Reactions of α,β-unsaturated thioesters with platinum(0): Implication of a dual mechanism leading to the formation of acyl platinum

Article abstract of DOI:10.1021/om050834w

The moderate reactivity of the α,β-unsaturated thioester (ArS)C(O)C(A)=C(B)(H) toward Pt(PPh₃)₂-(C ₂H₄) has been used to extract thermodynamic and kinetic information pertaining to the oxidative addition of α,β-unsaturated acid halide derivatives to low-valent transition-metal complexes. The results indicate acyl platinum product complexes can form by direct C-S bond cleavage or by attack of coordinated Pt(PPh₃)₂ on the β-carbon.

Full text of DOI:10.1021/om050834w

Organometallics 2006, 25, 2949-2959
2949
Reactions of r,â-Unsaturated Thioesters with Platinum(0):
Implication of a Dual Mechanism Leading to the Formation of Acyl
Platinum†
Yasunori Minami, Tomohiro Kato, Hitoshi Kuniyasu,* Jun Terao, and Nobuaki Kambe*
Department of Molecular Chemistry & Frontier Research Center, Graduate School of Engineering,
Osaka UniVersity, Suita, Osaka 565-0871, Japan
ReceiVed September 28, 2005
The moderate reactivity of the R,â-unsaturated thioester (ArS)C(O)C(A)dC(B)(H) toward Pt(PPh3)2-
(C2H4) has been used to extract thermodynamic and kinetic information pertaining to the oxidative addition
of R,â-unsaturated acid halide derivatives to low-valent transition-metal complexes. The results indicate
acyl platinum product complexes can form by direct C-S bond cleavage or by attack of coordinated
Pt(PPh3)2 on the â-carbon.
that such characteristics could be utilized for elucidating the
mechanism of cleavage of the vinyl-X bonds by low-valent
transition-metals4 and for achieving a series of Pt-catalyzed
carbothiolation of alkynes.5 Herein we wish to report that the
effects of substituents on the reactions of R,â-unsaturated acid
halide derivatives with low-valent transition-metal complexes
are quite clearly revealed by utilizing the controllable reactivity
of the R,â-unsaturated thioester (ArS)C(O)C(A)dC(B)(H) (4)
toward 2, substantiating that there are two distinct reaction routes
for the formation of acyl complexes.
Introduction
It has been well-known that the reactions of R,â-unsaturated
acid halides with low-valent transition-metal complexes pro-
duced acyl metals.1 However, much attention to their reaction
mechanism has not been attracted presumably due to the lack
of a good reaction system to examine the details. In fact, when
the reactions of (Cl)C(O)C(H)dCH2 (A ) B ) H; 1a) or (Cl)C-
(O)C(H)dC(Ph)(H)-(E) (A ) H, B ) Ph; 1b) with Pt(PPh3)2-
(C2H4) (2) were performed in toluene-d8 using a freeze-pump-
thaw technique, acyl platinums 3a and 3b were quantitatively
produced even at -50 °C after 10 min in both cases (eq 1).2
Although the predominant formation of the cis isomer at the
Results and Discussion
Reactions of Thioesters Having a p-MeC6H4S Group with
a Platinum(0) Complex. Thioesters 4 with a p-MeC6H4S group
shown in Table 1 were prepared, and the reactions with 2 were
1
monitored by H and 31P NMR spectroscopies at 25 °C using
SdP(C6H4OMe-p)3 as an internal standard.6 When 4a (A ) B
) H) was employed, the quantitative formation of π-complex
5a was confirmed after 20 min in both C6D6 and CD2Cl2
solution. Although it was not clear when the systems reached
the equilibrium states due to the low yields of acyl platinum 6a
and 7a (dimeric form of 6a), the formation after 3 h of 99.5%
of 5a and 0.5% of 7a in C6D6 and of 98.9% of 5a, 0.4% of 6a,
and 0.7% of 7a was confirmed in CD2Cl2 (runs 1 and 2). On
the other hand, the reaction of trans-3a (0.02 mmol) with
p-MeC6H4SNa (8, 0.06 mmol) in CD2Cl2 (0.5 mL) at 25 °C
produced 5a (79%), trans-6a (0.6%), and 7a (13%, syn/anti )
77/23) after 17 h (eq 2). These results clearly showed that the
beginning of the reactions suggested its stereochemistry of
oxidative addition, more information such as the effect of the
introduction of a Ph group at the â-carbon (B ) Ph) was not
clearly disclosed from these experimental data.
Recently, we have reported that the cleavage and formation
of C-S bonds by transition-metal complexes were flexible3 and
† This work is dedicated to Prof. Hideo Kurosawa on the occasion of
his retirement from Osaka University.
* To whom correspondence should be addressed. E-mail:
kuni@chem.eng.osaka-u.ac.jp.
(4) (a) Kuniyasu, H.; Ohtaka, A.; Nakazono, T.; Kinomoto, M.; Kuro-
sawa, H. J. Am. Chem. Soc. 2000, 122, 2375. (b) Kuniyasu, H.; Kato, T.;
Inoue, M.; Terao, J.; Kambe, N. J. Organomet. Chem. 2006, 691, 1873.
(5) (a) Sugoh, K.; Kuniyasu, H.; Sugae, T.; Ohtaka, A.; Takai, Y.;
Tanaka, A.; Machino, C.; Kambe, N.; Kurosawa, H. J. Am. Chem. Soc.
2001, 123, 5108. (b) Kuniyasu, H.; Kurosawa, H. Chem. Eur. J. 2002, 12,
2660. (c) Hirai, T.; Kuniyasu, H.; Kato, T.; Kurata, Y.; Kambe, N. Org.
Lett. 2003, 5, 3871. (d) Hirai, T.; Kuniyasu, H.; Kambe, N. Chem. Lett.
2004, 33, 1148. (e) Hirai, T.; Kuniyasu, H.; Kambe, N. Tetrahedron. Lett.
2005, 46, 117. (f) Hirai, T.; Kuniyasu, H.; Terao, J.; Kambe, N. Synlett.
2005, 7, 1161. (g) Kuniyasu, H.; Yamashita, F.; Hirai, T.; Ye, J.; Fujiwara,
S.; Kambe, N. Organometallics 2006, 25, 566.
(1) (a) Collman, J. P.; Hegedus, L. S.; Norton, J. R.; Finke, R. G.
Principles and Applications of Organotransition-Metal Chemistry; Univer-
sity Science Books: Mill Valley, CA, 1987. (b) Grabtree, R. H. The
Organometallic Chemistry of the Transition Metals, 4th ed.; Wiley-
Interscience: New York, 2003.
(2) (a) Stille, J. K.; Lau, K. S. Y. Acc. Chem. Res. 1977, 10, 434. (b)
Fahey, D. R.; Mahan, J. E. J. Am. Chem. Soc. 1977, 99, 2501. (c) Dent, S.
P.; Eaborn, C.; Pidcock, A. J. Organomet. Chem. 1975, 97, 307.
(3) (a) Kuniyasu, H.; Sugoh, K.; Moon, S.; Kurowasa, H. J. Am. Chem.
Soc. 1997, 119, 4669. (b) Miyauchi, Y.; Watanabe, S.; Kuniyasu, H.;
Kurosawa, H. Organometallics 1995, 14, 5450.
(6) No interaction between SdP(C6H4OMe-p)3 and other reagents has
been confirmed during the course of the present study.
10.1021/om050834w CCC: $33.50 © 2006 American Chemical Society
Publication on Web 05/11/2006

2950 Organometallics, Vol. 25, No. 12, 2006
Minami et al.
Table 1. Reactions of 4 with 2a
run
4
solventb
timec
5/6(cis/trans)d
timee
6(cis/trans)/7(syn/anti)d
f
f
g
f
f
g
h
1
2
3
4
5
6
7
8
9
4a
4a
4b
4b
4c
4c
4d
4e
4f
4f
4f
4g
4g
4g
a
b
a
b
a
b
a
a
a
a
b
a
a
b
-
-
-
-
-
-
-
-
h
3-4 h
5-6 h
<40 min
<40 min
9-10 h
52-55 h
14-15 h
14-15 h
16-17 h
<40 min
<40 min
<40 min
51/49(6/94)
22/78(13/87)
57/43(0/100)
17/83(0/100)
78/22(0/100)
81/19(0/100)
71/29(0/100)
68/32(0/100)
50/50(21/79)
89/11(0/100)
91/9(0/100)
70/30(0/100)
3-4 h
5-6 h
<40 min
<40 min
3-6 h
10-15 h
9-10 h
7-8 h
13-14 h
<40 min
<40 min
60-80 min
13(6/94)/87(79/21)
22(13/87)/78(83/17)
7(0/100)/93(64/36)
20(0/100)/80(74/26)
7(0/100)/93(74/26)
6(0/100)/94(81/19)
9(0/100)/91(76/24)
10(0/100)/90(74/26)
18(19/81)/82(86/14)
8(0/100)/92(60/40)
7(0/100)/93(63/37)
15(0/100)/85(70/30)
10i
11
12
13j
14
a 2 (0.020 mmol), 4 (0.022 mmol) under N2 atmosphere at 25 °C. b a, C6D6; b, CD2Cl2. c Required to reach the equilibrium of 5/6. d Ratio at equilibrium.
e Required to reach the equilibrium of 6/7. f It was not clear when equilibrium was reached. g 99.5% of 5a and 0.5% of 7a after 3 h. h 98.9% of 5a, 0.4%
of 6a, and 0.7% of 7a after 3 h. i 4.3 equiv of 4f. j 4.8 equiv of 4g.
5/6 in these reaction systems (3-6 h vs 9-10 h in run 7 and
10-15 h vs 52-55 h in run 8). Although a larger thermody-
namic driving force toward the oxidative addition from 5 to 6
was supplied by placing Ph at A compared to Ph at B (5f/6f )
equilibrium between 5a and 6a strongly leaned to the former
71/29 of run 9 vs 5g/6g ) 89/11 of run 12 in C6D6 or 5f/6f )
side. When 4b (A ) Me, B ) H) was employed, the signal of
50/50 of run 11 vs 5g/6g ) 70/30 of run 14 in CD2Cl2), a much
starting 2 also completely disappeared and the formation of a
more prolonged time was again required to reach the equilibria;
mixture of the corresponding 5b, 6b, and 7b was confirmed in
only <40 min were required for 5g/6g in both C6D6 and CD2-
Cl2 (runs 12 and 14), while the systems of 5f/6f came to
equilibria during 14-15 h and 16-17 h, after the equilibria of
6f/7f were achieved during the period of 9-10 h and 13-14 h,
respectively (runs 9 and 11). Although there are the plural
equilibrium systems such as 6/7, cis-6/trans-6, and syn-7/anti-
7, all the results above indicate that introducing a bulky
substituent at A causes retardation of the process of conversion
of 5 into 6. The reactions performed in the presence of an excess
amount of 4 toward 2 (runs 10 and 13) in the case of A ) Ph
or B ) Ph showed no practical influence on both the reaction
rates and the positions of equilibria, indicating that the genera-
78%, 4.4% (cis/trans ) 9/91), and 17% (syn/anti ) 47/53) yields
after 20 min in C6D6 and in 66%, 20% (cis/trans ) 45/55), and
14% (syn/anti ) 51/49) yields in CD2Cl2. Monitoring the
reactions by 31P NMR spectra suggested that 6b and 7b were
produced via 5a and revealed that the equilibria among 5b, 6b,
and 7b were attained in the periods of 3-4 h in C6D6 and 5-6
h in CD2Cl2 (runs 3 and 4).7,8 The reactions using 4c (A ) H,
B ) Me) also showed the formation of 5c, 6c, and 7c after 20
min. It must be noted that the transformation from 5c into 6c
and 7c was much faster than that from 5b into 6b and 7b; the
equilibria were attained within 40 min (runs 5 and 6). The
foregoing facts demonstrate that the reaction systems of 4,
possessing p-MeC6H4S, with 2 are quite flexible and the position
changes of the equilibrium states caused by substituents and
solvents are readily analyzable.
tion of 6 from 5 is a unimolecular process. The chart of the 31
P
NMR spectrum of the reaction of 4c (A ) H, B ) Me) with 2
in toluene-d8 attempted at a low reaction temperature (-70 °C
after 10 min) suggested the formation of two π-complexes at
(a) δ 29.9 (d, JP-P ) 44 Hz, JPt-P ) 4208 Hz) and δ 31.2 (d,
JP-P ) 44 Hz, JPt-P ) 3373 Hz) and (b) δ 29.4 (d, JP-P ) 41
Furthermore, the comparison of the equilibria of 5b/6b )
51/49 (run 3) with 5c/6c ) 57/43 (run 5) in C6D6 or 5b/6b )
22/78 (run 4) with 5c/6c ) 17/83 (run 6) in CD2Cl2 indicates
that the slow conversion of 5b into 6b and 7b is not attributable
to its thermodynamics. Moreover, it took 9-10 h and even 52-
55 h to reach the equilibrium states between 5 and 6 when 4d
(A ) n-C6H13, B ) H) and 4e (A ) i-Pr, B ) H) were employed
as starting substrates, respectively (runs 7 and 8). It is also a
noteworthy fact that 6/7 reached equilibrium states faster than
Hz, JPt-P ) 3280 Hz) and δ 30.1 (d, JP-P ) 41 Hz, JPt-P
)
4212 Hz) in a ratio of 63/37 in 19% yields (eq 3), although the
(7) The reactions were continuously monitored until the equilibria were
fully achieved.
