The first definitive example of oxidative addition of acyclic vinyl selenide to M(0) complex

Article abstract of DOI:10.1016/j.jorganchem.2005.12.058

The principle of C-S bond activation of acyclic vinlyl sulfide by platinum(0)-complex was applied to the C-Se bond fission of vinyl selenide. The substrate possessing Ph and ArSe (Ar = C₆H₄Cl-p) substituents at the β-carbon successfully reacted with Pt(0)-complex at 25 °C to produce the vinyl platinum in good yield and its structure was unambiguously determined by X-ray crystallographic analysis. When (Z)-(Me ₃Si)(ArSe)C(H)(SeAr) was employed as a reaction substrate, following β-Se elimination took place to liberate Me₃SiCCH with the production of [trans-Pt(SeAr)₂(PPh₃)₂]. The oxidative addition of C-Se bond of (E)-(Ph)(H)CC(H)(SeAr) to Pt(0) was also confirmed at 25 °C, while no C-S bond-breaking occurred when the corresponding vinyl sulfide was exposed to the same reaction conditions, demonstrating that the cleavage of C-Se bond was more facile than that of C-S bond.

Full text of DOI:10.1016/j.jorganchem.2005.12.058

Journal of Organometallic Chemistry 691 (2006) 1873–1878
www.elsevier.com/locate/jorganchem
The first definitive example of oxidative addition of acyclic vinyl
selenide to M(0) complex
*
*
Hitoshi Kuniyasu , Tomohiro Kato, Masafumi Inoue, Jun Terao, Nobuaki Kambe
Department of Molecular Chemistry and Frontier Research Center, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
Received 2 November 2005; received in revised form 21 December 2005; accepted 27 December 2005
Available online 24 February 2006
Abstract
The principle of C–S bond activation of acyclic vinlyl sulfide by platinum(0)-complex was applied to the C–Se bond fission of vinyl
selenide. The substrate possessing Ph and ArSe (Ar = C6H4Cl-p) substituents at the b-carbon successfully reacted with Pt(0)-complex at
25 ꢀC to produce the vinyl platinum in good yield and its structure was unambiguously determined by X-ray crystallographic analysis.
When (Z)-(Me3Si)(ArSe)C@(H)(SeAr) was employed as a reaction substrate, following b-Se elimination took place to liberate
Me3SiCCH with the production of [trans-Pt(SeAr)2(PPh3)2]. The oxidative addition of C–Se bond of (E)-(Ph)(H)C@C(H)(SeAr) to
Pt(0) was also confirmed at 25 ꢀC, while no C–S bond-breaking occurred when the corresponding vinyl sulfide was exposed to the same
reaction conditions, demonstrating that the cleavage of C–Se bond was more facile than that of C–S bond.
ꢁ 2006 Elsevier B.V. All rights reserved.
Keywords: Oxidative addition; Vinyl selenide; Platinum; b-Se elimination
1. Introduction
dative addition of C–Se bond of selenoester to zero-valent
platinum complex [5]. On the other hand, regarding to the
oxidative addition of acyclic vinyl sulfide, we have recently
revealed the concept for the successful C–S bond activation
by Pt(0)-complex by introducing two substituents having a-
anion stabilization effect such as Ar, ArS, Me3Si and
MeOCH2 groups at b-carbon (Eq. (1)) [6]. Herein, the
application of the principle to the cleavage of C–Se bond
of vinyl selenide will be reported.
