Preparation, properties, and catalytic activity of transition-metal complexes containing a ligated 2-methyl-3,3-diphenyl-1,3-diphosphapropene skeleton

Article abstract of DOI:10.1016/j.tetlet.2003.09.073

2-Methyl-3,3-diphenyl-1-(2,4,6-tri-t-butylphenyl)-1,3-diphosphapropene behaved as an unsymmetrical chelating ligand for transition metal complexes and the 1,3-diphosphapropene moiety was hydrolyzed to afford the 1,3-diphosphapropan-1-ol derivative upon coordination. The palladium complex showed catalytic activity for the Sonogashira coupling reaction.

Full text of DOI:10.1016/j.tetlet.2003.09.073

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 44 (2003) 8297–8300
Preparation, properties, and catalytic activity of transition-metal
complexes containing a ligated
2-methyl-3,3-diphenyl-1,3-diphosphapropene skeleton
Hongze Liang, Katsunori Nishide, Shigekazu Ito and Masaaki Yoshifuji*
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba, Sendai 980-8578, Japan
Received 30 June 2003; revised 8 August 2003; accepted 5 September 2003
Abstract—2-Methyl-3,3-diphenyl-1-(2,4,6-tri-t-butylphenyl)-1,3-diphosphapropene behaved as an unsymmetrical chelating ligand
for transition metal complexes and the 1,3-diphosphapropene moiety was hydrolyzed to afford the 1,3-diphosphapropan-1-ol
derivative upon coordination. The palladium complex showed catalytic activity for the Sonogashira coupling reaction.
© 2003 Elsevier Ltd. All rights reserved.
We have recently reported preparation of a bulky 2-
(Z)-2-Bromo-1-(2,4,6-tri-t-butylphenyl)-1-phosphaprop-
ene (Z-2)7 was allowed to react successively with butyl-
lithium and chlorodiphenylphosphine to give (E)-2-
methyl-1,3-diphosphapropene E-3 in 66% yield
(Scheme 1).8 In this reaction, Z-3 seemed to be unstable
and isomerized to E-3 probably due to the steric repul-
sion between the Mes* and the Ph2P groups as we
observed for 1.1 The E/Z isomerization of E-3 was
observed upon heating (100°C in toluene) to afford a
mixture of 3 in E/Z=2:1 ratio,8 whereas no isomeriza-
tion of 1 was observed under similar conditions.1
Attempts to isolate Z-3 by means of chromatography
failed due to its instability on silica gel.
chloro-1,3-diphosphapropene Mes*P=C(Cl)PPh2 (1;
Mes*=2,4,6-t-Bu3C6H2) as
a primitive compound
involving an unsaturated sp2 phosphorus and a normal
sp3 phosphino group.1 Basically, 1 takes the Z configu-
ration to avoid the steric congestion between the Mes*
group and the PPh2 moiety, which is advantageous to
act as a chelate ligand. The 1,3-diphosphapropene
skeleton behaves like an unsymmetrical chelating ligand
and displays a stepwise coordination nature on the
tungsten(0) metal.1 On the other hand, 1 did not afford
any palladium or platinum complexes. Some phospho-
rus-carbon double-bondings were reported to be acti-
vated on coordination to the transition metals to cause
saturation of the PꢀC bond2 leading to an undesired
reaction of 1 with a palladium or a platinum reagent.
We3 and others4 have utilized several low-coordinated
phosphorus compounds for ligands of synthetic cata-
lysts containing palladium or platinum, and we were
prompted to explore 1,3-diphosphapropene derivatives
which afford the corresponding palladium or platinum
complexes.5 We here report that a 3-methyl-3,3-
diphenyl-1,3-diphosphapropene derivative afforded the
corresponding chelate palladium(II) complex which cat-
alyzed the Sonogashira coupling reaction.6 In the
course of the research, we also found that the PꢀC
moiety was activated by palladium or platinum leading
to the corresponding adduct upon hydrolysis.
First of all, the coordination ability of E-3 was studied.
