Addition of methanol to nonactivated internal alkynes catalyzed by dichloro(diphosphine)platinum(II) complex/silver salt systems

Article abstract of DOI:10.1021/om9605037

Nucleophilic addition of methanol to nonactivated alkynes is catalyzed by platinum phosphine complexes derived from PtCl₂(ligand) [ligand = 2PPh₃, 2PPh₂Me, diphos, dppt (1,5-bis(diphenylphosphino)-pentane)] and a silver salt [AgPF₆ or AgOTf (silver trifluoromethanesulfonate)] producing ketones in high yields. The catalytic activity is influenced by the phosphine ligand as well as by the anion and the ratio of the dichloroplatinum complex to the silver salt.

Full text of DOI:10.1021/om9605037

5246
Organometallics 1996, 15, 5246-5249
Ad d ition of Meth a n ol to Non a ctiva ted In ter n a l Alk yn es
Ca ta lyzed by Dich lor o(d ip h osp h in e)p la tin u m (II)
Com p lex/Silver Sa lt System s
Yasutaka Kataoka, Osamu Matsumoto, and Kazuhide Tani*
Department of Chemistry, Faculty of Engineering Science, Osaka University, Toyonaka,
Osaka 560, J apan
Received J une 21, 1996X
Summary: Nucleophilic addition of methanol to nonac-
tivated alkynes is catalyzed by platinum phosphine
complexes derived from PtCl2(ligand) [ligand ) 2PPh3,
2PPh2Me, diphos, dppt (1,5-bis(diphenylphosphino)-
pentane)] and a silver salt [AgPF6 or AgOTf (silver
trifluoromethanesulfonate)] producing ketones in high
yields. The catalytic activity is influenced by the phos-
phine ligand as well as by the anion and the ratio of the
dichloroplatinum complex to the silver salt.
dicarboxylate).10 However during the course of our
recent studies of the catalytic reaction, it was found that
the real activity of the dicationic platinum complexes
is obscured because a silver salt such as AgPF6 by itself
also showed catalytic activity in the addition of metha-
nol to DMAD.11 These observations prompted us to
reexamine the catalyzed addition of methanol to alkynes
by these platinum complexes using nonactivated alkynes
to which methanol was not able to add in the presence
only of silver salts. We describe here that several
platinum complex systems derived from PtCl2(ligand)
[ligand ) 2PPh3, 2PPh2Me, diphos, dppt (1,5-bis(diphe-
nylphosphino)pentane)] and a silver salt [AgPF6 or
AgOTf (silver trifluoromethanesulfonate)] catalyze the
addition of methanol to nonactivated alkynes and that
the catalytic activity is influenced by the phosphine
ligand as well as by the anion and the ratio of PtCl2-
(ligand) to the silver salt.
In tr od u ction
Intermolecular addition of an alcohol to alkynes is one
of the efficient routes for functionalization of a C-C
triple bond.1 Although it has been reported that inter-
molecular addition of alcohol to activated alkynes hav-
ing electron-withdrawing groups such as an ester group
is catalyzed by bases,2 copper(I) triflate,3 mercury(II)
chloride/triethylamine,4 palladium(II) complexes,5 or a
cuboidal PdMoS4 cluster,6 there have been only two
reports on the intermolecular addition of an alcohol to
nonactivated internal alkynes which have no electron-
withdrawing substituents.7
The study of cationic palladium complexes has at-
tracted much attention due to both enhancement of
electrophilicity8 and supply of vacant sites9 on the metal
center. Recently we have reported that dicationic
platinum complexes prepared from PtCl2(phosphine)
(phosphine ) 2PPh3, diphosphine) and excess AgPF6
catalyze the addition of an alcohol to several alkynes.
Especially high catalytic activity is observed with
activated alkyne such as DMAD (dimethyl acetylene-
Resu lts a n d Discu ssion
X Abstract published in Advance ACS Abstracts, November 1, 1996.
(1) Larock, R. C.; Leong, W. W. Comprehensive Organic Synthesis;
Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, U.K., 1991;
Vol. 4, p 269.
(2) (a) Winterfeldt, E. Chem. Ber. 1964, 97, 1952. (b) Winterfeldt,
E.; Preuss, H. Chem. Ber. 1966, 99, 450. (c) Walia, J . S.; Walia, A. S.
J . Org. Chem. 1976, 41, 3765. (d) Ireland, R. E.; Wipf, P.; Xiang, J .-N.