The oxidative addition of C–X bond (X; element or
functional group) to low-valent transition-metal-complex
(M) to form C–M–X fragment has been exploited as one
of the most fundamental reactions in organometallic chem-
istry [1]. With respect to the C–Se bond fission, however,
only sparse information has been provided for both stoichi-
ometric and catalytic reactions. Some stoichiometric C–Se
bond dissections of selenophenes by transition-metal-
complexes [2] and the oxidative addition of C–Se bond of
PhSePh to [Pt(PEt3)3] have been reported [3]. As to the cat-
alytic reactions, cross-coupling reactions between vinyl sel-
enides and Grignard reagents, in which oxidative additions
of C–Se bond to low-valent transition-metal-complexes
were supposedly participated, have also been documented
[4]. Independently, we have disclosed that the Pt-catalyzed
arylselenation of terminal alkyne was triggered by the oxi-
ð1Þ
2. Results and discussion
First, the reaction of (Z)-(Ph)(ArSe)C@C(H)(SeAr)
(Ar = C6H4Cl-p, 1a, 0.50 mmol) [7] with Pt(PPh3)2(C2H4)
(2, 0.50 mmol) in C6H6 (20 mL) was carried out to afford
*
Corresponding authors.
E-mail address: kuni@chem.eng.osaka-u.ac.jp (H. Kuniyasu).
0022-328X/$ - see front matter ꢁ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.12.058

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H. Kuniyasu et al. / Journal of Organometallic Chemistry 691 (2006) 1873–1878
{cis-Pt[(Z)-C(H)@C(SeAr)(Ph)](SeAr)(PPh3)2} (cis-3a) pat-
terned after the oxidative addition of vinyl sulfide with a
similar framework [6]. After the solution was stirred at
25 ꢀC for 30 min, cis-3a was obtained as an yellow solid
in 92% yield by simply adding hexane into the solution
(Eq. (2)).
ð2Þ
The 31P NMR spectrum of cis-3a showed a set of dou-
blets centered at d 17.4 (JP–P = 16 Hz, JPt–P = 1856 Hz)
and d 17.8 (JP–P = 16 Hz, JPt–P = 3280 Hz). The former
was assigned as PPh3 of trans to the vinyl carbon and
the latter as PPh3 of trans to the SeAr judging from the
JPt–P values. The cis-3a gradually isomerized to trans-3a
in solution at 25 ꢀC (cis/trans = 76/24 after 22 h). A good
crystal suitable for X-ray crystallographic analysis of cis-
3a was obtained by recrystallization from benzene/hexane
and its ORTEP diagram was shown in Fig. 1. Similarly to
the case of the oxidative addition of the corresponding 1-
phenyl-1,2-bis(arylthio)alkene to 2, it was confirmed that
the terminal C–Se bond was cleaved by the platinum com-
plex, providing the first definitive example of oxidative
addition of acyclic vinyl selenide to transition-metal com-
plex. On the other hand, the attempted isolation of {cis-
Pt[(Z)-C(H)@C(SeAr)(SiMe3)]-(SeAr)(PPh3)2} (cis-3b) by
the reaction of (Z)-(Me3Si)(ArSe)C@C(H)(SeAr) (Ar =
C6H4Cl-p, 1b) with 2 has failed due to the contamination
by impurity. Thus, the reaction of 1b (0.028 mmol) with 2
(0.020 mmol) in C6D6 (0.5 mL) at 25 ꢀC was next moni-
tored by 31P and 1H NMR spectra using S@P(C6H4-
OMe-p)3 as an internal standard (Eq. (3)).
Fig. 1. ORTEP diagram of cis-3a.
The 31P NMR chart taken after 20 min showed the forma-
tion of anticipated cis-3b by a set of doublets centered at d
14.4 (JP–P = 17 Hz, JPt–P = 1781 Hz) and d 18.7 (JP–P
17 Hz, JPt–P = 3395 Hz) in 55% yield. However, the spec-
trum also showed the generation of [trans-Pt(SeAr)2-
=
(PPh3)2] (trans-4) at
d 20.2 (JPt–P = 2766 Hz) and
[Pt(PPh3)2(Me3SiCCH)] (5) at d 29.0 (JP–P = 47 Hz, JPt–P
= 3758 Hz) and d 32.5 (JP–P = 47 Hz, JPt–P = 3672 Hz) in
21% and 11% yields, respectively. After 1 h, the production
of cis-3b (50%), trans-4 (39%) and 5 (9%) were confirmed.