Compound E-3 was allowed to react with W(CO)5(thf)
to afford monocoordinated complex 4 in 70% yield
together with a small amount of chelate complex 5 (3%
yield).9 Furthermore, 4 was irradiated to afford 5 in
29% yield from 4 by releasing one CO ligand (Scheme
2).9 In contrast to E-3, E/Z isomerization of 4 was not
observed upon heating. The molecular structure of 5
was nearly homologous to the corresponding tung-
sten(0) complex of 1 (Fig. 1).10
Keywords: phosphaalkenes; kinetic stabilization; chelate ligand; Sono-
gashira coupling.
* Corresponding author. Fax: (+81) 22 217 6562; e-mail: yoshifj@
mail.tains.tohoku.ac.jp
Scheme 1. Preparation of E-3 from Z-2.
0040-4039/$ - see front matter © 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2003.09.073

8298
H. Liang et al. / Tetrahedron Letters 44 (2003) 8297–8300
oxide.14 The geometry around the palladium in 8
reveals a distorted square form while the Pd–P1–C1–P2
,
ring is almost planar. The Cl2–Pd bond, 2.3970(9) A, is
longer than that of Cl1–Pd, 2.3846(9) A, indicating the
,
greater trans effect of the P1 moiety compared with the
PPh2 group. The hydroxyl group in 8 displayed a
hydrogen bond with water in the crystal showing the
intermolecular H15…OH2 distance of 1.57 A. The P1–
O1 bond, 1.567(3) A, is similar to the ‘P–O(H)’ value in
,
,
15
,
[H(Ph2PO)2Au]2 (1.561(5) A). The P1 atom remark-
ably deviates from the Mes* plane, as indicated in the
torsion angles of P1–Cipso–Cortho–Ct-Bu [54.1(5) and
51.9(5)°], due to relief of the steric congestion. As for
E-3, no hydrolyzed product was obtained suggesting
that the palladium moiety enhances the reactivity of the
P=C part. Although the detailed mechanism for the
hydrolysis affording 8 is uncertain so far, the palladium
atom might promote the syn-addition of water.16 Com-
plex 8 decomposed in chloroform in several hours to
give 1,3,5-tri-t-butylbenzene, indicating the instability
of 8 in the presence of a trace of acid.17 Similarly, 7
afforded a hydrolyzed product 9 on silica gel (Fig.
2b).18,19 The geometry around the platinum displays a
Scheme 2. Preparation of tungsten(0), palladium(II), and
platinum(II) complexes from E-3.
,
planar square. The distance of the Cl1–Pt [2.368(4) A]
,
is longer than that of the Cl2–Pt [2.352(4) A], which is
similar to the geometries of 8. The P1–O1 distance was
,
observed by 1.60(2) A.
Figure 1. Molecular structure of 5. The hydrogen atoms are
omitted for clarity. The p-t-butyl group in the Mes* group is
disordered and atoms with predominant occupancy factor
(0.62) are shown.
In contrast to 1, E-3 formed palladium(II) and plat-
inum(II) complexes: E-3 was allowed to react with
PdCl2(CH3CN)2 to afford the corresponding palla-
dium(II) complex 6.11 The result suggests that the coor-
dination properties of the 1,3-diphosphapropene ligand
strongly depend on the substituents. In the 31P NMR
spectrum, the sp2 phosphorus in 6 shifted to a higher
field than that of E-3, which still falls within the region
of PꢀC resonance, indicating the end-on coordination
(Scheme 2). Additionally, a platinum(II) complex 7 [lP
2
195.9 (1JPPt=3898 Hz), −22.4 (1JPPt=2887 Hz), JPP=
50 Hz] was also obtained by a similar reaction with
PtCl2(cycloocta-1,5-diene).