J . Org. Chem. 1991, 56, 3572. (e) Inanaga, J .; Baba, Y. ; Hanamoto, T.
Chem. Lett. 1993, 241.
(3) Bertz, S. H.; Dabbagh, G.; Cotte, P. J . Org. Chem. 1982, 47, 2216.
(4) Barluenga, J .; Aznar, F.; Bayod, M. Synthesis 1988, 144.
(5) Avshu, A.; O’Sullivan, R. D.; Parkins, A. W.; Alcock, N. W.;
Countryman, R. M. J . Chem. Soc., Dalton Trans. 1983, 1619.
(6) Murata, T.; Mizobe, Y.; Gao, H.; Ishii, Y.; Wakabayashi, T,;
Nakano, F.; Tanase, T.; Yano, S.; Hidai, M.; Echizen, I.; Nanikawa,
H.; Motomura, S. J . Am. Chem. Soc. 1994, 116, 3389.
(7) (a) Hiscox, W.; J ennings, P. W. Organometallics 1990, 9, 1997.
(b) Fukuda, Y.; Utimoto, K. J . Org. Chem. 1991, 56, 3729.
(8) Karabelas, K.; Westerlund, C.; Hallberg, A. J . Org. Chem. 1985,
50, 3896.
The results of the addition of MeOH to dodec-6-yne
catalyzed by several platinum species are summarized
in Table 1. A mixture of dodec-6-yne (0.5 mmol) and
MeOH (0.5 mL, 13 mmol) in CH2Cl2 (0.5 mL) was stirred
at 22 °C for 18 h in the presence of a catalytic amount
of the platinum species (10 mol %) prepared in situ from
PtCl2(diphos) (0.05 mmol) and AgOTf (0.05 mmol).
Dodecan-6-one, the hydrolyzed product of the vinyl ether
initially formed in the addition of MeOH to dodec-6-yne,
was obtained in 99% yield (Table 1, run 1). The 1H
NMR spectrum of the reaction mixture did not show any
sign of formation of the vinylic ether and showed only
the presence of the hydrolyzed products, the respective
ketones. The reaction system was so acidic that the
initial products, the vinylic ethers, might be easily
hydrolyzed under the reaction conditions. All platinum
species derived from PtCl2(diphos) and a silver salt
(9) (a) Dekker, G. P. C. M.; Elsevier, C. J .; Vrieze, K.; van Leeuwen,
P. W. N. M. Organometallics 1992, 11, 1598. (b) Dekker, G. P. C. M.;
Elsevier, C. J .; Vrieze, K.; van Leeuwen, P. W. N. M.; Roobeek, C. F.
J . Organomet. Chem. 1992, 430, 357. (c) Kayaki, Y.; Shimizu, I.;
Yamamoto, A. Chem. Lett. 1995, 1089. (d) Yamamoto, A. J . Organomet.
Chem. 1995, 500, 337. (e) Kawataka, F.; Shimizu, I.; Yamamoto A.
Bull. Chem. Soc. J pn. 1995, 68, 654. (f) Sodeoka, M.; Ohrai, K.;
Shibasaki, M. J . Org. Chem. 1995, 60, 2648.
(10) Kataoka, Y.; Matsumoto, O.; Ohashi, M.; Yamagata, T.; Tani,
K. Chem. Lett. 1994, 1283.
(11) Kataoka, Y.; Matsumoto, O.; Tani, K, Chem. Lett. 1996, 727.
S0276-7333(96)00503-1 CCC: $12.00 © 1996 American Chemical Society

Notes
Organometallics, Vol. 15, No. 24, 1996 5247
Ta ble 1. Rea ction of Dod ec-6-yn e w ith Meth a n ol
Ca ta lyzed by P t(II)-Ag System sa
be replaced by alkynes, prevented the formation of the
insoluble platinum oligomer complex.
