 0.0504, wR2 = 0.1373.
=
17 N. Marion, O. Navarro, J.-G. Mei, E. D. Stevens, N. M. Scott and S. P.
Nolan, J. Am. Chem. Soc., 2006, 128, 4101.
18 The crystal data of 7 have been deposited in CCDC with number
646598. Empirical Formula: C43H50Cl2N2Pd; Formula Weight: 772.15;
Crystal color, Habit: yellow, prismatic; Crystal dimensions: 0.501 ¥
0.234 ¥ 0.196 mm; Crystal system: Tetragonal; Lattice parameter◦s:
◦
˚
˚
˚
a = 9.182◦6(8) A, ◦b = 15.1250(13) A, c = 11.1711(10) A, a = 90 , b =
3
˚
97.164(2) , g = 90 , V = 1539.4(2) A ; T = 293(2) K; Space group: P21/n;
Z = 2; Dc = 1.655 g cm-3; F000 = 760; Diffractometer: Bruker SMART;
Reflections collected/unique: 8947/3355 (Rint = 0.0605); Final R indices
[I > 2s(I)]: R1 = 0.0404, wR2 = 0.0781.
˚
˚
˚
˚
a = 26.1371(13) ◦A, b = 26.1371(13) A, c = 23.7475(16) A, a = 90 ,
◦
3
b = 90 , g = 90 , V = 16223.1(16) A ; T = 293(2) K; Space group:
I4(1)/a; Z = 16; Dc = 1.265 g cm-3; F000 = 6432; Diffractometer: Bruker
SMART; Reflections collected/unique: 45818/8412 (Rint = 0.1242);
Final R indices [I > 2s(I)]: R1 = 0.0607, wR2 = 0.1348.
12 J.-M. Rosset, M. P. Glenn, J. D. Cotton, A. C. Willis, C. H. L. Kennard,
K. A. Byriel, B. H. Riches and W. Kitching, Organometallics, 1998, 17,
1968.
8834 | Dalton Trans., 2010, 39, 8829–8834
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The Royal Society of Chemistry 2010
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