When 6 was allowed to react with an excess amount of
water in THF/dichloromethane for 40 h, 8 was
obtained almost quantitatively (Scheme 2).12 Indeed,
when we dissolved the powdered 8 in a 1:1 mixture of
dichloromethane and ‘wet’ THF, pale-yellow prisms of
8 were formed at 0°C after a week. Figure 2a displays
the molecular structure of 8 indicating that the addition
of water occurred on the PꢀC bond in the syn fashion
to give the meso isomers.13 The solvent molecules, water
and dichloromethane, were involved in the crystal, and
indeed a transparent prism of 8 became an opaque solid
in the air, probably due to loss of the involved solvents
from the crystal lattice. Compound 8 is stable in the air
and did not seem to be in an equilibrium of the
Arbuzov type with the corresponding phosphine
Figure 2. (a) Molecular structure of 8. The hydrogen atoms
except for H1 and H15 and the solvent molecules (CH2Cl2,
H2O) are omitted for clarity. The p-t-butyl group in the Mes*
group is disordered and atoms with predominant occupancy
factor (0.56) are shown. (b) Molecular structure of 9. The
hydrogen atoms except for OH and CH (C1) and the solvent
molecules (C2H5OH, C4H8O) are omitted for clarity. The
atoms in the p-t-butyl group are refined isotropically.

H. Liang et al. / Tetrahedron Letters 44 (2003) 8297–8300
Table 1. Sonogashira coupling reaction (Eq. (1))a
8299
Entry
Catalyst
ArX
R
Base
Temp.
Time (h)
Yield (%)
1
2
3
4
5
6
7
6/CuI
6/CuI
6
6/CuI
6/CuI
6/CuI
6/CuI
PhI
PhI
PhI
PhI
Ph
Ph
Ph
SiMe3
Ph
Et3N
Et2NH
Et3N
Et3N
Et3N
Et3N
Et3N
rt
rt
rt
rt
rt
rt
Reflux
4
4
4
4
4
99
49
11
93
4
2-PyBr
p-O2NC6H4Br
PhBr
b
Ph
Ph
4
17
–
4
a Reaction conditions: iodobenzene (2.0 mmol), phenylacetylene (2.0 mmol), 6 (0.050 mmol), copper(I) iodide (0.050 mmol), base (8 mL).
b PhCꢁCꢂCꢁCPh was obtained in 18% isolated yield.
References
Secondly, to estimate the catalytic property of 6, we
studied the Sonogashira coupling reaction under the
original conditions, where a copper salt and a base6 are
employed (Eq. (1)).20 As shown in Table 1, 6 catalyzed
the coupling reaction of iodobenzene and acetylenes at
room temperature to afford the corresponding acetyle-
nes in moderate to excellent yields (Entry 1, 2 and 4).
Copper(I) iodide was essential for the reaction to pro-
ceed, and triethylamine gave better results than diethyl-
amine (Entry 2). As described in the literature,6 these
reaction conditions are mild and the experimental pro-
tocol is simple. We studied the Sonogashira coupling
with other aryl halides, but, unfortunately, no satisfac-
tory results were obtained. For example, 2-bromopy-
ridine and bromobenzene and phenylacetylene afforded
phenylacetylene in the presence of 6 under similar
conditions; however, the yields were low (Entry 5 and
7). Although we previously reported that a palla-
dium(II) complex containing ligated 3,4-diphosphini-
denecyclobutene catalyzed the Sonogashira reaction of
p-nitrobromobenzene with trimethylsilylacetylene under
refluxing diethylamine,3e the present complex 6 did not
catalyze this cross-coupling reaction. On the other
hand, phenylacetylene was homocoupled to afford
diphenylbutadiyne in the presence of p-nitrobromobenz-
ene, 6, copper(I) iodide and triethylamine (Entry 6).
These results indicate that 6 forms an intermediate
dialkynylpalladium(II) complex21 during the reaction,
and the mechanism of this coupling reaction might
include a different path from the established one. We
are now exploring reactions catalyzed by 6 in terms of
observation or isolation of the reaction intermediates.
Complex 8 can be considered to acted as a catalyst and
thus we are studying the properties of 8 as well as 9.15
1. Ito, S.; Yoshifuji, M. Chem. Commun. 2001, 1208.
2. (a) Appel, R.; Schuhn, W. J. Organomet. Chem. 1987,
329, 179; (b) Apkan, C. A.; Hitchcock, P. B.; Nixon, J.