dodecan-6-one yield/%b
In order to obtain further information about the
catalytically active species we have examined the 31P
NMR spectra of the catalyst systems. The 31P NMR
spectrum of the reaction mixture derived from cis-PtCl2-
(PPh3)2 and 1 equiv of AgOTf in a mixed solvent of
MeOH-d4 and CH2Cl2 (1:1) showed mainly two sets of
signals [δ 4.2 (d, J Pt-P ) 4019 Hz, J P-P ) 18 Hz), 19.4
run
catalyst system
1
2
3
4
5
6
7
8
PtCl2(diphos) - 1AgOTf
PtCl2(diphos) - 3AgOTf
PtCl2(diphos) - 1AgPF6
PtCl2(diphos) - 3AgPF6
PtCl2(PPh3)2 - 1AgOTf
PtCl2(PPh3)2 - 3AgOTf
PtCl2(PPh3)2 - 1AgPF6
PtCl2(PPh3)2 - 3AgPF6
99
83
89
79
95
3
6
18
(d, J Pt-P ) 3962 Hz, J P-P ) 18 Hz) and δ 9.2 (d, J Pt-P
)
3554 Hz, J P-P ) 18 Hz), 13.3 (d, J Pt-P ) 4108 Hz, J P-P
) 18 Hz)], probably due to cis-(Ph3P)2PtCl(OTf) and cis-
[(Ph3P)2PtCl(MeOH)](OTf) or vice versa. Although sev-
eral other singlet signals are present, the signal due to
aDodec-6-yne (5.0 mmol) was treated with a platinum complex
(0.5 mmol) and n silver salts (n ) 1, 0.5 mmol; n ) 3, 1.5 mmol)
b
in CH2Cl2 (0.5 mL) and MeOH (0.5 mL) at 22 °C for 18 h. Yield
was determined by GLC using a Shimazu capillary column, CBP1-
M25-025.
the starting dichloride PtCl2(PPh3)2 [δ 14.8 (s, J Pt-P
)
3700 Hz)] disappeared completely.
showed similarly high activity under these conditions
regardless of the anion and the amount of silver salt
employed (run 1-4). On the other hand, the catalytic
activity of the platinum species derived from cis-PtCl2-
(PPh3)2 varied considerably depending on the anion and
the amount of the silver salt. When cis-PtCl2(PPh3)2
and AgOTf were employed as a precursor of the plati-
num species, the catalyst system obtained by using 1
equiv of AgOTf showed high catalytic activity (run 5),
whereas an excess of AgOTf reduced the catalytic
activity drastically (run 6). When AgPF6 was employed
as the silver salt, low activities always were observed
regardless of the amount of the silver salt (runs 7, 8).
The catalytic system prepared from a diphosphine
complex, PtCl2(dppt) [dppt ) 1,5-bis(diphenylphosphi-
no)pentane], and silver salts showed activity similar to
that of the PtCl2(diphos) system; dodecan-6-one was
obtained in yields of 93% (with 1 equiv of AgOTf), 91%
(with 3 equiv of AgOTf), 75% (with 1 equiv of AgPF6),
and 90% (with 3 equiv of AgPF6). The activity of the
PtCl2(PPh2Me)2-silver salt system showed similar ten-
dency to that of PtCl2(PPh3)2 system; dodec-6-one was
obtained in yields of 97% (with 1 equiv of AgOTf), 32%
(with 3 equiv of AgOTf), 33% (with 1 equiv of AgPF6),
and 11% (with 3 equiv of AgPF6).
To explore the reason of the different reactivities
depending on the anion of the silver salts employed in
the cis-PtCl2(PPh3)2 systems, the following stoichiomet-
ric reactions were carried out. Reaction of cis-PtCl2-
(PPh3)2 with 1 equiv of AgPF6 in the presence of 3 equiv
of dodec-6-yne at 22 °C in CH2Cl2 and MeOH (1:1)
yielded a colorless precipitate. Elemental analysis of
the white solid obtained after removal of AgCl from the
precipitate suggested the formation of a chloride-bridged
oligomer complex, [(Ph3P)2PtCl]n(PF6)n (n > 1) (eq 2).
When cis-PtCl2(PPh3)2 was reacted with an excess of
silver salt, the chloride ligands can be removed com-
pletely judging from the disappearance of the Pt-Cl
stretch in the IR spectrum of the reaction product.13 The
31P NMR spectrum also supported the removal of the
chloride ligand. For example, the 31P NMR spectrum
of cis-PtCl2(PPh3)2-3AgOTf in MeOH-d4 and CH2Cl2 (1:
1) showed three signals at δ 4.8 (s, J Pt-P ) 4080 Hz),
8.2 (s, J Pt-P ) 3730 Hz), and 33.3 (s, J Pt-P ) 3014 Hz).