Then the yields of cis-3b and 5 were gradually decreased,
while that of trans-4 was increased. After 21 h, the signals
of cis-3b and 5 were disappeared, and 92% of trans-4 was
confirmed by 31P NMR spectrum, while its 1H NMR spec-
trum showed the liberation of Me3SiCCH (6) in 83% yield.
ð3Þ

H. Kuniyasu et al. / Journal of Organometallic Chemistry 691 (2006) 1873–1878
1875
Scheme 1. Proposed reaction pathway of reaction of 1b with 2.
The foregoing results clearly showed that after the oxidative
addition of terminal C–Se bond of 1b to 2 took place, b-
SeAr elimination, a reverse process of insertion of 6 into
Se–Pt bond, took place to afford trans-4 and 6, the latter
of which was partially trapped by the Pt(0)-complex to fur-
nish 5 at the beginning stage of the reaction (Scheme 1) [8].
The facts that the complex 5 was eventually all consumed
and 6 was liberated in good yield indicated that 5 also re-
acted with 1b to yield cis-3b and 6.
To compare the reactivity of vinyl selenide with that of
vinyl sulfide, the reactions of (E)-(Ph)(H)C@C(H)(YAr)
(YAr = SC6H4Cl-p, 7; YAr = SeC6H4Cl-p, 1c) with 2 were
conducted. In the case of reaction using 7, the formation of
p-complex 8 [9] was confirmed in 78% yield with the
unreacted 2 (22%) at 25 ꢀC after 20 min; however, the signal
of {trans-Pt[(E)-C(H)@C(H)(Ph)](SAr)(PPh3)2} (9) [10] was
detected only in 3% yield even after 5 h at 60 ꢀC (Eq. (4)). In
stark contrast, the 31P NMR spectrum of the reaction of 1c
with 2 taken after 20 h at 25 ꢀC suggested the formation
of 6% of p-complex {Pt[(E)-(Ph)(H)C@C(H)(SeAr)]-
(PPh3)2} (10c) and 76% (cis/trans = 82/18) of {Pt[(E)-
C(H)@C(H)(Ph)](SeAr)(PPh3)2} (3c) (Eq. (5)), proving
higher reactivity of the vinyl selenide than the vinyl
sulfide toward the oxidative addition reaction [4]. After
50 h, all 10c was disappeared and 68% of 3c (cis/
trans = 53/47) was confirmed together with the unas-
signed by-products, indicating that the equilibrium
between 10c and cis-3c strongly leaned to the latter side.
Further heating the solution resulted in the complete
isomerization to thermodynamically more stable trans-3c
(41%).
ð5Þ
On the other hand, 31P NMR spectrum taken after 20 min
at 25 ꢀC of the reaction of H2C@C(H)(SeAr) (Ar =
C6H4Cl-p, 1d) with 2 resulted in quantitative formation
of p-complex {Pt[H2C@C(H)(SeAr)](PPh3)2} (10d), which
was stable for 25 h (Eq. (6)). Even when the solution was
heated at 60 ꢀC for 5 h, the suspected signal of either
trans-3d or 11 was detected only in 10% yield.
ð6Þ
In conclusion, the first definitive evidence of oxidative
addition of vinyl selenides to low-valent transition-metal-
complex to furnish vinyl platinum was demonstrated.
Foregoing experimental data were rationalized by assum-
ing that the oxidative addition of vinyl selenide 1 to 2 took
place through the zwitterionic intermediate (or the transi-
tion state) 12, which could be generated by the nucleophilic
attack of the Pt(PPh3)2 fragment of p-complex 13 onto the
a-carbon (Scheme 2). Unlike the case of oxidative addition
of vinyl sulfide to 2, only one substituent with the a-anion
stabilization effect [11] was requisite at the b-carbon (A or
B) to realize this transformation at room temperature.
Finally, the C–Se bond was weakened by pushing anionic
charge at the b-carbon into the C–Se r* orbital after a min-
imum rotation about the C–C bond to form the transition
state (or the intermediate) 14, and then SeAr group was
migrated into coordination sphere of the platinum. During
the process, Y-shape structure constructed by two PPh3
and the Pt would be retained to afford cis-3 as a kinetic
product.