F.; Yoshifuji, M.; Niitsu, T.; Inamoto, N. J. Organomet.
Chem. 1988, 338, C35.
3. (a) Ozawa, F.; Okamoto, H.; Kawagishi, S.; Yamamoto,
S.; Minami, T.; Yoshifuji, M. J. Am. Chem. Soc. 2002,
124, 10968; (b) Minami, T.; Okamoto, H.; Ikeda, S.;
Tanaka, R.; Ozawa, F.; Yoshifuji, M. Angew. Chem., Int.
Ed. 2001, 40, 4501; (c) Ozawa, F.; Yamamoto, S.;
Kawagishi, S.; Hiraoka, M.; Ikeda, S.; Minami, T.; Ito,
S.; Yoshifuji, M. Chem. Lett. 2001, 973; (d) Ikeda, S.;
Ohhata, F.; Miyoshi, M.; Tanaka, R.; Minami, T.;
Ozawa, F.; Yoshifuji, M. Angew. Chem., Int. Ed. 2000,
39, 4512; (e) Toyota, K.; Masaki, K.; Abe, T.; Yoshifuji,
M. Chem. Lett. 1995, 221; (f) Weber, L. Angew. Chem.,
Int. Ed. 2002, 41, 563.
4. (a) Ionkin, A.; Marshall, W. Chem. Commun. 2003, 710;
(b) Daugulis, O.; Brookhart, M.; White, P. S.
Organometallics 2002, 21, 5935; (c) Doux, M.; Me´zailles,
N.; Melaimi, M.; Ricard, L.; Le Floch, P. Chem. Com-
mun. 2002, 1566; (d) Breit, B.; Winde, R.; Mackewitz, T.;
Paciello, P.; Harms, K. Chem. Eur. J. 2001, 7, 3106; (e)
Keim, W.; Appel, R.; Gruppe, S.; Knoch, F. Angew.
Chem., Int. Ed. Engl. 1987, 26, 1012.
5. Liang, H.; Ito, S.; Yoshifuji, M. Org. Biomol. Chem.
2003, 1, 3054.
6. (a) Sonogashira, K. In Metal-Catalyzed Cross-Coupling
Reactions; Diederich, F.; Stang, P. J., Eds.; Wiley-VCH:
Weinheim, 1998; (b) Sonogashira, K.; Tohda, Y.; Hagi-
hara, N. Tetrahedron Lett. 1975, 4467.
7. (a) Ito, S.; Kimura, S.; Yoshifuji, M. Chem. Lett. 2002,
708; (b) Ito, S.; Kimura, S.; Yoshifuji, M. Bull. Chem.
Soc. Jpn. 2003, 76, 405.
8. NMR data for E-3: 31P{1H} NMR (162 MHz, CDCl3) l
(1)
294.4 (d, JPP 266 Hz), 9.2 (d, JPP 266 Hz); 1H NMR
(400 MHz, CDCl3) l 7.52–7.56 (4H, m, arom), 7.43 (2H,
m, arom), 7.40–7.28 (6H, m, arom), 1.50 (18H, s, o-t-Bu),
2
2
3
3
Acknowledgements
1.43 (3H, dd, JPH 14 Hz, JPH 8 Hz, Me), 1.36 (9H, s,
p-t-Bu); 13C{1H} NMR (101 MHz, CDCl3) l 181.0 (dd,
1JPC 59 Hz, JPC 30 Hz, PꢀC), 153.8 (s, o-Mes*), 150.4 (s,
1
1
3
p-Mes*), 139.6 (dd, JPC 69 Hz, JPC 26 Hz, ipso-Mes*),
This work was supported in part by Grants-in-Aid for
Scientific Research (No. 13304049 and 14044012) from
the Ministry of Education, Culture, Sports, Science and
Technology, Japan. H.L. is grateful to the Japan Soci-
ety for the Promotion of Science for a Postdoctoral
Fellowship for Foreign Researchers.