(8) Zhang, X.; Yu, K.; Carpenter, G. B.; Sweigart, D. A.; Czech, P. T.;
D’Acchioli, J. S. Organometallics 2000, 19, 1201.

Reactions of R,â-Unsaturated Thioesters with Pt(0)
Organometallics, Vol. 25, No. 12, 2006 2951
Scheme 1. Proposed Pathway from 5 to 6
Table 2. Half-Lives from 5 to 6a
stereochemistry was not able to be determined from these
spectral data.9 Then the ratio of the latter signal decreased at
-10 °C (96/4) and completely disappeared at 0 °C. Eventually,
7c was produced as a major product at 25 °C. Only the trans
isomer of 6c was detected during the course of this reaction.
On the other hand, the reaction utilizing 4g (A ) H, B ) Ph)
produced only one π-complex in 22% yield at -50 °C (eq 4).
In this case, however, cis-6g was also detected at -30 °C (5%
with cis/trans ) 60/40) and trans-6g (4%) was again finally
produced, indicating cis-6g was generated as a kinetic product.
run
4
solvent
t
1/2 (min) run
4
solvent
t1/2 (min)
1
2b
3
4
5
6
7
8
4h C6D6
4h C6D6
4h CD2Cl2
4h acetone-d6
4h THF-d8
38
36
14
19
36
2.1
3.3
43
9c
4j
4j
C6D6
CD2Cl2
43
10
11
12
13
6.8
6.2
1.2
9.1
9.1
7.8
4k C6D6
4k CD2Cl2
4l
C6D6
C6D6
CD2Cl2
4i
4i
4j
C6D6
CD2Cl2
C6D6
14d 4l
15
4l
a 2 (0.020 mmol), 4 (0.022 mmol) under N2 atmosphere at 25 °C. trans-6
was finally predominantly produced. b 4.5 equiv of 4h. c 5.0 equiv of 4j.
d 4.7 equiv of 4l.
The foregoing experimental data can be rationalized as
follows (path a of Scheme 1). After the formation of π-complex
5, the coordinated Pt(PPh3)2 fragment would approach the C-S
bond with the π-coordination partially retained.10 During the
process, two PPh3’s on Pt would remain cis-coordinated,4 bulky
substituents at A significantly slow the reaction owing to steric
hindrance, and the cleavage of the C-S bond and the formation
of C-Pt and S-Pt bonds take place through a transition state
such as 8, which can possess a polarity comparable to 5.
Other Observations. The foregoing data (Table 1) also
clearly showed the following. (1) The positions of equilibria of
5/6 and 6/7 both were slightly shifted toward 6 by changing
the solvent from C6D6 to CD2Cl2. (Compare 51/49 of run 3
with 22/78 of run 4 for 5b/6b and 13/87 of run 3 with 22/78 of
run 4 for 6b/7b for instance.) That is, the conversion from 5
into 6 was thermodynamically facilitated to some degree by a
polar solvent and 6 has a slightly larger dipole moment than 7.
(2) The formation of cis-6 was confirmed when thioesters having
the substituent at A were employed (runs 3-4 and 11), and the
ratio of cis-6 to trans-6 was increased by changing the solvent
from C6D6 to CD2Cl2. (Compare 6/94 of run 3 with 13/87 of
run 4 and 0/100 of run 9 with 21/79 of run 11.) (3) The positions
of equilibria between 6 and 7 were hardly influenced by the
substituent at A or B. The ratios of 6/7 were all in the narrow
range from 6/94 (run 8) to 13/87 (run 3) in C6D6 and from 15/
85 (run 14) to 22/78 in CD2Cl2 (run 4), indicating that the
basicity of the lone pair on sulfur, which can be mainly
controlled by the substituent in Ar (vide infra), was the
predominant factor to determine the position of equilibria
between 6 and 7.11 (4) The fact that the formation of syn-7 over
anti-7 was increased by changing the solvent from C6D6 to CD2-
Cl2 agrees with the prediction that the dipole moment of syn-7
is slightly larger than that of anti-7.
Reactions of Thioesters Having a p-NO2C6H4S Group with
a Pt(0) Complex. It was found that more clear kinetic data from
5 to 6 were acquired by using thioesters with a p-NO2C6H4S
group; monitoring the reactions of 2 with 4 shown in Table 2
demonstrated that 6 was exclusively produced from 5, whose
decay followed first-order kinetics. The fact that complexes 7
were hardly detected in these reactions (<1%) also supports
the proposition that introduction of electron-withdrawing NO2
group lowered the basicity of lone pairs on sulfur, resulting in
the prevention of the formation of 7.11 When 4h (A ) Me, B )
H) was employed, the half-life of 5h forming 6h was calculated
to be 38 min in C6D6 (run 1). As predicted from the results of
Table 1, the introduction of Me at B kinetically facilitated the
reaction (run 6, t1/2 ) 2.1 min). In stark contrast, the reaction
of 4j, having an i-Pr group at A, which significantly retarded
the reaction in the case of ArS ) p-MeC6H4S (run 8 in Table
1), took place at a reaction rate comparable with that employing
4h (t1/2 ) 43 min of run 8 vs t1/2 ) 38 min of run 1). Moreover,
(9) It has been already reported that the X-ray crystallographic structure
of Pt[(PhH2CO)(O)C(H)CdCH2](PPh3)2 showed the s-cis configuration for
the CdO and CdC moieties. Chaloner, P. A.; Davies, S. E.; Hitchcock, P.
B. J. Organomet. Chem. 1997, 527, 145.
(10) (a) Strawser, D.; Karton, A.; Zenkina, O. V.; Iron, M. A.; Shimon,
L. J. W.; Martin, J. M. L.; Boom, M. E. J. Am. Chem. Soc. 2005, 127,
9322. (b) Yu, K.; Li, H.; Watson, E. J.; Virkaitis, K. L.; Carpenter, G. B.;
Sweigart, D. A. Organometallics 2001, 20, 3550.
(11) (a) Jones, W. D.; Reynolds, K. A.; Sperry, C. K.; Lachicotte, R. J.;
Godleski, S. A.; Valente, R. R. Organometallics 2000, 19, 1661. (b) Boschi,
T.; Crociani, B.; Toniolo, L.; Belluco, U. Inorg. Chem. 1970, 9, 532.

2952 Organometallics, Vol. 25, No. 12, 2006
Minami et al.
Table 3. Activation Parameters from 5h to 6h, from 5j to 6j,
and 5h from 6h
although retardation was also expected by introducing Ph at A
(vide ante), the transformation of 5k (A ) Ph, B ) H) to 6k
was actually faster than that of 5l (A ) H, B ) Ph) to 6l (6.2
min of run 11 vs 9.1 min of run 13). The effect of solvent was
also very intriguing. While the reaction rates were hardly
influenced by the polarity of the solvent in the cases of substrates
possessing a substituent at B [2.1 min in C6D6 (run 6) vs 3.3
min in CD2Cl2 (run 7) for 5i to 6i or 9.1 min in C6D6 (run 13)
vs 7.8 min in CD2Cl2 (run 15) for 5l to 6l], significant
acceleration was detected in CD2Cl2 solution with the thioesters
having a substituent at A. The reactions took place 2.7 times
faster for 5h (38 min in C6D6 of run 1 vs 14 min in CD2Cl2 of
run 3), 6.3 times faster for 5j (43 min in C6D6 of run 8 vs 6.8
min in CD2Cl2 of run 10), and 5.2 times faster for 5k (6.2 min
in C6D6 of run 11 vs 1.2 min in CD2Cl2 of run 12). The reaction
performed in acetone-d6 also proceeded faster than that in C6D6
(19 min of run 4 vs 38 min of run 1), while no facilitation was
observed in THF-d8 (36 min of run 5). Similarly to the cases of
reactions shown in Table 1, the reaction rates were independent
of the excess amount of 4 in the cases of thioesters with
substituents at either the A or B position [run 1 vs run 2 (4.5
equiv of 4h), run 8 vs run 9 (5.0 equiv of 4j), and run 13 vs
run 14 (4.7 equiv of 4l)]. When the reaction of 4k with 2 was
performed at low reaction temperature, selective formation of
5k was confirmed at -50 °C after 10 min in 70% yield (eq 5).
from 5h to 6h (A ) Me, B ) H)
in C6D6
in CD2Cl2
∆Gq ) 93.0 ( 0.1 kJ mol-1
∆Hq ) 95.3 ( 0.4 kJ mol-1
∆Sq ) 7.5 ( 1.4 J K-1mol-1
∆Gq ) 90.5 ( 0.1 kJ mol-1
∆Hq ) 53.5 ( 0.1 kJ mol-1
∆Sq ) -124.4 ( 0.2 J K-1mol-1
from 5j to 6j (A ) i-Pr, B ) H)
in C6D6
in CD2Cl2
∆Gq ) 93.4 ( 0.1 kJ mol-1
∆Hq ) 78.7 ( 0.1 kJ mol-1
∆Sq ) 049.2 ( 0.3 J K-1mol-1
∆Gq ) 88.9 ( 0.1 kJ mol-1
∆Hq ) 40.2 ( 0.2 kJ mol-1
∆Sq ) -163.5 ( 0.5 J K-1mol-1
from 5l to 6l (A ) H, B ) Ph)
in C6D6
in CD2Cl2
∆Gq ) 89.8 ( 0.1 kJ mol-1
∆Hq ) 68.2 ( 0.7 kJ mol-1
∆Sq ) -72.5 ( 2.4 J K-1mol-1
∆Gq ) 89.5 ( 0.1 kJ mol-1
∆Hq ) 81.9 ( 1.9 kJ mol-1
∆Sq ) -25.5 ( 6.4 J K-1mol-1
proceed faster than that utilizing 4h (run 3 vs run 10 in Table
2). The reaction using a thioester with p-NO2C6H4S and Ph
groups at A would overwhelmingly occur via path b even in
C6D6 solution due to the R-anion stabilization ability of Ph as
well as the steric repulsion between Ph and the Pt(PPh3)2
fragment. This is why the reaction of 4k took place faster than
that of 4l even in C6D6 (run 11 vs run 13 in Table 2). After the
generation of 9, the Pt(PPh3)2 fragment would migrate from the
â-carbon to the carbonyl carbon through an η1-η3-η1 type
isomerization mechanism. During the process, the two PPh3’s
on Pt also would retain a cis configuration to give cis-6 as a
kinetic product, which would isomerize into the thermodynami-
cally more stable trans-6.
To obtain more convincing information about the reaction
mechanism, the activation parameters of the transformation of
6 from 5 were calculated by measuring the temperature
dependence of the reaction rates (20-40 °C), and values of ∆Gq,
∆Hq, and ∆Sq are shown in Table 3. The following facts must
be noted. First, the activation parameters of the formation of
6h from 5h in C6D6 significantly differed from those in CD2-
Cl2. That is, while ∆Hq and ∆Sq in C6D6 were 95.3 ( 0.4 kJ
mol-1 and 7.5 ( 1.4 J K-1mol-1, those in CD2Cl2 were 53.5 (
0.1 kJ mol-1 and -124.4 ( 0.2 J K-1mol-1. The large negative
∆Sq and relatively small positive ∆Hq in CD2Cl2 did not
contradict the assumption that this reaction generates zwitterionic
platinum complex 9, where the degree of freedom of the total
reaction system was significantly diminished by a polar solvent
and stiff Pt-C bond formation. On the contrary, the more
positive ∆Sq and larger ∆Hq in C6D6 suggested the loss of bond
energy and only weak bond generation at the transition state.
Supposing that the π-coordination and C-S bond were weak-
ened and emerging C-Pt and S-Pt bonds were both not strong,
the transition state 8 would fulfill these criteria. Second, the
negative value of ∆Sq (-49.2 ( 0.3 J K-1 mol-1) from 5j to 6j
even in C6D6 also did not contradict the projection that this
reaction can also proceed through path b even in C6D6 solution.