ð4Þ

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H. Kuniyasu et al. / Journal of Organometallic Chemistry 691 (2006) 1873–1878
Scheme 2. A proposed route of oxidative addition of 1 to 2.
3. Experimental
Then the solid was washed by hexane (10 mL · 3) and
dried to give cis-3a (553.3 mg, 92%). The good crystal of
cis-3a for X-ray crystallographic analysis was prepared
by recrystallization from benzene/hexane.
All reactions described in this paper were performed
1
under a N2 atmosphere. The 31P and H NMR spectra
were recorded with a JEOL JMN Alice-400 (160 and
400 MHz, respectively) spectrometer in C6D6 solution.
The chemical shifts of the 31P NMR spectra were recorded
relative to 85% H3PO4 (aq) as an external standard, and
S@P(C6H4OMe-p)3 was used as an internal standard to
calculate the yields of products. The chemical shifts in
cis-3a: m.p. 148 ꢀC (an yellow solid); 1H NMR
(400 MHz, C6D6) d 6.80–6.86 (m, 27 H), 7.25 (d,
J = 8.0 Hz, 2 H), 7.55–7.63 (m, 8 H), 7.70–7.74 (m, 5 H),
7.79 (d, J = 8.0 Hz, 2 H); 31P NMR (160 MHz, C6D6) d
17.4 (trans to C) (d, JP–P = 16 Hz, JPt–P = 1856 Hz), 17.8
(trans to Se) (d, JP–P = 16 Hz, JPt–P = 3280 Hz); IR
(KBr) 3051, 1472, 1435, 1088, 1010, 811, 744, 692, 538,
523, 487 cmꢀ1; Anal. Calc. for C56H44Cl2P2PtSe2: C,
55.92; H, 3.69. Found: C, 55.65; H, 3.74%.
1
the H NMR spectra were recorded relative to C6D6 (d
7.15). IR spectra were recorded with a Perkin Elmer FT-
IR (Model 1600) spectrometer. The X-ray crystal data of
cis-3a were collected by Rigaku RAXIS-RAPID Imaging
Plate diffractometer and the ORTEP drawing in Fig. 1
has been shown with 50% probability ellipsoids. Elemental
analyses were performed in the Instrumental Analysis Cen-
ter of the Faculty of Engineering, Osaka University. Vinyl
selenides (1a–d) were synthesized according to the litera-
ture (J. Am. Chem. Soc. 113 (1991) 9796/Synth. Commun.
26 (1996) 671/Tetrahedron 56 (2000) 1445). Vinyl sulfide 7
was also prepared according to the literature (J. Am.
Chem. Soc. 121 (1999) 5108). The platinum complex
Pt(PPh3)2(C2H4) (2) was synthesized according to the liter-
ature (Inorg. Synth. 18 (1978) 120). C6H6 and C6D6 were
purified by distillation from sodium benzophenon ketyl
before use.
3.2. Monitoring the solution of cis-3a
Into a dry Pyrex NMR tube were added cis-3a (25.0 mg,
0.021 mmol), S@P(C6H4OMe-p)3 (0.9 mg, 0.0024 mmol)
and C6D6 (0.5 mL) under a N2 atmosphere. The 31P
NMR spectrum taken after 22 h at 25 ꢀC showed the sig-
nals of 61% of cis-3a and 19% of trans-3a with some unas-
1
signable peaks. Its H NMR spectrum did not show the
liberation of phenyl acetylene, indicating that no b-SeAr
elimination took place from 3a.