137.4 (pt, (1JPC+3JPC)/2 15 Hz, ipso-Ph), 134.3 (d, JPC 19
2
3
Hz, o-Ph), 129.3 (s, p-Ph), 128.9 (d, JPC 7 Hz, m-Ph),
122.3 (s, m-Mes*), 38.6 (s, o-CMe3), 35.6 (s, p-CMe3),
4
33.5 (d, JPC 7 Hz, o-CMe3), 32.1 (s, p-CMe3), 22.6 (dd,
2JPC 15 Hz, JPC 9 Hz, Me). NMR data for Z-3: 31P{1H}
2

8300
H. Liang et al. / Tetrahedron Letters 44 (2003) 8297–8300
2
NMR (162 MHz, CDCl3) l 323.4 (d, JPP 116 Hz), 34.4
(d, JPP 116 Hz).
p-CMe3), 34.1 (s, o-CMe3), 31.4 (s, p-CMe3), 21.5 (dd, 2JPC
17 Hz, JPC 3 Hz, Me). Anal. found: C, 53.63; H, 5.92%.
2
2
9. 4, 5: A THF (10 mL) solution of E-3 (100 mg, 0.205 mmol)
was mixed with a THF solution of W(CO)5(thf) (ca. 0.307
mmol, prepared from W(CO)6 by irradiation with a
medium-pressure Hg lamp (100 W) at 0°C in THF) at room
temperature for 3 days. The solvent was removed in vacuo
and the residue was purified by silica gel column chromato-
graphy (hexane/toluene 2:1) to afford 4: 116 mg, 70%;
31P{1H} NMR (162 MHz, CDCl3) l 331.6 (d, 2JPP 240 Hz),
26.5 (d, 2JPP 240 Hz, 1JPW (satellite) 246 Hz); 1H NMR (400
MHz, CDCl3) l 7.61–7.38 (12H, m, arom), 1.40 (18H, s,
o-t-Bu), 1.32 (9H, s, p-t-Bu), 1.27 (3H, dd, 3JPH 13 Hz, 3JPH
10 Hz, Me). Complex 4 (116 mg, 0.144 mmol) in THF was
irradiated with a medium-pressure Hg lamp (100 W) at 0°C
for 70 h to afford 5 after silica gel column chromatography
(hexane/toluene 3:1), 33 mg, 29% yield. 5: Orange crystals,
mp 246°C (decomp); 31P{1H} NMR (162 MHz, CDCl3) l
247.7 (d, 2JPP 115 Hz, 1JPW (satellite) 205 Hz), 3.1 (d, 2JPP
Calcd for C32H42Cl2P2Pd·0.9CH2Cl2: C, 53.22, H, 5.96%.
12. 8: Mp 115°C (decomp, recrystalized from dichloro-
methane); 31P{1H} NMR (162 MHz, CDCl3) l 35.8 (d, 2JPP
45 Hz), −32.9 (d, 2JPP 45 Hz); 1H NMR (400 MHz, CDCl3)
2
3
l 8.13 (2H, dd, JPH 13 Hz, JHH 7 Hz, o-Ph), 7.97 (2H,
dd, 2JPH 13 Hz, 3JHH 7 Hz, o-Ph), 7.66–7.43 (8H, m, arom),
5.15 (1H, m, CH), 1.75 (9H, s, o-t-Bu), 1.65 (3H, dd, 3JPH
3
34 Hz, JPH 16 Hz, Me), 1.47 (9H, s, o-t-Bu), 1.33 (9H,
s, p-t-Bu), (OH could not be assigned). Anal. Found: C,
54.48; H, 6.22%. Calcd for C32H44Cl2OP2Pd·0.5CH2Cl2: C,
53.73; H, 6.26%.
13. X-ray
crystallography
for
8·CH2Cl2·H2O:
C33H46Cl4O2P2Pd·CH2Cl2·H2O,
M=786.90,
crystal
dimensions 0.30×0.30×0.25 mm3, monoclinic, space group
P21/c (no. 14), a=16.609(1), b=13.7163(8), c=17.9531(9)
3
,
,
A, i=114.692(2)°, V=3716.1(4) A , Z=4, T=120 K,
2qmax=55.0°, z=1.406 g cm–1, v(MoKa)=0.900 mm–1,
000=1624.00, 26852 measured reflections, 8192 unique
1
115 Hz, JPW (satellite) 200 Hz); 1H NMR (400 MHz,
F
reflections (Rint=0.041), R1=0.057 (I>2.0s(I)), Rw=
0.084 (all data) (CCDC-208864).