That is, due to the significant steric hindrance caused by i-Pr
located at A, the route of path b competitively took place. The
small positive ∆Hq and large negative ∆Sq in CD2Cl2 also
accorded with the route of path b. Third, comparing the data of
formation of 6l from 5l in C6D6 with those in CD2Cl2,
differences in the values of ∆Hq and ∆Sq as well as half-lives
were much smaller than other cases. This can be nicely
rationalized by assuming that reactions in both C6D6 and CD2-
Cl2 took place through a similar reaction route, namely, the
Then cis-6k was produced at -40 °C after 10 min in 3% yield
and trans-6k was quantitatively provided at 25 °C.
Unlike the cases of reactions of thioesters possessing a
p-MeC6H4S group with 2, the above experimental data can be
rationalized by assuming that the Pt(PPh3)2 fragment can also
attack the â-carbon (path b of Scheme 1) as well as the direct
C-S bond attack (path a).12 The â-attack would generate
zwitterionic platinum complex 9, having an anionic charge
delocalized over the R-carbon and carbonyl group. The forma-
tion of 9 can be facilitated to a great extent by a polar solvent
and a substituent with R-anion stabilization ability such as a
Ph group at A.13 The steric repulsion caused between a
substituent at A and the Pt(PPh3)2 fragment would facilitate the
â-attack by pushing out the Pt(PPh3)2 fragment toward a less
hindered â-carbon in path b. Presumably due to the cancellation
by the retardation of path a and facilitation of path b by replacing
Me with i-Pr at A, no remarkable difference emerged in the
half-lives of 5 between the reactions using 4h and 4j in C6D6
(run 1 vs run 8 in Table 2). On the other hand, path b would
predominate in CD2Cl2 and the reaction utilizing 4j would
(12) It has been reported that R,â-unsaturated thioesters were employed
as excellent acceptors of Michael additions. Mazery, R. D.; Pullez, M.;
Lo´pez, F.; Harutyunyan, S. R.; Minnaard, A. J.; Feringa, B. L. J. Am. Chem.
Soc. 2005, 127, 9966, and references therein.
(13) It has been known that a substituent with an R-anion stabilization
effect at the R-carbon facilitated the Michael addition of a nucleophile to
R,â-unsaturated compounds. (a) Stork, G.; Ganem, B. J. Am. Chem. Soc.
1973, 95, 6152. (b) Holton, R. A.; Williams, A. D.; Kennedy, R. M. J.
Org. Chem. 1986, 51, 5480. (c) Gawley, R. E. Synthesis 1976, 777. (d)
Cooke, M. P., Jr. J. Org. Chem. 1987, 52, 5729.

Reactions of R,â-Unsaturated Thioesters with Pt(0)
Organometallics, Vol. 25, No. 12, 2006 2953
Scheme 2 Comparison of Oxidative Addition of Allyl-X to
NMR (400 MHz, CDCl3) δ 2.00 (s, 3 H), 2.37 (s, 3 H), 5.67 (s, 1
H), 6.19 (s, 1 H), 7.22 (d, J ) 8.0 Hz, 2 H), 7.31 (d, J ) 8.0 Hz,
2 H); 13C NMR (100 MHz, CDCl3) δ 18.4, 21.5, 123.5, 123.9,
129.8, 134.7, 139.4, 143.3, 191.6; mass spectrum (EI) m/z 192 (M+,
16); HRMS calcd for C11H12OS 192.0609, found 192.0611. 4c:
colorless oil; 1H NMR (400 MHz, CDCl3) δ 1.88 (dd, J ) 1.6 Hz,
J ) 7.0 Hz, 3 H), 2.36 (s, 3 H), 6.19 (dd, J ) 1.6 Hz, J ) 15.2 Hz,
1 H), 6.97 (dt, J ) 7.2 Hz, J ) 14.7 Hz, 1 H), 7.20 (d, J ) 8.0 Hz,
2 H), 7.31 (d, J ) 8.0 Hz, 2 H); 13C NMR (100 MHz, CDCl3) δ
18.1, 21.4, 123.8, 129.1, 129.7, 134.3, 139.2, 141.5, 187.8; mass
spectrum (EI) m/z 192 (M+, 10); HRMS calcd for C11H12OS
192.0609, found 192.0613. 4d: colorless oil; 1H NMR (400 MHz,
CDCl3) δ 0.88 (t, J ) 6.6 Hz, 3 H), 1.29 (br, 6 H), 1.44-1.49 (m,
2 H), 2.34 (t, J ) 7.6 Hz, 2 H), 2.38 (s, 3 H), 5.64 (s, 1 H), 6.20
M with That of r,â-Unsaturated Acid Halide Derivatives to
M
direct C-S bond attack of a Pt(PPh3)2 fragment (path a) from
a π-complex.
(s, 1 H), 7.22 (d, J ) 8.0 Hz, 2 H), 7.31 (d, J ) 8.0 Hz, 2 H); 13
C
NMR (100 MHz, CDCl3) δ 14.2, 21.5, 22.7, 28.3, 29.0, 31.7, 32.1,
122.4, 124.1, 129.8, 134.7, 139.4, 148.2, 191.9; mass spectrum (EI)
m/z 262 (M+, 14); HRMS calcd for C16H22OS 262.1391, found
Conclusion
When the reaction mechanism of oxidative addition of allylic
halide derivatives to low-valent transition-metal complexes to
generate π-allyl metals is considered, it has been well-
established that there are two reaction routes, syn- and anti-
oxidative addition (Scheme 2).14 This study suggested that even
when the substrates are R,â-unsaturated acid halide derivatives,
two distinct reaction routes can similarly exist. The generality
of this dual mechanism is now under investigation.
1
262.1393. 4e: colorless oil; H NMR (400 MHz, CDCl3) δ 1.11
(d, J ) 6.8 Hz, 6 H), 2.85 (sept, J ) 6.8 Hz, 1 H), 5.63 (s, 1 H),
6.18 (s, 1 H), 7.23 (d, J ) 8.2 Hz, 2 H), 7.32 (d, J ) 8.2 Hz, 2 H);
13C NMR (100 MHz, CDCl3) δ 21.3, 21.5, 29.9, 119.7, 124.1, 129.6,
134.5, 139.2, 154.3, 192.2; mass spectrum (EI) m/z 220 (M+, 16);
HRMS calcd for C13H16OS 220.0922, found 220.0923. 4f: white
1
solid; H NMR (400 MHz, CDCl3) δ 2.38 (s, 3 H), 5.87 (s, 1 H),
6.29 (s, 1 H), 7.22-7.45 (m, 9 H); 13C NMR (100 MHz, CDCl3)
δ 21.9, 123.5, 124.5, 128.50, 128.55, 128.9, 130.3, 134.8, 136.0,
139.9, 148.0, 192.2; mass spectrum (EI) m/z 254 (M+, 13); HRMS
calcd for C16H14OS 254.0765, found 254.0771. 4g: white solid; 1H
NMR (400 MHz, CDCl3) δ 2.38 (s, 3 H), 6.78 (d, J ) 16.0 Hz, 1
H), 7.24 (d, J ) 7.6 Hz, 2 H), 7.36-7.40 (m, 5 H), 7.53-7.55 (m,
2 H), 7.66 (d, J ) 16.0 Hz, 1 H); 13C NMR (100 MHz, CDCl3) δ
21.5, 123.9, 124.0, 128.3, 128.8, 129.8, 130.5, 133.8, 134.3, 139.5,
141.1, 188.0; mass spectrum (EI) m/z 254 (M+, 1); HRMS calcd
Experimental Section
General Comments. The 31P and1H NMR spectra were recorded
with a JEOL JMN Alice-400 spectrometer (160 and 400 MHz,
respectively) in C6D6, CD2Cl2, or toluene-d8 solution. The chemical
shifts of the 31P NMR spectra were recorded relative to 85% H3-
PO4(aq) as an external standard, and SdP(C6H4OMe-p)3 was used
as an internal standard to calculate the yields of products. The
1
1
for C16H14OS 254.0765, found 254.0759. 4h: yellow solid; H
chemical shifts in the H NMR spectra were recorded relative to
NMR (400 MHz, CDCl3) δ 2.03 (s, 3 H), 5.80 (s, 1 H), 6.25 (s, 1
H), 7.64 (d, J ) 8.7 Hz, 2 H), 8.27 (d, J ) 8.7 Hz, 2 H); 13C NMR
(100 MHz, CDCl3) δ 18.1, 123.5, 124.7, 134.9, 136.0, 142.8, 147.8,
188.7; mass spectrum (EI) m/z 223 (M+, 1); HRMS calcd for C10H9-
C6H6 (δ 7.15), CH2Cl2 (δ 5.32), or toluene (δ 2.09). IR spectra
were recorded with a Perkin-Elmer FT-IR (Model 1600) spectrom-
eter. The X-ray crystal data of anti-7g were collected by a Rigaku
RAXIS-RAPID imaging plate diffractometer, and the ORTEP
drawing are shown in the Supporting Information with 50%
probability ellipsoids. Elemental analyses were performed in the
Instrumental Analysis Center of the Faculty of Engineering, Osaka
University. Acid chlorides 1a and 1b were commercially obtained.
Thioester 4a was prepared from the dehydrochlorination of S-(p-
tolyl)-3-(chloro)propanethioate using triethylamine (J. Am. Chem.
Soc. 1969, 91, 913). Thioesters 4d-f were synthesized according
to the literature (Tetrahedron Lett. 2001, 42, 1567). Other thioesters
(4b,c, 4g, and 4h-l) were prepared from the reactions of the
corresponding acid chlorides with thiols in the presence of pyridine.
The platinum complex Pt(PPh3)2(C2H4) (2) was synthesized ac-
cording to the literature (Inorg. Synth. 1978, 18, 120). C6D6, toluene-
d8, and C6H6 were purified by distillation from sodium benzophe-
none ketyl before use. CD2Cl2 was distilled from CaH2. The
structures of 5, trans-6, and 7 were determined by comparing their
1
NO3S 223.0303, found 223.0308. 4i: orange solid; H NMR (400
MHz, CDCl3) δ 1.97 (d, J ) 6.8 Hz, 3 H), 6.23 (d, J ) 15.2 Hz,
1 H), 7.06 (dt, J ) 6.8 Hz, J ) 14.8 Hz, 1 H), 7.63 (d, J ) 8.2 Hz,
2 H), 8.25 (d, J ) 8.2 Hz, 2 H); 13C NMR (100 MHz, CDCl3) δ
18.4, 123.7, 128.8, 134.6, 136.2, 143.6, 147.8, 185.1; mass spectrum
(EI) m/z 223 (M+, 0.4); HRMS calcd for C10H9NO3S 223.0303,
1
found 223.0305. 4j: yellow oil; H NMR (400 MHz, CDCl3) δ
1.13 (d, J ) 6.8 Hz, 6 H), 2.86 (sept, J ) 6.8 Hz, 1 H), 5.75 (s, 1
H), 6.23 (s, 1 H), 7.63 (d, J ) 8.8 Hz, 2 H), 8.26 (d, J ) 8.8 Hz,
2 H); 13C NMR (100 MHz, CDCl3) δ 21.7, 30.2, 121.4, 123.7,
135.0, 136.5, 147.9, 154.2, 189.6; mass spectrum (EI) m/z 251 (M+,
0.2); HRMS calcd for C12H13NO3S 251.0616, found 251.0607. 4k:
yellow solid; 1H NMR (400 MHz, CDCl3) δ 5.95 (s, 1 H), 6.35 (s,
1 H), 7.39-7.45 (m, 5 H), 7.65 (d, J ) 9.0 Hz, 2 H), 8.26 (d, J )
9.0 Hz, 2 H); 13C NMR (100 MHz, CDCl3) δ 123.8, 124.4, 128.2,
128.3, 128.9, 134.8, 135.0, 136.4, 147.3, 148.0, 189.0; mass
spectrum (EI) m/z 285 (M+, 9.4); HRMS calcd for C15H11NO3S
31P NMR chemical shifts and coupling constants (JP-P and JPt-P
with those of the authentic samples 5a, trans-6l, and 7g.