trans-3a: 31P NMR (160 MHz, C6D6)d 19.3 (s, JPt–P
=
3004 Hz).
3.3. The reaction of 1b with 2 (Eq. (3))
3.1. The reaction of 1a with 2 (Eq. (2))
Into a dry Pyrex NMR tube were added 2 (15.0 mg,
0.020 mmol), 1b (13.4 mg, 0.028 mmol), S@P(C6H4OMe-
p)3 (1.6 mg, 0.0042 mmol) and C6D6 (0.5 mL) under a N2
atmosphere. Then the reaction was monitored by 31P and
1H NMR spectra at 25 ꢀC. The 31P NMR spectrum showed
the formation of cis-3b, trans-4 and 5. On the other hand, 1H
NMR spectrum showed the formation of 6. The reaction
Into a dry two-necked reaction vessel equipped with a
stirring bar were added 2 (373.9 mg, 0.50 mmol), 1a
(241.6 mg, 0.50 mmol) and C6H6 (20 mL) under a N2
atmosphere. After the reaction mixture was stirred at
25 ꢀC for 30 min, hexane (ca. 50 mL) was added into the
mixture and the precipitate was collected by filtration.

H. Kuniyasu et al. / Journal of Organometallic Chemistry 691 (2006) 1873–1878
1877
times and the yields of cis-3b, trans-4, 5 and 6 at the time
were 20 min, 55%, 21%, 11%, 25%; 1 h, 50%, 39%, 9%,
39%; 21 h, 0%, 92%, 0%, 83%.
was described in the supporting information of the paper
cited in Ref. [9]), was detected (3%) together with 2 (16%)
and 8 (60%).
cis-3b: 31P NMR (160 MHz, C6D6) d 14.4 (trans to C)
(d, JP–P = 17 Hz, JPt–P = 1781 Hz), 18.7 (trans to Se) (d,
JP–P = 17 Hz, JPt–P = 3395 Hz).
8: 31P NMR (160 MHz, C6D6) d 28.4 (d, JP–P = 42 Hz,
JPt–P = 3603 Hz), 29.5 (d, JP–P = 42 Hz, JPt–P = 3717 Hz).
trans-9: 31P NMR (160 MHz, C6D6) d 23.7 (s, JPt–P
=
1
6: H NMR (400 MHz, C6D6) d 0.10 (s, 9 H), 2.06 (s, 1
2988 Hz).
H).
3.7. The reaction of 1c with 2 (Eq. (5))
3.4. The preparation of 4
Into a dry Pyrex NMR tube were added 2 (15.4 mg,
0.021 mmol), 1c (6.5 mg, 0.022 mmol), S@P(C6H4OMe-
p)3 (1.1 mg, 0.0028 mmol) and C6D6 (0.5 mL) under a N2
atmosphere. Then the reaction was monitored by 31P and
1H NMR spectra at 25 ꢀC. The 31P NMR spectrum indi-
cated the formation of 10c and 3c, whose structure was ten-
tatively characterized by comparing the 31P NMR data
with those of 9. The reaction times and the yields of 10c
and 3c at the time were 20 h, 6%, 76% (cis/trans = 82/
18); 50 h, 0%, 68% (cis/trans = 53/47). When the sample
was additionally heated at 60 ꢀC for 5 h, the complete
isomerization of cis-3c to trans-3c (41%) was confirmed.