14. Araujo, M. H.; Hitchcock, P. B.; Nixon, J. F.; Keuhner,
CDCl3) l=7.55–7.50 (4H, m, arom), 7.46–7.42 (8H, m,
arom), 1.64 (18H, s, o-t-Bu), 1.43 (3H, dd, 3JPH 28 Hz, 3JPH
11 Hz, Me), 1.36 (9H, s, p-t-Bu); 13C{1H} NMR (101 MHz,
CDCl3) l 210.4 (dd, 2JPC 55 Hz, 2JPC 12 Hz, COeq), 209.8
(dd, 2JPC 38 Hz, 2JPC 14 Hz, COeq), 204.8 (dd, 2JPC 16 Hz,
U.; Stelzer, O. Chem. Commun. 2003, 1092.
15. Hollatz, C.; Schier A.; Schmidbaur, H. J. Am. Chem. Soc.
1997, 119, 8115. See also Li, G. Y. Angew. Chem., Int. Ed.
2001, 40, 1513.
16. Alternatively, the Wacker type oxidation process appeared
to be included, although detailed study for it has not been
performed so far.
1
1
2JPC 11 Hz, COax), 186.5 (dd, JPC 45 Hz, JPC 31 Hz,
P=C), 155.9 (s, o-Mes*), 153.3 (s, p-Mes*), 133.3 (dd, 1JPC
56 Hz, 3JPC 29 Hz, ipso-Mes*), 132.9 (d, 2JPC 21 Hz, o-Ph),
4
3
130.8 (d, JPC 3 Hz, p-Ph), 129.1 (d, JPC 16 Hz, m-Ph),
128.5 (pt, (1JPC+3JPC)/2 53 Hz, ipso-Ph), 122.6 (d, JPC
8
3
17. The lifetime of 8 prolonged by using chloroform which was
passed through basic alumina just before use.
18. 9: Mp 150°C (decomp); 31P{1H} NMR (162 MHz, CDCl3)
Hz, m-Mes*), 38.8 (s, o-CMe3), 35.6 (s, p-CMe3), 33.8 (d,
2
4JPC 4 Hz, o-CMe3), 31.5 (s, p-CMe3), 24.2 (dd, JPC 24
2
Hz, JPC 5 Hz, Me); IR (KBr) w 2013, 1899, 1876 cm−1
.
2
1
l 16.7 (d, JPP 52 Hz, JPPt (satellite) 3407 Hz), −40.4 (d,
2JPP 52 Hz, 1JPPt (satellite) 3447 Hz); 1H NMR (400 MHz,
CDCl3) l 8.11 (2H, m, Ph), 7.97 (2H, m, Ph), 7.61–7.37
(8H, m, arom), 5.20 (1H, m, CH), 1.72 (9H, s, o-t-Bu), 1.64
Anal. Found: C, 54.68; H, 5.21%. Calcd for C36H42P2O4W:
C, 55.11; H, 5.39%. Complex 5 was obtained from the
reaction of E-3 and W(CO)5(thf) in 3% yield.
10. X-ray crystallography for 5: C36H42O4P2W, M=784.52,
3
3
crystal dimensions 0.15×0.10×0.10 mm3, orthorhombic,
(3H, dd, JPH 8 Hz, JPH 3 Hz, Me), 1.45 (9H, s, o-t-Bu),
1.32 (9H, s, p-t-Bu) (OH could not be assigned); 13C{1H}
NMR (101 MHz, CDCl3) l 160.1 (m, o-Mes*), 154.3 (d,
space group P212121 (no. 19), a=16.791(1), b=22.0884(9),
3
,
,
c=9.3064(4) A, V=3451.6(3) A , Z=4, T=153 K,
2
4JPC 4 Hz, p-Mes*), 152.8 (m, o-Mes*), 137.3 (d, JPC 11
2qmax=55.0°, z=1.510 g cm−1, v(MoKa)=3.479 mm−1
000=1576.00, 24205 measured reflections, 4270 unique
,
1
Hz, o-Ph), 132.9 (d, JPC 41 Hz, ipso-Ph), 132.6 (s, p-Ph),
F
1
3
132.0 (s, m-Ph), 129.5 (dd, JPC 40 Hz, JPC 12 Hz,
reflections (Rint=0.068), R1=0.050 (I>2.0|(I)), Rw=
0.057 (all data) (CCDC-208866).