)
Spectral Data of 4. 4a: colorless oil; 1H NMR (400 MHz,
CDCl3) δ 2.36 (s, 3 H), 5.71 (dd, J ) 1.6 Hz, J ) 9.6 Hz, 1 H),
6.35 (dd, J ) 1.6 Hz, 17.2 Hz, 1 H), 6.42 (dd, J ) 9.6 Hz, J )
17.2 Hz, 1 H), 7.21 (d, J ) 8.2 Hz, 2 H), 7.31 (d, J ) 8.2 Hz, 2
H); 13C NMR (100 MHz, CDCl3) δ 21.4, 123.4, 126.9, 129.8, 134.1,
134.2, 139.4, 188.4; mass spectrum (EI) m/z 178 (M+, 40); HRMS
calcd for C10H10OS 178.0452, found 178.0444. 4b: yellow oil; 1H
1
285.0460, found 285.0547. 4l: yellow solid; H NMR (400 MHz,
CDCl3) δ 6.78 (d, J ) 15.8 Hz, 1 H), 7.42-7.44 (m, 3 H), 7.57-
7.59 (m, 2 H), 7.68 (d, J ) 8.6 Hz, 2 H), 7.72 (d, J ) 15.8 Hz, 1
H), 8.27 (d, J ) 8.6 Hz, 2 H); 13C NMR (100 MHz, CDCl3) δ
123.4, 123.7, 128.5, 128.9, 131.1, 133.4, 134.6, 136.2, 142.7, 147.9,
185.2; mass spectrum (CI) m/z 286 ([M - H]+, 100); HRMS calcd
for C15H12NO3S (M - H) 286.0538, found 286.0533.
Preparation of Authentic 5a. Into a dry two-necked reaction
vessel equipped with a stirring bar were added 2 (703.0 mg, 0.94
mmol), 4a (174.9 mg, 0.98 mmol), and C6H6 (3 mL). After the
reaction mixture was stirred at 25 °C for 30 min, hexane (ca. 50
(14) (a) Kurosawa, H.; Kajimaru, H.; Ogoshi, S.; Yoneda, H.; Miki, K.;
Kasai, N.; Murai, S.; Ikeda, I. J. Am. Chem. Soc. 1992, 114, 8417, and
references therein. (b) Osakada, K.; Chiba, T.; Nakamura, Y.; Yamamoto,
T.; Yamamoto, A. J. Chem. Soc., Chem. Commun. 1986, 1589.

2954 Organometallics, Vol. 25, No. 12, 2006
Minami et al.
mL) was added into the mixture and the precipitate was collected
by filtration. Then the solid was washed by hexane (10 mL × 3)
and dried to give 5a (672.0 mg, 80%). 5a: mp 130 °C (a white
solid); 1H NMR (400 MHz, C6D6) δ 2.01 (s, 3 H), 2.53-2.60 (m,
1 H), 3.00-3.07 (m, 1 H), 3.90-4.06 (m, 1 H), 6.84-6.97 (m, 20
H), 7.18-7.20 (m, 2 H), 7.43-7.56 (m, 12 H); 31P NMR (160 Hz,
(d, JP-P ) 16 Hz, JPt-P ) 1349 Hz). trans-3b: 31P NMR (160
MHz, toluene-d8) δ 21.0 (s, JPt-P ) 3378 Hz).
Reaction of R,â-Unsaturated Thioester 4 with 2. General
Procedure (Table 1). Into a dry Pyrex NMR tube were added 2
(0.020 mmol), 4 (0.022 mmol), SdP(C6H4OMe-p)3 (0.01 mmol),
and solvent (0.5 mL) under a N2 atmosphere. The reaction was
1
roughly monitored by 31P and H NMR spectroscopy at 25 °C to
C6D6) δ 29.5 (d, JP-P ) 38 Hz, JPt-P ) 4038 Hz), 31.4 (d, JP-P
)
38 Hz, JPt-P ) 3567 Hz); IR (KBr) 3050, 1652, 1478, 1433, 1360,
1155, 1095, 967, 943, 808, 742, 692, 540, 517, 510 cm-1. Anal.
Calcd for C46H40OP2PtS: C, 61.53; H, 4.49. Found: C, 61.48; H,
4.49.
determine the time required for reaching the equilibrium state among
5, 6, and 7. Then the reaction was again continuously monitored
by using an automatic measuring system until the equilibrium of
the system was well-achieved.
Reaction of 4a with 2 in C6D6 (run 1). The reaction was
Preparation of Authentic trans-6l. Into a dry two-necked
reaction vessel equipped with a stirring bar were added 2 (747.0
mg, 1.0 mmol), 4l (301.5 mg, 1.1 mmol), and C6H6 (5 mL). After
the reaction mixture was stirred at 25 °C for 1.5 h, 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 methanol (10 mL × 3) and then dried to give trans-6l (849.8
mg, 85%). trans-6l: mp 142 °C (orange solid); 1H NMR (400 MHz,
C6D6) δ 6.08 (d, J ) 16.0 Hz, 1 H), 6.82-7.15 (m, 27 H), 7.47 (d,
J ) 16.0 Hz, 1 H), 7.57 (d, J ) 9.2 Hz, 2 H), 7.80-7.83 (m, 10
H); 31P NMR (160 Hz, C6D6) δ 16.0 (s, JPt-P ) 3228 Hz); IR (KBr)
3056, 1580, 1566, 1493, 1482, 1435, 1319, 1094, 742, 692, 523,
514 cm-1. Anal. Calcd for C51H41NO3P2PtS: C, 60.95; H, 4.11;
N, 1.39. Found: C, 60.69; H, 4.03; N, 1.43.
1
continuously monitored by 31P and H NMR spectroscopy using
an automatic measurement program system for 3 h. The 31P NMR
spectrum showed the formation of 5a and syn-7a. The reaction time
and the yields of 5a and syn-7a at the time are as follows: 20 min,
100%, 0%; 2 h, 100%, 0%; 140 min, 99.7%, 0.3%; 3h, 99.5%,
0.5%. 5a: 31P NMR (160 MHz, C6D6) δ 29.5 (d, JP-P ) 38 Hz,
JPt-P ) 4038 Hz), 31.4 (d, JP-P ) 38 Hz, JPt-P ) 3567 Hz). syn-
7a: 31P NMR (160 MHz, C6D6) δ 15.0 (s, JPt-P ) 4171 Hz).
Reaction of 4a with 2 in CD2Cl2 (run 2). An automatic NMR
measurement program system has been used to continuously
monitor the reaction for 3 h. The 31P NMR spectrum showed the
formation of 5a, trans-6a, and syn-7a. The reaction time and the
yields of 5a, trans-6a, and syn-7a at the time are as follows: 20
min, 99.7%, 0.3%, 0%; 2 h, 99.4%, 0.3%, 0.3%; 140 min, 98.9%,
0.4%, 0.7%; 3 h, 98.9%, 0.4%, 0.7%. 5a: 31P NMR (160 MHz,
CD2Cl2) δ 28.9 (d, JP-P ) 37 Hz, JPt-P ) 4060 Hz), 30.7 (d, JP-P
) 37 Hz, JPt-P ) 3541 Hz). trans-6a: 31P NMR (160 MHz, CD2-
Cl2) δ 17.6 (s, JPt-P ) 3272 Hz). syn-7a: 31P NMR (160 MHz,
CD2Cl2) δ 15.0 (s, JPt-P ) 4110 Hz).
Preparation of Authentic 7g. Into a dry two-necked reaction
vessel equipped with a stirring bar were added 2 (897.0 mg, 1.2
mmol), 4g (321.2 mg, 1.3 mmol), and C6H6 (5 mL). After the
reaction mixture was stirred at 25 °C for 2 h, 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 methanol (10 mL × 3) and then dried to give 7g (394.9 mg,
46%, syn/anti ) 61/39). A suitable crystal of anti-7g for X-ray
crystallographic analysis was prepared by recrystallization from
CH2Cl2/pentane at 25 °C. 7g (the following data were collected
Reaction of 4b with 2 in C6D6 (run 3). An automatic NMR
measurement program system was used to continuously monitor
the reaction for 7 h. The 31P NMR spectrum showed the formation
of 5b, 6b, and 7b. The reaction time, the yields of 5b, 6b (cis/
trans), and 7b (syn/anti), and the ratios of 5b/6b and 6b/7b at the
time are as follows: 20 min, 78%, 4.4% (9/91), 17% (47/53), 95/
5, 21/79; 40 min, 64%, 7.3% (4/96), 28% (68/32), 90/10, 21/79; 1
h, 48%, 10% (10/90), 42% (76/24), 83/17, 19/81; 2 h, 24.0%, 11.6%
(5/95), 64.0% (80/20), 67/33, 15/85; 3 h, 16.0%, 11.7% (6/94),
70.0% (80/20), 58/42, 16/84; 4 h, 12.0%, 11.7% (6/94), 76.0% (79/
21), 51/49, 13/87; 5 h, 12.0%, 11.5% (4/96), 76.0% (80/20), 51/
49, 13/87; 6 h, 11.0%, 11.6% (5/95), 77.0% (81/19), 49/51, 13/87;
7 h, 12.0%, 11.8% (7/93), 76.0% (80/20), 50/50, 13/87. Although
the ratio of 5b/6b after 3 h (58/42) was different from that after 4
h (51/49), those after 4 and 7 h were virtually the same. This is
why it was concluded that equilibrium between 5b/6b was attained
in a range of time of 3-4 h (51/49). The changes of yields between
5b and 6b from the early stage of this reaction indicated 6b was
produced from 5b. The equilibrium between 6b/7b was also attained
in a range of time of 3-4 h (13/87). 5b: 31P NMR (160 MHz,
1
from a mixture of stereoisomers): mp 186 °C (yellow solid); H
NMR (160 MHz, C6D6) (syn isomer) δ 1.65 (s, 3 H), 2.11 (s, 3 H),
6.13 (d, J ) 16.0 Hz, 1 H), 6.50 (d, J ) 7.6 Hz, 2 H), 6.58 (d, J
) 8.0 Hz, 2 H), 7.51 (d, J ) 8.0 Hz, 2 H), 7.58 (d, J ) 7.6 Hz, 2
H); (anti isomer) δ 1.88 (s, 6 H), 6.14 (d, J ) 16.0 Hz, 1 H) (other
peaks overlapped in the region of δ 6.83-7.15 and 7.69-7.85 were
not able to be read distinctively); 31P NMR (160 Hz, C6D6) (syn
isomer) δ 15.0 (s, JPt-P ) 4164 Hz); (anti isomer) δ 16.8 (s, JPt-P
) 4028 Hz); IR (KBr) 3055, 1626, 1582, 1486, 1434, 1096, 758,
693, 535, 511, 498 cm-1. Anal. Calcd for C68H58O2P2Pt2S2: C,
57.38; H, 4.11. Found: C, 57.66; H, 4.03.
Reaction of 1a with 2 (eq 1). Into a dry Pyrex NMR tube were
added 2 (15.5 mg, 0.021 mmol), 1a (4.0 mg, 0.044 mmol), and
SdP(C6H4OMe-p)3 (1.7 mg, 0.0044 mmol). Then ca. 0.5 mL of
toluene-d8 was transferred by the freeze-pump-thaw method. The
31P NMR spectrum taken after 10 min at -50 °C showed the
quantitative formation of acylplatinum complex 3a (cis/trans ) 57/
43), which completely isomerized to the trans isomer at 10 °C after
10 min. No formation of π-complex Pt[(Cl)C(O)C(H)dCH2](PPh3)2
was observed during the course of the reaction. cis-3a: 31P NMR
(160 MHz, toluene-d8) δ 15.9 (d, JP-P ) 17 Hz, JPt-P ) 4662 Hz),
18.2 (d, JP-P ) 17 Hz, JPt-P ) 1378 Hz). trans-3a: 31P NMR (160
MHz, toluene-d8) δ 22.2 (s, JPt-P ) 3312 Hz).
C6D6) δ 28.0 (d, JP-P ) 41 Hz, JPt-P ) 3827 Hz), 31.0 (d, JP-P
)
41 Hz, JPt-P ) 3724 Hz). cis-6b: 31P NMR (160 MHz, C6D6) δ
16.7 (d, JP-P ) 19 Hz, the value of JPt-P was not readable because
of low intensity), 18.4 (d, JP-P ) 19 Hz, the value of JPt-P was not
readable because of low intensity). trans-6b: 31P NMR (160 MHz,
C6D6) δ 16.4 (s, JPt-P ) 3291 Hz). syn-7b: 31P NMR (160 MHz,
C6D6) δ 14.6 (s, JPt-P ) 4188 Hz). anti-7b: 31P NMR (160 MHz,
C6D6) δ 16.2 (s, JPt-P ) 4124 Hz).