Into a dry two-necked reaction vessel equipped with a stir-
ring bar were added 2 (379.3 mg, 0.51 mmol), (p-ClC6H4Se)2
(202.2 mg, 0.53 mmol) and C6H6 (5 mL) under a N2 atmo-
sphere. After the reaction mixture was stirred at 25 ꢀC for
20 min, hexane (ca. 50 mL) was added into the mixture and
the precipitate was collected by filtration. The resultant solid
was washed by hexane (10 mL · 3) and then dried to give 4
(516.1 mg, 92%, cis/trans = 85/15). The stereochemistry of
two PPh3 on Pt was determined according to the 31P NMR
data (chemical shifts and the values of JPt–P) for
[Pt(SePh)2(PPh3)2] documented in Organometallics 22
(2003) 1414. 4 (the following data were collected from a mix-
10c: 31P NMR (160 MHz, C6D6) d 28.4 (d, JP–P
42 Hz, JPt–P = 3619 Hz), 29.8 (d, JP–P = 42 Hz, JPt–P
3695 Hz).
=
=
1
ture of stereoisomers): m.p. 208 ꢀC (an orange solid); H
NMR (160 MHz, C6D6) (cis isomer): d 7.54–7.59 (m, 12
H), 7.65 (d, J = 8.4 Hz, 4 H); (trans isomer): d 6.64 (d,
J = 8.4 Hz, 4 H), 7.74–7.76 (m, 12 H). Other peaks over-
lapped in the region of d 6.76–6.95 were not able to be read
distinctively.; 31P NMR (160 Hz, C6D6) (cis isomer): d 19.0
cis-3c: 31P NMR (160 MHz, C6D6) d 18.0 (trans to Se)
(d, JP–P = 16 Hz, JPt–P = 3194 Hz), 22.6 (trans to C) (d,
JP–P = 16 Hz, JPt–P = 1815 Hz).
trans-3c: 31P NMR (160 MHz, C6D6) d 23.6 (s, JPt–P
=
(s, JPt–P = 2935 Hz); (trans isomer): d 20.2 (s, JPt–P
=
2985 Hz).
2766 Hz); IR (KBr) 3078, 1465, 1433, 1090, 1009, 806, 743,
701, 539, 503 cmꢀ1; Anal. Calc. for C48H38Cl2P2PtSe2: C,
52.38; H, 3.48. Found: C, 52.71; H, 3.65%.
3.8. The reaction of 1d with 2 (Eq. (6))
Into a dry Pyrex NMR tube were added 2 (15.0 mg,
0.020 mmol), 1d (7.5 mg, 0.035 mmol), S@P(C6H4OMe-
p)3 (0.8 mg, 0.0022 mmol) and C6D6 (0.5 mL) under a N2
atmosphere. Then the reaction was monitored by 31P and
1H NMR spectra at 25 ꢀC. The 31P NMR spectrum taken
after 20 min showed the formation of 10d quantitatively.
No signal change was observed after 25 h. When the sam-
ple was additionally heated at 60 ꢀC for 5 h, signals of 10%
of suspected trans-3d (or 11) and 56% of 10d were detected.
3.5. The confirmation of 5
Into a dry Pyrex NMR tube were added 2 (15.4 mg,
0.021 mmol),
6 (7.2 mg, 0.0733 mmol), S@P(C6H4O-
Me-p)3 (0.5 mg, 0.0013 mmol) and C6D6 (0.5 mL) under a
N2 atmosphere. The 31P NMR spectrum taken after
20 min at 25 ꢀC showed the formation of 5 in 97% yield
with 3% of 2.
1
5: P NMR (160 MHz, C6D6) d 29.0 (d, JP–P = 47 Hz,
10d: 31P NMR (160 MHz, C6D6) d 31.6 (d, JP–P
43 Hz, JPt–P = 3626 Hz), 31.9 (d, JP–P = 43 Hz, JPt–P
3612 Hz).
=
=
JPt–P = 3758 Hz), 32.5 (d, JP–P = 47 Hz, JPt–P = 3672 Hz).
3.6. The reaction of 7 with 2 (Eq. (4))
trans-3d (or 11): 31P NMR (160 MHz, C6D6) d 23.9 (s,
JPt–P = 3025 Hz).
Into a dry Pyrex NMR tube were added 2 (14.5 mg,
0.019 mmol), 7 (5.8 mg, 0.024 mmol), S@P(C6H4OMe-p)3
(0.7 mg, 0.0019 mmol) and C6D6 (0.5 mL) under a N2 atmo-
sphere. Then the reaction was monitored by the 31P and 1H
NMR spectra at 25 ꢀC. The 31P NMR spectrum after 20 min
showed the formation of 8 in 78% yield with the recovery of
22% of 2. When the sample was additionally heated at 60 ꢀC
for 5 h, the signal of oxidative addition product trans-9,
whose structure has been assigned by comparing the spec-
trum data with those of authentic sample (The spectral data
4. Supplementary material
CCDC 287189 contains the supplementary crystallo-
graphic data for this paper (cis-3a). These data can be
obtained free of charge via www.ccdc.cam.ac.uk/dataf_re-
quest/cif, The Director, CCDC, 12, Union Road, Cam-
bridge CB2 1EZ, UK (fax: +44 1223 336033; e-mail:
deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).