3
ipso-Mes*), 124.8 (d, JPC 3 Hz, m-Mes*), 124.7 (s,
1
1
m-Mes*), 40.3 (dd, JPC 82 Hz, JPC 3 Hz, PCP), 35.5 (s,
o-CMe3), 35.1 (s, p-CMe3), 33.2 (s, o-CMe3), 31.2 (s,
p-CMe3), 26.0 (m, Me). Anal. Found: C, 47.59; H, 5.87%.
Calcd for C32H44Cl2OP2Pt·2H2O: C, 47.53; H, 5.98%.
11. 6: A solution of a mixture of E-3 (100 mg, 0.205 mmol)
and PdCl2(MeCN)2 (0.205 mmol) in dichloromethane (5
mL) was stirred for 12 h. The reaction mixture was diluted
with hexane (10 mL) to generate yellow precipitates of 6.
The precipitates were filtered and washed with hexane to
afford 6: 133 mg, 88% yield. Mp 220°C (decomp); 31P{1H}
NMR (162 MHz, CDCl3) l 224.3 (d, 2JPP 52 Hz), −9.2 (d,
2JPP 52 Hz); 1H NMR (400 MHz, CDCl3) l 7.96–7.90 (4H,
m, arom), 7.68–7.64 (2H, m, arom), 7.58–7.54 (6H, m,
arom), 1.70 (18H, s, o-t-Bu), 1.69 (3H, dd, 3JPH 34 Hz, 3JPH
16 Hz, Me), 1.35 (9H, s, p-t-Bu); 13C{1H} NMR (101 MHz,
CDCl3) l 177.1 (dd, 1JPC 27 Hz, 1JPC 24 Hz, P=C), 157.6
(d, 2JPC 3 Hz, o-Mes*), 156.5 (d, 4JPC 2 Hz, p-Mes*), 134.0
(d, 2JPC 11 Hz, o-Ph), 133.4 (d, 4JPC 3 Hz, p-Ph), 129.1 (d,
19. X-ray
crystallography
for
9·C2H5OH·C4H8O,
C38H58Cl2O3P2Pt, M=890.82, crystal dimensions 0.20×
0.17×0.10 mm3, orthorhombic, space group P212121 (no.
,
19), a=17.2751(6), b=17.2986(7), c=14.1019(8) A, V=
3
,
4214.1(3) A , Z=4, T=296 K, 2qmax=55.0°, z=1.404 g
cm−1, v(MoKa)=3.550 mm−1, F000=1808.00, 32774 mea-
sured reflections, 5208 unique reflections (Rint=0.099),
R1=0.045 (I>3.0s(I)), Rw=0.062 (all data) (CCDC-
208865).
20. (a) Tykwinski, R. R. Angew. Chem., Int. Ed. 2003, 42, 1566;
(b) Negishi, E.; Anastasia, L. Chem. Rev. 2003, 103, 1979.
21. Siemsen, P.; Livingston, R. C.; Diederich, F. Angew.
Chem., Int. Ed. 2000, 39, 2632.
1
3
3JPC 13 Hz, m-Ph), 125.8 (dd, JPC 54 Hz, JPC 7 Hz,
ipso-Mes*), 123.9 (d, 3JPC 9 Hz, m-Mes*), 118.4 (dd, 1JPC
30 Hz, JPC 10 Hz, ipso-Ph), 38.7 (s, o-CMe3), 35.9 (s,
3