Reaction of 1b with 2 (eq 1). The reaction of 1b with 2 was
carried out in a manner similar to the reaction of 1b with 2. The
31P NMR spectrum taken after 10 min at -50 °C showed the
quantitative formation of 3b (cis/trans ) 96/4), which completely
isomerized to the trans isomer at 10 °C after 10 min. No formation
of π-complex Pt[(Cl)C(O)C(H)dC(Ph)(H)-(E)](PPh3)2 was ob-
served during the course of the reaction. cis-3b: 31P NMR (160
MHz, toluene-d8) δ 15.4 (d, JP-P ) 16 Hz, JPt-P ) 4715 Hz), 17.4
Reaction of 4b with 2 in CD2Cl2 (run 4). An automatic NMR
measurement program system has been used to continuously
monitor the reaction for 8 h. The 31P NMR spectrum showed the
formation of 5b, 6b, and 7b. The reaction time, the yields of 5b,
6b (cis/trans) and 7b (syn/anti), and the ratios of 5b/6b and 6b/7b
at the time are as follows: 20 min, 66%, 20% (45/55), 14% (51/
49), 77/23, 59/41; 40 min, 45%, 24% (24/76), 31% (69/31), 65/35,
44/56; 1 h, 33%, 26% (19/81), 41% (73/27), 56/44, 39/61; 2 h,

Reactions of R,â-Unsaturated Thioesters with Pt(0)
Organometallics, Vol. 25, No. 12, 2006 2955
15%, 25% (17/83), 59% (79/21), 38/62, 30/70; 3 h, 10%, 24% (15/
85), 66% (81/19), 29/71, 27/73; 4 h, 9%, 22% (12/88), 69% (82/
18), 29/71, 24/76; 5 h, 7%, 21% (14/86), 72% (82/18), 25/75, 23/
77; 6 h, 6%, 21% (13/87), 73% (83/17), 22/78, 22/78; 7 h, 6%,
20% (15/85), 73% (82/18), 23/77, 22/78; 8 h, 6%, 20% (14/86),
74% (82/18), 23/77, 21/79. Although the ratio of 5b/6b after 5 h
(25/75) was different from that after 6 h (22/78), those after 6 and
8 h were virtually the same. This is why it was concluded that
equilibrium between 5b/6b was attained in a range of time of 5-6
h (22/78). The changes of yields between 5b and 6b from the early
stage of this reaction indicated 6b was produced from 5b. The
equilibrium between 6b/7b was also attained in a range of time of
5-6 h (22/78). 5b: 31P NMR (160 MHz, CD2Cl2) δ 27.5 (d, JP-P
) 40 Hz, JPt-P ) 3836 Hz), 30.5 (d, JP-P ) 40 Hz, JPt-P ) 3705
Hz). cis-6b: 31P NMR (160 MHz, CD2Cl2) δ 15.7 (d, JP-P ) 19
Hz, the value of JPt-P was not readable because of low intensity),
17.5 (d, JP-P ) 19 Hz, the value of JPt-P was not readable because
of low intensity). trans-6b: 31P NMR (160 MHz, CD2Cl2) δ 17.1
(s, JPt-P ) 3205 Hz). syn-7b: 31P NMR (160 MHz, CD2Cl2) δ
14.5 (s, JPt-P ) 4138 Hz). anti-7b: 31P NMR (160 MHz, CD2Cl2)
δ 16.1 (s, JPt-P ) 4019 Hz).
Reaction of 4c with 2 in C6D6 (run 5). The 31P NMR spectrum
showed the formation of 5c, trans-6c, and 7c. The reaction time,
the yields of 5c, trans-6c, and 7c (syn/anti), and the ratios of 5c/
trans-6c and trans-6c/7c at the time are as follows: 20 min, 11%,
7%, 82% (63/37), 61/39, 8/92; 40 min, 8%, 6%, 86% (64/36), 57/
43, 7/93; 1 h, 8%, 6%, 86% (63/37), 57/43, 7/93. Although the
ratio of 5c/trans-6c after 20 min (61/39) was different from that
after 40 min (57/43), those after 40 min and 1 h were virtually the
same. This is why it was concluded that equilibrium between 5c/
trans-6c was attained within 40 min (57/43). The equilibrium
between trans-6c/7c was also attained within 40 min (7/93). 5c:
31P NMR (160 MHz, C6D6) δ 29.6 (d, JP-P ) 44 Hz, JPt-P ) 4210
Hz), 30.7 (d, JP-P ) 44 Hz, JPt-P ) 3376 Hz). trans-6c: 31P NMR
(160 MHz, C6D6) δ 17.1 (s, JPt-P ) 3310 Hz). syn-7c: 31P NMR
(160 MHz, C6D6) δ 15.3 (s, JPt-P ) 4208 Hz). anti-7c: 31P NMR
(160 MHz, C6D6) δ 17.1 (s, JPt-P ) 4083 Hz).
Reaction of 4c with 2 in CD2Cl2 (run 6). An automatic NMR
measurement program system has been used to continuously
monitor the reaction for 1 h. The 31P NMR spectrum showed the
formation of 5c, trans-6c, and 7c. The reaction time, the yields of
5c, trans-6c, and 7c (syn/anti), and the ratios of 5c/trans-6c and
trans-6c/7c at the time are as follows: 20 min, 6%, 22%, 72%
(75/25), 21/79, 23/77; 40 min, 4%, 19%, 77% (74/26), 17/83, 20/
80; 1 h, 4%, 18%, 78% (74/26), 18/82, 19/81. Although the ratio
of 5c/trans-6c after 20 min (21/79) was different from that after
40 min (17/83), those after 40 min and 1 h were virtually the same.
This is why it was concluded that equilibrium between 5c/trans-
6c was attained within 40 min (17/83). The equilibrium between
trans-6c/7c was also attained within 40 min (20/80). 5c: 31P NMR
(160 MHz, CD2Cl2) δ 29.0 (d, JP-P ) 43 Hz, the value of JPt-P
was not readable because of low intensity), 30.1 (d, JP-P ) 43 Hz,
the value of JPt-P was not readable because of low intensity). trans-
6c: 31P NMR (160 MHz, CD2Cl2) δ 17.8 (s, JPt-P ) 3313 Hz).
syn-7c: 31P NMR (160 MHz, CD2Cl2) δ 15.4 (s, JPt-P ) 4158 Hz).
anti-7c: 31P NMR (160 MHz, CD2Cl2) δ 17.4 (s, JPt-P ) 4027
Hz).
7/93; 9 h, 22%, 5%, 72% (75/25), 81/19, 6/94; 10 h, 21%, 6%,
73% (76/24), 78/22, 8/92; 13 h, 18%, 5%, 77% (73/27), 78/22,
6/94. Although the ratio of 5d/trans-6d after 9 h (81/19) was
different from that after 10 h (78/22), those after 10 and 13 h were
virtually the same. This is why it was concluded that equilibrium
between 5d/trans-6d was attained in a range of time of 9-10 h
(78/22). These data also demonstrated that 6d was produced from
5d. On the other hand, equilibrium between trans-6d/7d was
attained in a range of time of 3-6 h (7/93). 5d: 31P NMR (160
MHz, C6D6) δ 27.5 (d, JP-P ) 40 Hz, JPt-P ) 3863 Hz), 30.5 (d,
JP-P ) 40 Hz, JPt-P ) 3669 Hz). trans-6d: 31P NMR (160 MHz,
C6D6) δ 16.2 (s, JPt-P ) 3312 Hz). syn-7d: 31P NMR (160 MHz,
C6D6) δ 14.6 (s, JPt-P ) 4177 Hz). anti-7d: 31P NMR (160 MHz,
C6D6) δ 16.3 (s, JPt-P ) 4124 Hz).
Reaction of 4e with 2 in C6D6 (run 8). An automatic
measurement program system has been used to continuously
monitor the reaction for 71 h. The 31P NMR spectrum showed the
formation of 5e, trans-6e, and 7e. The reaction time, the yields of
5e, trans-6e, and 7e (syn/anti), and the ratios of 5e/trans-6e and
trans-6e/7e at the time are as follows: 20 min, 99.5%, 0.5%, 0%,
99.5/0.5, 100/0; 40 min, 98.3%, 0.7%, 0.9% (100/0), 99/1, 44/56;
1 h, 96.6%, 0.7%, 2.7% (82/18), 99/1, 21/79; 6 h, 79%, 2%, 19%
(80/20), 98/2, 10/90; 10 h, 65%, 3%, 32% (81/19), 96/4, 9/91; 15
h, 53%, 3%, 44% (81/19), 95/5, 6/94; 21 h, 43%, 4%, 53% (80/
20), 91/9, 7/93; 25 h, 37%, 4%, 59% (81/19), 90/10, 6/94; 30 h,
32%, 4%, 64% (82/18), 89/11, 6/94; 35 h, 30%, 4%, 66% (81/19),
88/12, 6/94; 40 h, 27%, 4%, 69% (80/20), 87/13, 5/95; 47 h, 25%,
5%, 70% (82/18), 83/17, 7/93; 52 h, 23%, 5%, 72% (81/19), 82/
18, 6/94; 55 h, 22%, 5%, 73% (81/19), 81/19, 6/94; 66 h, 21%,
5%, 74% (80/20), 81/19, 6/94; 71 h, 21%, 5%, 74% (81/19), 81/
19, 6/94. Although the ratio of 5e/trans-6e after 52 h (82/18) was
different from that after 55 h (81/19), those after 55 and 71 h were
virtually the same. This is why it was concluded that equilibrium
between 5e/trans-6e was attained in a range of time of 52-55 h
(81/19). These data also demonstrated that 6e was produced from
3e. On the other hand, the equilibrium between trans-4e/5e was
attained in a range of time of 10-15 h (6/94). 5e: 31P NMR (160
MHz, C6D6) δ 26.8 (d, JP-P ) 37 Hz, JPt-P ) 3867 Hz), 30.2 (d,
JP-P ) 37 Hz, JPt-P ) 3732 Hz). trans-6e: 31P NMR (160 MHz,
C6D6) δ 15.8 (s, JPt-P ) 3299 Hz). syn-7e: 31P NMR (160 MHz,
C6D6) δ 14.4 (s, JPt-P ) 4208 Hz). anti-7e: 31P NMR (160 MHz,
C6D6) δ 16.3 (s, JPt-P ) 4114 Hz).
Reaction of 4f with 2 in C6D6 (run 9). An automatic measure-
ment program system has been used to continuously monitor the
reaction for 20 h. The 31P NMR spectrum showed the formation of
5f, trans-6f, and 7f. The reaction time, the yields of 5f, trans-6f,
and 7f (syn/anti), and the ratios of 5f/trans-6f and trans-6f/7f at
the time are as follows: 20 min, 98%, 2%, 0%, 98/2, 100/0; 40
min, 91%, 4%, 5% (60/40), 96/4, 44/56; 1 h, 86%, 5%, 9% (67/
33), 95/5, 36/64; 3 h, 69%, 6%, 24% (75/25), 92/8, 20/80; 6 h,
50%, 8%, 41% (78/22), 86/14, 16/84; 7 h, 32%, 8%, 60% (78/22),
80/20, 12/88; 8 h, 29%, 8%, 63% (78/22), 78/22, 11/89; 9 h, 27%,
8%, 65% (78/22), 77/23, 11/89; 10 h, 26%, 7%, 67% (76/24), 79/
21, 9/91; 11 h, 24%, 7%, 69% (76/24), 77/23, 9/91; 12 h, 21%,
7%, 72% (76/24), 75/25, 9/91; 13 h, 20%, 7%, 73% (76/24), 74/
26, 9/91; 14 h, 18%, 7%, 75% (76/24), 72/28, 9/91; 15 h, 17%,
7%, 76% (76/24), 71/29, 8/92; 20 h, 14%, 6%, 80% (77/23), 70/
30, 7/93. Although the ratio of 5f/trans-6f after 14 h (72/28) was
different from that after 15 h (71/29), those after 15 and 20 h were
virtually the same. This is why it was concluded that equilibrium
between 5f/trans-6f was attained in a range of time of 14-15h
(71/29). The changes of yields between 5f and 6f from the early
stage of this reaction indicated 6f was produced from 5f. On the
other hand, the equilibrium between trans-6f/7f was attained in a
range of time of 9-10 h (9/91). 5f: 31P NMR (160 MHz, C6D6) δ
26.6 (d, JP-P ) 40 Hz, JPt-P ) 4013 Hz), 30.1 (d, JP-P ) 40 Hz,
JPt-P ) 3696 Hz). trans-6f: 31P NMR (160 MHz, C6D6) δ 16.1 (s,
Reaction of 4d with 2 in C6D6 (run 7). An automatic
measurement program system has been used to continuously
monitor the reaction for 13 h. The 31P NMR spectrum showed the
formation of 5d, trans-6d, and 7d. The reaction time, the yields of
5d, trans-6d, and 7d (syn/anti), and the ratios of 5d/trans-6d and
trans-6d/7d at the time are as follows: 20 min, 95%, 2%, 2% (100/
0), 98/2, 50/50; 40 min, 87%, 2%, 11% (66/34), 98/2, 15/85; 1 h,
79%, 2%, 19% (65/35), 98/2, 10/90; 3 h, 53%, 4%, 43% (70/30),
93/7, 9/91; 6 h, 32%, 5%, 63% (74/26), 86/14, 7/93; 7 h, 28%,
5%, 67% (74/26), 85/15, 7/93; 8 h, 24%, 5%, 71% (74/26), 83/17,

2956 Organometallics, Vol. 25, No. 12, 2006
Minami et al.