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H. Kuniyasu et al. / Journal of Organometallic Chemistry 691 (2006) 1873–1878
(g) C.J. White, R.J. Angelici, M. Choi, Organometallics 14 (1995)
Acknowledgements
332.
[3] L. Han, N. Choi, M. Tanaka, J. Am. Chem. Soc. 119 (1997)
1795.
[4] (a) H. Okamura, M. Miura, K. Kosugi, H. Takei, Tetrahedron Lett.
21 (1980) 87;
The authors gratefully acknowledge Dr. Nobuko
Kanehisa of Osaka University for an X-ray structure anal-
ysis. Thanks are due to the Instrumental Analysis Center,
Faculty of Engineering, Osaka University, for elemental
analyses.
(b) L. Hevesi, B. Hermans, C. Allard, Tetrahedron Lett. 35 (1994)
6729;
(c) M. Tingoli, M. Tiecco, L. Testaferri, A. Temperini, G. Pelizzi, A.
Bacchi, Tetrahedron 51 (1995) 4691;
References
(d) J. Gerard, L. Hevesi, Tetrahedron 57 (2001) 9109.
[5] (a) T. Hirai, H. Kuniyasu, T. Kato, Y. Kurata, N. Kambe, Org.
Lett. 5 (2003) 3871;
[1] (a) J.P. Collman, L.S. Hegedus, J.R. Norton, R.G. Finke, Principles
and Application of Organotransition-Metal Chemistry, University
Science Books, Mill Valley, CA, 1987;
(b) H. Kuniyasu, A. Ogawa, K. Higaki, N. Sonoda, Organometallics
11 (1992) 3937.
(b) R.H. Crabtree, The Organometallic Chemistry of the Transition
Metals, fourth ed., Wiley-Interscience, New York, 2005.
[2] (a) K. Yu, H. Li, E.J. Watson, K.L. Virkaitis, G.B. Carpenter, D.A.
Sweigart, Organometallics 20 (2001) 3550;
[6] H. Kuniyasu, A. Ohtaka, T. Nakazono, M. Kinomoto, H. Kurosawa,
J. Am. Chem. Soc. 122 (2000) 2375.
[7] H. Kuniyasu, A. Ogawa, S. Miyazaki, I. Ryu, N. Kambe, N. Sonoda,
J. Am. Chem. Soc. 113 (1991) 9796.
(b) D.A. Vicic, A.W. Myers, W.D. Jones, Organometallics 16 (1997)
2751;
[8] K. Osakada, K. Matsumoto, T. Yamamoto, A. Yamamoto, Organo-
metallics 4 (1985) 857.
(c) D.S. Choi, I.S. Lee, S.U. Son, Y.K. Chung, Organometallics 20
(2001) 3617;
[9] P.A. Chaloner, S.E. Davies, P.B. Hitchcock, J. Organomet. Chem.
527 (1997) 145.
(d) M.G. Choi, R.J. Angelici, J. Am. Chem. Soc. 113 (1991) 5651;
(e) A.J. Arce, R. Machado, C. Rivas, Y.D. Sanctis, J. Organomet.
Chem. 419 (1991) 63;
(f) A.J. Arce, A.J. Deeming, Y.D. Sanctis, R. Machado, J. Manzur,
C. Rivas, J. Chem. Soc., Chem. Commun. (1990) 1568;
[10] A. Ohtaka, H. Kuniyasu, M. Kinomoto, H. Kurosawa, J. Am.
Chem. Soc. 124 (2002) 14324.
[11] F.G. Bordwell, J.E. Bares, J.E. Bartmess, G.J. McCollum,
M.V.D. Puy, N.R. Vanier, W.S. Matthews, J. Org. Chem. 42
(1977) 321.