JPt-P ) 3259 Hz). syn-7f: 31P NMR (160 MHz, C6D6) δ 14.6 (s,
JPt-P ) 4141 Hz). anti-7f: 31P NMR (160 MHz, C6D6) δ 16.4 (s,
JPt-P ) 4081 Hz).
between trans-6g/7g was also attained within 40 min (8/92) 5g:
31P NMR (160 MHz, C6D6) δ 27.1 (d, JP-P ) 38 Hz, JPt-P ) 4134
Hz), 27.8 (d, JP-P ) 38 Hz, JPt-P ) 3591 Hz). trans-6g: 31P NMR
(160 MHz, C6D6) δ 16.8 (s, JPt-P ) 3281 Hz). syn-7g: 31P NMR
(160 MHz, C6D6) δ 15.0 (s, JPt-P ) 4171 Hz). anti-7g: 31P NMR
(160 MHz, C6D6) δ 16.8 (s, JPt-P ) 4022 Hz).
Reaction of 4g with 2 Using 4.8 Equiv of 4g in C6D6 (run
13). An automatic NMR measurement program system has been
used to continuously monitor the reaction for 1 h. The 31P NMR
spectrum showed the formation of 5g, trans-6g, and 7g. The reaction
time, the yields of 5g, trans-6g, and 7g (syn/anti), and the ratios of
5g/trans-6g and trans-6g/7g at the time are as follows: 20 min,
46%, 5%, 48% (60/40), 90/10, 9/91; 40 min, 39%, 4%, 56% (63/
37), 91/9, 7/93; 1 h, 36%, 4%, 56% (63/37), 90/10, 7/93. The
equilibria between 5g and trans-6g, and trans-6g and 7g were
attained within 40 min (91/9 and 7/93). When this result was
compared with that of run 12 of Table 1, it was obvious that the
time required for reaching the equilibrium was not affected by the
excess amount of 4g.
Reaction of 4f with 2 Using 4.3 Equiv of 4f in C6D6 (run 10).
An automatic NMR measurement program system has been used
to continuously monitor the reaction for 20 h. The 31P NMR
spectrum showed the formation of 5f, trans-6f, and 7f. The reaction
time, the yields of 5f, trans-6f, and 7f (syn/anti), and the ratios of
5f/trans-6f and trans-6f/7f at the time are as follows: 20 min, 98%,
2%, 0%, 98/2, 100/0; 40 min, 89%, 4%, 7% (73/27), 96/4, 36/64;
1 h, 82%, 6%, 12% (71/29), 93/7, 33/67; 3 h, 57%, 8%, 35% (77/
23), 88/12, 19/81; 6 h, 35%, 8%, 56% (77/23), 81/19, 13/87; 7 h,
32%, 8%, 59% (78/22), 80/20, 12/88; 8 h, 28%, 7%, 65% (74/26),
80/20, 10/90; 9 h, 25%, 8%, 67% (77/23), 76/24, 11/89; 10 h, 23%,
8%, 69% (76/24), 74/26, 10/90; 11 h, 21%, 8%, 71% (77/23), 72/
28, 10/90; 12 h, 21%, 7%, 72% (76/24), 75/25, 9/91; 13 h, 19%,
8%, 73% (78/22), 70/30, 10/90; 14 h, 18%, 8%, 74% (76/24), 69/
31, 10/90; 15 h, 17%, 8%, 75% (78/22), 68/32, 10/90; 20 h, 15%,
7%, 78% (76/24), 68/32, 8/92. The equilibrium between 5f and
trans-6f was attained in a range of time of 14-15 h (68/32). On
the other hand, the equilibrium between trans-6f and 7f was attained
in a range of time of 7-8 h (10/90). When this result was compared
with that of run 9 of Table 1, it was obvious that the time required
for reaching the equilibrium was not affected by the excess amount
of 4f.
Reaction of 4g with 2 in CD2Cl2 (run 14). An automatic NMR
measurement program system has been used to continuously
monitor the reaction for 3 h. The 31P NMR spectrum showed the
formation of 5g, trans-6g, and 7g. The reaction time, the yields of
5g, trans-6g, and 7g (syn/anti), and the ratios of 5g/trans-6g and
trans-6g/7g at the time are as follows: 20 min, 38%, 16%, 45%
(71/29), 70/30, 26/74; 40 min, 32%, 14%, 53% (72/28), 70/30, 21/
79; 60 min, 28%, 13%, 59% (71/29), 68/32, 18/82; 80 min, 26%,
11%, 63% (70/30), 70/30, 15/85; 100 min, 24%, 11%, 65% (71/
29), 69/31, 14/86; 2 h, 22%, 11%, 67% (70/30), 67/33, 14/86; 140
min, 24%, 11%, 65% (72/28), 69/31, 14/86; 160 min, 24%, 11%,
65% (72/28), 69/31, 14/86; 3 h, 23%, 10%, 67% (69/31), 69/31,
13/87. The ratio of 5g/trans-6g after 40 min (70/30) and 3 h (69/
31) were virtually the same. This is why it was concluded that
equilibrium between 5g and trans-6g was attained within 40 min
(70/30). On the other hand, the equilibrium between trans-6g and
7g was attained in a range of time of 60-80 min (15/85). 5g: 31P
NMR (160 MHz, CD2Cl2) δ 26.6 (d, JP-P ) 37 Hz, JPt-P ) 4168
Hz), 27.1 (d, JP-P ) 37 Hz, JPt-P ) 3572 Hz). trans-6g: 31P NMR
(160 MHz, CD2Cl2) δ 17.6 (s, JPt-P ) 3280 Hz). syn-7g: 31P NMR
(160 MHz, CD2Cl2) δ 15.3 (s, JPt-P ) 4133 Hz). anti-5g: 31P NMR
(160 MHz, CD2Cl2) δ 17.4 (s, JPt-P ) 3977 Hz).
Reaction of 7g with 2.0 Equiv of PPh3 in C6D6. Into a dry
Pyrex NMR tube were added 7g (syn/anti ) 61/39, 14.2 mg, 0.010
mmol), PPh3 (5.2 mg, 0.020 mmol), SdP(C6H4OMe-p)3 (3.1 mg,
0.0080 mmol), and C6D6 (0.5 mL) under N2 atmosphere. Then the
reaction was monitored by 31P and 1H NMR spectra at 25 °C. The
31P NMR spectrum showed the formation of 5g, trans-6g, and 7g.
The reaction time, the yields of 5g, trans-6g, and 7g (syn/anti),
and the ratios of 5g/trans-6g and trans-6g/7g at the time are as
follows: 20 min, 8.0%, 0.9%, 51.0% (67/33), 90/10, 2/98; 40 min,
15%, 2%, 44% (66/34), 88/12, 4/96; 1 h, 22%, 2%, 47% (64/36),
92/8, 4/96; 3 h, 34%, 5%, 47% (66/34), 87/13, 10/90; 6 h, 35%,
5%, 47% (66/34), 88/12, 10/90. The ratios of 5g/trans-6g and trans-
6g/7g eventually reached 88/12 and 10/90, respectively, and were
virtually the same as that of run 12 of Table 1. These results verified
the equilibrium among 5g, trans-6g, and 7g.
Reaction of 4f with 2 in CD2Cl2 (run 11). An automatic
measurement program system has been used to continuously
monitor the reaction for 20 h. The 31P NMR spectrum showed the
formation of 5f, 6f, and 7f. The reaction time, the yields of 5f, 6f
(cis/trans), and 7f (syn/anti), and the ratios of 5f/6f and 6f/7f at
the time are as follows: 20 min, 92%, 6% (17/83), 1.5% (60/40),
94/6, 80/20; 40 min, 88%, 9% (22/78), 2.9% (69/31), 91/9, 76/24;
1 h, 85%, 11% (19/81), 4% (68/32), 89/11, 71/29; 3 h, 55%, 19%
(22/78), 26% (75/25), 75/25, 42/58; 6 h, 33%, 19% (17/83), 48%
(82/18), 64/36, 28/72; 10 h, 24%, 17% (20/80), 59% (85/15), 58/
42, 22/78; 11 h, 22%, 17% (20/80), 61% (85/15), 56/44, 21/79; 12
h, 20%, 16% (21/79), 64% (86/14), 55/45, 20/80; 13 h, 19%, 15%
(20/80), 66% (86/14), 55/45, 19/81; 14 h, 18%, 15% (19/81), 67%
(86/14), 54/46, 18/82; 15 h, 17%, 15% (19/81), 68% (86/14), 54/
46, 18/82; 16 h, 16%, 15% (21/79), 69% (86/14), 53/47, 18/82; 17
h, 15%, 15% (21/79), 70% (86/14), 50/50, 18/82; 20 h, 14%, 14%
(20/80), 72% (87/13), 50/50, 17/83. Although the ratio of 5f/6f after
16 h (53/47) was different from that after 17 h (50/50), those after
17 and 20 h were virtually the same. This is why it was concluded
that equilibrium between 5f/6f was attained in a range of time of
16-17 h (50/50). The changes of yields between 5f and 6f from
the early stage of this reaction indicated 6f was produced from 5f.
On the other hand, the equilibrium between 5f/6f was attained in
a range of time of 13-14 h (18/82). 5f: 31P NMR (160 MHz, CD2-
Cl2) δ 25.9 (d, JP-P ) 38 Hz, JPt-P ) 4037 Hz), 29.5 (d, JP-P ) 38
Hz, JPt-P ) 3516 Hz). cis-6f: 31P NMR (160 MHz, CD2Cl2) δ
15.2 (d, JP-P ) 20 Hz, the value of JPt-P was not readable because
of low intensity), 17.2 (d, JP-P ) 20 Hz, the value of JPt-P was not
readable because of low intensity). trans-6f: 31P NMR (160 MHz,
CD2Cl2) δ 16.4 (s, JPt-P ) 3241 Hz). syn-7f: 31P NMR (160 MHz,
CD2Cl2) δ 14.3 (s, JPt-P ) 4079 Hz). anti-7f: 31P NMR (160 MHz,
CD2Cl2) δ 16.1 (s, JPt-P ) 3964 Hz).
Reaction of trans-3a with 8 (eq 2). Into a dry Pyrex NMR tube
were added trans-3a (16.2 mg, 0.020 mmol), 8 (8.8 mg, 0.060
mmol), SdP(C6H4OMe-p)3 (3.6 mg, 0.0094 mmol), and CD2Cl2
(0.5 mL) under N2 atmosphere. Then the reaction was monitored
Reaction of 4g with 2 in C6D6 (run 12). The 31P NMR spectrum
showed the formation of 5g, trans-6g, and 7g. The reaction time,
the yields of 5g, trans-6g, and 7g (syn/anti), and the ratios of 5g/
trans-6g and trans-6g/7g at the time are as follows: 20 min, 51%,
5%, 44% (59/41), 91/9, 9/91; 40 min, 42%, 5%, 53% (60/40), 89/
11, 8/92; 1 h, 37%, 5%, 58% (64/36), 88/12, 8/92. Although the
ratio of 5g/trans-6g after 20 min (91/9) was different from that
after 40 min (89/11), those after 40 min and 1 h were virtually the
same. This is why it was concluded that equilibrium between 5g/
trans-6g was attained within 40 min (89/11). The equilibrium
1
by 31P and H NMR spectra at 25 °C. After 17 h, the 31P NMR
spectrum showed the formation of 5a (79%), trans-6a (0.6%), and
7a (13%, syn/anti ) 77/23). anti-7a: 31P NMR (160 MHz, CD2-
Cl2) δ 17.0 (s, JPt-P ) 4013 Hz).
Reaction of 4c with 2 in Toluene-d8 at Low Temperature (eq
3). Into a dry Pyrex NMR tube were added 2 (15.8 mg, 0.021
mmol), 4c (13.2 mg, 0.069 mmol), and SdP(C6H4OMe-p)3 (1.3

Reactions of R,â-Unsaturated Thioesters with Pt(0)
Organometallics, Vol. 25, No. 12, 2006 2957
mg, 0.0034 mmol). Then ca. 0.5 mL of toluene-d8 was transferred
by the freeze-pump-thaw method. The 31P NMR spectrum showed
the formation of two π-complexes, 5c (5c1 and 5c2), trans-6c, and
7c. The reaction temperature and time and the yields of 2, 5c (5c1/
5c2), trans-6c, and 7c at the time are as follows: -70 °C, 10 min,
81%, 19% (63/37), 0%, 0%; -10 °C, 10 min, 0%, 92% (96/4),
5%, 3% (67/33); 0 °C, 10 min, 0%, 74% (100/0), 11%, 14% (79/
21); 25 °C, 0%, 9% (100/0), 4%, 87% (61/39). 2: 31P NMR (160
MHz, toluene-d8) δ 34.9 (s, JPt-P ) 3658 Hz). 5c1: 31P NMR (160
MHz, toluene-d8) δ 29.9 (d, JP-P ) 44 Hz, JPt-P ) 4208 Hz), 31.2
(d, JP-P ) 44 Hz, JPt-P ) 3373 Hz). 5c2: 31P NMR (160 MHz,
toluene-d8) δ 29.4 (d, JP-P ) 41 Hz, JPt-P ) 3280 Hz), 30.1 (d,
JP-P ) 41 Hz, JPt-P ) 4212 Hz). trans-6c: 31P NMR (160 MHz,
toluene-d8) δ 17.9 (s, JPt-P ) 3304 Hz). syn-7c: 31P NMR (160
MHz, toluene-d8) δ 15.9 (s, JPt-P ) 4213 Hz). anti-7c: 31P NMR
(160 MHz, toluene-d8) δ 17.8 (s, JPt-P ) 4050 Hz).
Reaction of 4g with 2 in Toluene-d8 at Low Temperature (eq
4). Into a dry Pyrex NMR tube were added 2 (15.1 mg, 0.020
mmol), 4g (5.7 mg, 0.022 mmol), and SdP(C6H4OMe-p)3 (0.9 mg,
0.0023 mmol). Then ca. 0.5 mL of toluene-d8 was transferred by
the freeze-pump-thaw method. The 31P NMR spectrum showed
the formation of 5g, 6g, and 7g. The reaction temperature and time
and the yields of 2, 5g, 6g, and 7g at the time are as follows: -50
°C, 10 min, 78%, 22%, 0%, 0%; -30 °C, 10 min, 32%, 63%, 5%
(60/40), 0%; 10 °C, 10 min, 0%, 87%, 5% (0/100), 6.6 (91/9); 25
°C, 2 h, 0%, 61%, 4% (0/100), 35% (60/40). These results clearly
showed that 5g was a kinetic product, which isomerized to cis-6g
then trans-6g and 7g. 5g: 31P NMR (160 MHz, toluene-d8) δ 27.2
(d, JP-P ) 37 Hz, JPt-P ) 4124 Hz), 28.1 (d, JP-P ) 37 Hz, JPt-P
) 3597 Hz). cis-6g: 31P NMR (160 MHz, toluene-d8) δ 17.1 (d,
JP-P ) 21 Hz, the value of JPt-P was not readable because of low
intensity), 19.1 (d, JP-P ) 21 Hz, the value of JPt-P was not readable
because of low intensity). trans-6g: 31P NMR (160 MHz, toluene-
d8) δ 17.6 (s, JPt-P ) 3277 Hz). syn-7g: 31P NMR (160 MHz,
toluene-d8) δ 15.8 (s, JPt-P ) 4189 Hz). anti-7g: 31P NMR (160
MHz, toluene-d8) δ 17.5 (s, the value of JPt-P was not readable
because of low intensity).
be 36 min. The present result did not contradict the idea that the
transformation from 5h to 6h was a unimolecular process.
Half-Life of the Reaction of 5h to 6h in CD2Cl2 (run 3). The
31P NMR spectrum showed the formation of 5h and 6h. The
reaction time (the average of acquisition time) and the yields of
5h and 6h at the time were 10 min, 69%, 30% (cis/trans ) 67/33);
20 min, 44%, 54% (cis/trans ) 42/58); 30 min, 29%, 70% (cis/
trans ) 30/70); 40 min, 17%, 81% (cis/trans ) 20/80); 50 min,
12%, 87% (cis/trans ) 12/88); 60 min, 7%, 92% (cis/trans ) 9/91);
70 min, 4%, 94% (cis/trans ) 7/93); 80 min, 2%, 96% (cis/trans
) 6/94); 2 h, 0%, 99% (cis/trans ) 3/97). The consumption rate
of 5h obeyed first-order kinetics, and the half-life was calculated
to be 14 min. 5h: 31P NMR (160 MHz, CD2Cl2) δ 27.2 (d, JP-P
)
36 Hz, JPt-P ) 4025 Hz), 30.0 (d, JP-P ) 36 Hz, JPt-P ) 3667
Hz). cis-6h: 31P NMR (160 MHz, CD2Cl2) δ 14.1 (d, JP-P ) 18
Hz, JPt-P ) 1336 Hz), 17.0 (d, JP-P ) 18 Hz, JPt-P ) 3765 Hz).
trans-6h: 31P NMR (160 MHz, CD2Cl2) δ 15.1 (s, JPt-P ) 3225
Hz).
Half-Life of the Reaction of 5h to 6h in Acetone-d6 (run 4).
The 31P NMR spectrum showed the formation of 5h and 6h. The
reaction time (the average of acquisition time) and the yields of
5h and 6h at the time were 3.0 min, 92%, 8% (cis/trans ) 88/12);
4.0 min, 89%, 11% (cis/trans ) 68/32); 5.0 min, 85%, 15% (cis/
trans ) 60/40); 6.0 min, 81%, 19% (cis/trans ) 59/41); 8.0 min,
76%, 24% (cis/trans ) 49/51); 18 min, 54%, 46% (cis/trans )
27/63); 20 min, 50%, 50% (cis/trans ) 28/72); 30 min, 34%, 67%
(cis/trans ) 16/84); 40 min, 25%, 75% (cis/trans ) 11/89); 50
min, 17%, 83% (cis/trans ) 7/93); 60 min, 9%, 91% (cis/trans )
4/96); 70 min, 6%, 94% (cis/trans ) 4/96). The consumption rate
of 5h obeyed first-order kinetics, and the half-life was calculated
to be 19 min. 5h: 31P NMR (160 MHz, acetone-d6) δ 27.8 (d, JP-P
) 36 Hz, JPt-P ) 3882 Hz), 30.8 (d, JP-P ) 36 Hz, JPt-P ) 3672
Hz). cis-6h: 31P NMR (160 MHz, acetone-d6) δ 15.7 (d, JP-P ) 19
Hz, the value of JPt-P was not readable because of low intensity),
19.3 (d, JP-P ) 19 Hz, the value of JPt-P was not readable because
of low intensity). trans-6h: 31P NMR (160 MHz, acetone-d6) δ 15.8
(s, JPt-P ) 3243 Hz).
Half-Life of the Reaction of 5h to 6h in THF-d8 (run 5). The
31P NMR spectrum showed the formation of 5h and 6h. The
reaction time (the average of acquisition time) and the yields of
5h and 6h at the time were 4.0 min, 98%, 2% (cis/trans ) 0/100);
5.0 min, 96%, 4% (cis/trans ) 0/100); 6.0 min, 95%, 5% (cis/
trans ) 0/100); 8.0 min, 90%, 10% (cis/trans ) 31/69); 9.0 min,
89%, 11% (cis/trans ) 30/70); 20 min, 74%, 26% (cis/trans )
15/85); 30 min, 63%, 37% (cis/trans ) 10/90); 40 min, 52%, 48%
(cis/trans ) 8/92); 50 min, 40%, 60% (cis/trans ) 5/95); 60 min,
34%, 66% (cis/trans ) 0/100); 70 min, 28%, 72% (cis/trans )
0/100). The consumption rate of 5h obeyed first-order kinetics, and
the half-life was calculated to be 36 min. 5h: 31P NMR (160 MHz,
THF-d8) δ 29.0 (d, JP-P ) 37 Hz, JPt-P ) 3983 Hz), 32.0 (d, JP-P
) 37 Hz, JPt-P ) 3678 Hz). cis-6h: 31P NMR (160 MHz, THF-d8)
δ 16.0 (d, JP-P ) 18 Hz, the value of JPt-P was not readable because
of low intensity), 19.2 (d, JP-P ) 18 Hz, the value of JPt-P was not
readable because of low intensity). trans-6h: 31P NMR (160 MHz,
THF-d8) δ 16.5 (s, JPt-P ) 3224 Hz).
Half-Life of the Reaction of 5i to 6i in C6D6 (run 6). Into a
dry Pyrex NMR tube were added 1 (15.0 mg, 0.020 mmol), 4i (4.9
mg, 0.022 mmol), SdP(C6H4OMe-p)3 (1.0 mg, 0.0027 mmol), and
C6D6 (0.5 mL) under N2 atmosphere. Then the reaction was
monitored by 31P and 1H NMR spectra at 25 °C. The reaction time
(the average of acquisition time) and the yields of 5i and trans-6i
at the time were 2.0 min, 8.3%, 85.7%; 2.5 min, 8.2%, 90.0%; 3.0
min, 7.8%, 92.2%; 3.5 min, 7.2%, 92.8%; 4.0 min, 5.5%, 94.5%;
4.5 min, 4.8%, 95.2%; 5.0 min, 3.6%, 96.4%; 5.5 min, 3.0%, 93.2%;
6.0 min, 2.7%, 96.8%; 6.5 min, 2.2%, 90.5%; 7.0 min, 0%, 100%.
The consumption rate of 5i obeyed first-order kinetics, and the half-
life was calculated to be ca. 2.1 min. 5i: 31P NMR (160 MHz, C6D6)
Half-Life of the Reaction of 5h to 6h in C6D6 (run 1 of Table
2). The 31P NMR spectrum showed the formation of 5h and 6h.
The reaction time (the average of acquisition time) and the yields
of 5h and 6h at the time were 20 min, 75%, 25% (cis/trans )
13/87); 30 min, 62%, 38% (cis/trans ) 7/93); 40 min, 51%, 49%
(cis/trans ) 4/96); 50 min, 42%, 57% (cis/trans ) 3/97); 60 min,
35%, 64% (cis/trans ) 3/97); 70 min, 29%, 71% (cis/trans ) 3/97);
80 min, 24%, 76% (cis/trans ) 1/99); 120 min, 11%, 89% (trans
only); 180 min, 4%, 96% (trans only); 6 h, 0%, 100% (trans only).
The consumption rate of 5h obeyed first-order kinetics (ln{[5h]0/
[5h]t} ) kt) and the half-life was calculated to be 38 min. All
reactions shown in Table 2 were carried out similarly. 5h: 31P NMR
(160 MHz, C6D6) δ 27.6 (d, JP-P ) 38 Hz, JPt-P ) 3863 Hz), 30.6
(d, JP-P ) 38 Hz, JPt-P ) 3683 Hz). cis-6h: 31P NMR (160 MHz,
C6D6) δ 14.5 (d, JP-P ) 18 Hz, the value of JPt-P was not readable
because of low intensity), 17.9 (d, JP-P ) 18 Hz, the value of JPt-P
was not readable because of low intensity). trans-6h: 31P NMR
(160 MHz, C6D6) δ 15.1 (s, JPt-P ) 3228 Hz).
Half-Life of the Reaction of 5h to 6h Using 4.5 Equiv of 4h
in C6D6 (run 2). The 31P NMR spectrum showed the formation of
5h and 6h. The reaction time (the average of acquisition time) and
the yields of 5h and 6h at the time were 12 min, 82%, 18% (cis/
trans ) 19/81); 20 min, 72%, 28% (cis/trans ) 9/91); 30 min,
60%, 40% (cis/trans ) 5/95); 40 min, 50%, 50% (cis/trans ) 2/98);
50 min, 41%, 59% (cis/trans ) 4/96); 60 min, 33%, 67% (cis/
trans ) 3/97); 70 min, 27%, 73% (trans only); 80 min, 22%, 78%
(trans only); 120 min, 12%, 88% (trans only); 180 min, 3%, 97%
(trans only); 9 h, 0%, 100% (trans only). The consumption rate of
5h obeyed first-order kinetics, and the half-life was calculated to

2958 Organometallics, Vol. 25, No. 12, 2006
Minami et al.
δ 29.1 (d, JP-P ) 42 Hz, the value of JPt-P was not readable because
of low intensity), 30.3 (d, JP-P ) 42 Hz, the value of JPt-P was not
readable because of low intensity). trans-6i: 31P NMR (160 MHz,
C6D6) δ 16.3 (s, JPt-P ) 3268 Hz).
reaction time (the average of acquisition time) and the yields of
5k and 6k at the time were 2 min, 32%, 68% (cis/trans ) 58/42);
4 min, 8%, 86% (cis/trans ) 34/66); 5 min, 4%, 90% (cis/trans )
24/76); 6 min, 3%, 91% (cis/trans ) 20/80); 7 min, 2%, 92% (cis/
trans ) 15/85); 20 min, 0%, 97% (cis/trans ) 2/98). The
consumption rate of 5k obeyed first-order kinetics, and the half-
life was calculated to be 1.2 min. 5k: 31P NMR (160 MHz, CD2-
Cl2) δ 25.7 (d, JP-P ) 35 Hz, the value of JPt-P was not readable
because of low intensity of the signal), 29.2 (d, JP-P ) 35 Hz, the
value of JPt-P was not readable because of low intensity of the
signal). cis-6k: 31P NMR (160 MHz, CD2Cl2) δ 13.9 (d, JP-P ) 19
Hz, JPt-P ) 1328 Hz), 17.1 (d, JP-P ) 19 Hz, JPt-P ) 3720 Hz).
trans-6k: 31P NMR (160 MHz, CD2Cl2) δ 14.6 (s, JPt-P ) 3186
Hz).
Half-Life of the Reaction of 5i to 6i in CD2Cl2 (run 7). The
31P NMR spectrum showed the formation of 5i and trans-6i. The
reaction time (the average of acquisition time) and the yields of 5i
and trans-6i at the time were 2.0 min, 4.6%, 95.4%; 2.5 min, 3.6%,
96.4%; 3.0 min, 3.3%, 96.7%; 3.5 min, 2.9%, 97.1%; 4.0 min, 2.6%,
97.4%; 4.5 min, 2.5%, 97.5%; 5.0 min, 2.3%, 97.7%; 5.5 min, 2.2%,
97.8%; 6.0 min, 1.8%, 98.2%; 6.5 min, 1.6%, 98.4%; 7.0 min, 0%,
100%. The consumption rate of 5i obeyed first-order kinetics, and
the half-life was calculated to be ca. 3.3 min. 5i: 31P NMR (160
MHz, CD2Cl2) δ 28.7 (d, JP-P ) 40 Hz, the value of JPt-P was not
readable because of low intensity), 29.7 (d, JP-P ) 40 Hz, the value
of JPt-P was not readable because of low intensity). trans-6i: 31P
NMR (160 MHz, CD2Cl2) δ 16.3 (s, JPt-P ) 3258 Hz).
Half-Life of the Reaction of 5l to 6l in C6D6 (run 13). The 31
P
NMR spectrum showed the formation of 5l and trans-6l. The
reaction time (the average of acquisition time) and the yields of 5l
and trans-6l at the time were 10 min, 41%, 59%; 20 min, 21%,
74%; 30 min, 11%, 86%; 40 min, 4%, 92%; 50 min, 2%, 95%; 60
min, 1%, 95%; 3 h, 0%, 95%. The consumption rate of 5l obeyed
first-order kinetics, and the half-life was calculated to be 9.1 min.
Half-Life of the Reaction of 5j to 6j in C6D6 (run 8). The 31
P
NMR spectrum showed the formation of 5j and trans-6j. The
reaction time (the average of acquisition time) and the yields of 5j
and trans-6j at the time were 10 min, 90%, 10%; 20 min, 78%,
21%; 30 min, 66%, 32%; 40 min, 57%, 42%; 50 min, 48%, 49%;
60 min, 42%, 52%; 70 min, 34%, 63%; 80 min, 29%, 68%; 24 h,
0%, 98%. The consumption rate of 5j obeyed first-order kinetics,
and the half-life was calculated to be 43 min. 5j: 31P NMR (160
MHz, C6D6) δ 26.5 (d, JP-P ) 35 Hz, JPt-P ) 3909 Hz), 30.1 (d,
JP-P ) 35 Hz, JPt-P ) 3697 Hz). trans-6j: 31P NMR (160 MHz,
C6D6) δ 14.8 (s, JPt-P ) 3192 Hz).
Half-Life of the Reaction of 5j to 6j Using 5.0 Equiv of 4j in
C6D6 (run 9). The 31P NMR spectrum showed the formation of 5j
and trans-6j. The reaction time (the average of acquisition time)
and the yields of 5j and trans-6j at the time were 5 min, 93%, 7%;
6 min, 92%, 8%; 8 min, 88%, 10%; 10 min, 85%, 13%; 20 min,
73%, 23%; 30 min, 62%, 34%; 40 min, 54%, 42%; 50 min, 45%,
50%; 60 min, 38%, 57%; 70 min, 32%, 63%; 80 min, 28%, 67%.
The consumption rate of 5j obeyed first-order kinetics, and the half-
life was calculated to be 43 min, showing that the transformation
from 5j to 6j was a unimolecular process.
Half-Life of the Reaction of 5j to 6j in CD2Cl2 (run 10). The
31P NMR spectrum showed the formation of 5j and 6j. The reaction
time (the average of acquisition time) and the yields of 5j and 6j
at the time were 4 min, 72%, 28% (cis/trans ) 69/31); 5 min, 63%,
37% (cis/trans ) 60/40); 6 min, 60%, 40% (cis/trans ) 56/44); 7
min, 56%, 44% (cis/trans ) 53/47); 8 min, 51%, 47% (cis/trans
) 48/52); 10 min, 43%, 54% (cis/trans ) 41/59); 20 min, 15%,
79% (cis/trans ) 18/82); 30 min, 5%, 92% (cis/trans ) 10/90);
40 min, 0%, 97% (cis/trans ) 5/95). The consumption rate of 5j
obeyed first-order kinetics, and the half-life was calculated to be
6.8 min. 5j: 31P NMR (160 MHz, CD2Cl2) δ 26.0 (d, JP-P ) 35
Hz, JPt-P ) 3938 Hz), 29.8 (d, JP-P ) 35 Hz, JPt-P ) 3684 Hz).
cis-6j: 31P NMR (160 MHz, CD2Cl2) δ 14.2 (d, JP-P ) 19 Hz,
JPt-P ) 1311 Hz), 17.3 (d, JP-P ) 19 Hz, JPt-P ) 3824 Hz). trans-
6j: 31P NMR (160 MHz, CD2Cl2) δ 14.7 (s, JPt-P ) 3239 Hz).
Half-Life of the Reaction of 5k to 6k in C6D6 (run 11). The
31P NMR spectrum showed the formation of 5k and trans-6k. The
reaction time (the average of acquisition time) and the yields of
5k and trans-6k at the time were 2 min, 25%, 75%; 4 min, 21%,
79%; 6 min, 15%, 85%; 8 min, 12%, 88%; 10 min, 9%, 91%; 12
min, 8%, 88%; 14 min, 7%, 88%; 37 min, 0%, 100%. The
consumption rate of 5k obeyed first-order kinetics, and the half-
life was calculated to be 6.2 min. 5k: 31P NMR (160 MHz, C6D6)
δ 26.2 (d, JP-P ) 37 Hz, the value of JPt-P was not readable because
of low intensity of the signal), 29.9 (d, JP-P ) 37 Hz, the value of
5l: 31P NMR (160 MHz, C6D6) δ 26.7 (d, JP-P ) 36 Hz, JPt-P
)
4178 Hz), 27.4 (d, JP-P ) 36 Hz, JPt-P ) 3552 Hz). trans-6l: 31P
NMR (160 MHz, C6D6) δ 16.0 (s, JPt-P ) 3229 Hz).
Half-Life of the Reaction of 5l to 6l Using 4.7 Equiv of 4l in
C6D6 (run 14). The 31P NMR spectrum showed the formation of
5l and trans-6l. The reaction time (the average of acquisition time)
and the yields of 5l and trans-6l at the time were 10 min, 40%,
58%; 20 min, 23%, 75%; 30 min, 13%, 83%; 40 min, 6%, 86%;
50 min, 2%, 90%; 60 min, 1%, 94%; 70 min, 0%, 92%. The
consumption rate of 5l obeyed first-order kinetics, and the half-
life was calculated to be 9.1 min. The present result did not
contradict the idea that the transformation from 5l to 6l was a
unimolecular process.
Half-Life of the Reaction of 5l to 6l in CD2Cl2 (run 15). The
31P NMR spectrum showed the formation of 5l and 6l. The reaction
time (the average of acquisition time) and the yields of 5l and 6l at
the time were 10 min, 31%, 69% (cis/trans ) 1/99); 20 min, 12%,
88% (cis/trans ) 2/98); 30 min, 6%, 94% (cis/trans ) 2/98); 40
min, 2%, 98% (trans only); 50 min, 0%, 100% (trans only). The
consumption rate of 5l obeyed first-order kinetics, and the half-
life was calculated to be 7.8 min. 5l: 31P NMR (160 MHz, CD2-
Cl2) δ 26.3 (d, JP-P ) 35 Hz, JPt-P ) 4208 Hz), 26.7 (d, JP-P ) 35
Hz, JPt-P ) 3525 Hz). cis-6l: 31P NMR (160 MHz, CD2Cl2) δ 14.1
(d, JP-P ) 19 Hz, the value of JPt-P was not readable because of
low intensity), 17.8 (d, JP-P ) 19 Hz, the value of JPt-P was not
readable because of low intensity). trans-6l: 31P NMR (160 MHz,
CD2Cl2) δ 16.1 (s, JPt-P ) 3217 Hz).
Reaction of 4k with 2 in CD2Cl2 at Low Temperature. Into a
dry Pyrex NMR tube were added 2 (15.2 mg, 0.020 mmol), 4k
(6.4 mg, 0.022 mmol), and SdP(C6H4OMe-p)3 (1.1 mg, 0.0028
mmol). Then ca. 0.5 mL of CD2Cl2 was transferred by the freeze-
pump-thaw method. The 31P NMR spectrum showed the formation
of 5k and 6k. The reaction temperature and time (the average of
acquisition time) and the yields of 2, 5k, and 6k (cis/trans) at the
time are as follows: -50 °C, 10 min, 30%, 70%, 0%; -40 °C, 10
min, 20%, 77%, 3% (100/0); -10 °C, 10 min, 9%, 67%, 24% (92/
8); 25 °C, 1 h, 0%, 0%, 100% (0/100). These results clearly showed
that 5k was a kinetic product, which selectively isomerized to cis-
6k then trans-6k. 2: 31P NMR (160 MHz, CD2Cl2) δ 33.5 (s, JPt-P
) 3617 Hz).
Activation Parameters (Table 3). Activation parameters of the
transformation of 5h to 6h, 5j to 6j, and 5l to 6l were calculated
by measuring the temperature dependence of reaction rates in the
range from 20 to 40 °C in both C6D6 and CD2Cl2 according to the
equation k ) (kBT/h){exp[-(∆Hq - T∆Sq)/(RT)]}.
J
Pt-P was not readable because of low intensity of the signal). trans-
6k: 31P NMR (160 MHz, C6D6) δ 14.8 (s, JPt-P ) 3206 Hz).
Half-Life of the Reaction of 5k to 6k in CD2Cl2 (run 12).
The 31P NMR spectrum showed the formation of 5k and 6k. The

Reactions of R,â-Unsaturated Thioesters with Pt(0)
Organometallics, Vol. 25, No. 12, 2006 2959
Activation Parameters of the Transformation of 5h to 6h in
C6D6. Reaction temperature and reaction rates were as follows: 298
K, 0.000307 s-1; 303 K, 0.000538 s-1; 308 K, 0.00112 s-1; 313
K, 0.000633 s-1; 298 K, 0.00127 s-1; 303 K, 0.00171 s-1; 308 K,
0.00267 s-1
.
Activation Parameters of the Transformation of 5l to 6l in
K, 0.00233 s-1
.
CD2Cl2. Reaction temperature and reaction rates were as follows:
Activation Parameters of the Transformation of 5h to 6h in
293 K, 0.000750 s-1; 298 K, 0.00149 s-1; 303 K, 0.00169 s-1
;
CD2Cl2. Reaction temperature and reaction rates were as follows:
308 K, 0.00471 s-1
.
298 K, 0.000822 s-1; 303 K, 0.00131 s-1; 308 K, 0.00178 s-1
;
313 K, 0.00255 s-1
.
Acknowledgment. We thank the Instrumental Analysis
Center, Faculty of Engineering, Osaka University, for elemental
analysis.
Activation Parameters of the Transformation of 5j to 6j in
C6D6. Reaction temperature and reaction rates were as follows: 298
K, 0.000270 s-1; 303 K, 0.000422 s-1; 308 K, 0.000773 s-1; 313
K, 0.00133 s-1
.
Activation Parameters of the Transformation of 5j to 6j in
CD2Cl2. Reaction temperature and reaction rates were as follows:
298 K, 0.00171 s-1; 303 K, 0.00194 s-1; 308 K, 0.00267 s-1; 313
Supporting Information Available: Complete description of
the X-ray crystallographic structure determination of 7g. Crystal-
lographic data in CIF format are also given. This material is
available free of charge via the Internet at http://pubs.acs.org.
K, 0.00408 s-1
.
Activation Parameters of the Transformation of 5l to 6l in
C6D6. Reaction temperature and reaction rates were as follows: 293
OM050834W