The first two signals could be assigned to cis-[Pt(PPh3)2-
(MeOH)2](OTf)2 and cis-Pt(PPh3)2(OTf)2 or vice versa
and the lowest field signal to trans-[Pt(PPh3)2(MeOH)2]
195
(OTf)2 according to the coupling constants between
-
Pt and 31P.14
The reason that the catalytic activity of cis-PtCl2-
(PPh3)2-3AgX (X ) PF6 or OTf) systems, despite the
soluble platinum species formed, was extremely low
compared to that of the PtCl2(diphos)-3AgX systems
is not clear at present. It could be due to the difference
of their geometry. The bidentate diphosphine ligand
(diphos) can only take cis configuration but triph-
enylphosphine can also take a trans configuration,
which may be the predominant but inactive species at
the key step of the catalytic process; reaction of DMAD
and MeOH with cis-PtCl2(PPh3)2 and 1 equiv of AgPF6
in CH2Cl2 gave trans-PtCl(PPh3)2{η1-(E)-CH3O2CCdC-
(OMe)CO2CH3} in 74% isolated yield (eq 3). Despite
careful NMR investigation of the reaction mixture, we
have not been able to obtain any positive information
about the real catalytic species, so far; we could not
observe an interaction of the alkyne with a platinum
species, etc.
Addition of MeOH to unsymmetrical alkynes produces
two regioisomeric ketones (eq 4). Both the size and
electronic properties of the substituents on the alkyne
influence the regioselectivity. For example, reaction of
The latter was not soluble in CH2Cl2 and therefore did
not show any catalytic activity. On the other hand, the
reaction of the cis-PtCl2(PPh3)2 with 1 equiv of AgOTf
precipitated only AgCl, leaving the active platinum
species in solution. These results indicate that a triflate
anion, which has a higher coordination ability12 but can
(13) ν(Pt-Cl): 346 cm-1 for PtCl2(diphos); 296 and 320 cm-1 for cis-
PtCl2(PPh3)2.
(14) (a) Pidcock, A.; Richards, R. E.; Venanzi, L. M. J . Chem. Soc. A
1966, 1707. (b) Pidcock, A. In Catalytic Aspects of Metal Phosphine
Complexes; Alyea, E. C., Meek, D. W., Eds.; American Chemical
Society: Washington, DC, 1982; pp 1-22.
(12) Beck, W.; Su¨nkel, K. Chem. Rev. 1988, 88, 1405 and references
cited therein.

5248 Organometallics, Vol. 15, No. 24, 1996
Notes
Gen er al P r ocedu r e for Addition of MeOH to an Alkyn e
Ca ta lyzed by th e System s Der ived fr om P tCl2(liga n d )
(Liga n d ) 2 Mon od en ta te P h osp h in es or a Dip h osp h in e)
a n d a Silver Sa lt (AgP F 6 or AgOTf). To a solution of a
platinum complex [PtCl2(ligand), 0.05 mmol] in a mixed
solvent of CH2Cl2 (0.5 mL) and MeOH (0.5 mL) at 22 °C was
added a silver salt (AgPF6 or AgOTf, 0.05 mmol or 0.15 mmol).
The reaction mixture was stirred for 15 min at 22 °C, and then
the alkyne (0.5 mmol) was added. After 18 h, the yield of the
ketone was determined by GLC or after isolation with column
chromatography.
Dod eca n -6-on e.19 The yield was determined by GLC. GLC
conditions: Simadzu capillary column, CBP1-M25-025; column
temperature, 130 °C; internal standard, tetradecane; retention
time, 5.0 min (dodec-6-yne), 7.3 min (dodecan-6-one), 9.5 min
(tetradecane).
1-Cycloh exyldodecan -1-on e (2a) an d 1-cycloh exyldode-
ca n -2-on e (3a ). The two compounds (2a :3a ) 26:74) could
not be separated with column chromatography. 1H NMR
(CDCl3): δ 0.80-1.04 {m, 3H (2a and 3a )}, 1.04-1.48 (m, 18H
(2a ) and 16H (3a )}, 1.42-1.68 {m, 4H (2a and 3a )}, 1.56-
1.96 {m, 6H (2a ) and 7H (3a )}, 2.26 {d, J ) 6.9 Hz, 2H (3a )},
2.36 {t, J ) 7.3 Hz, 2H (3a )}, 2.41 {t, J ) 7.2 Hz, 2H (2a )},
2.30-2.44 {m, 1H (2a )}. IR (neat): 2930, 2853, 1712, 1449,
1409, 1375, 1146, 721 cm-1. HRMS (EI): m/ z 266.2563 (M+).
Calcd for C18H34O 266.2610.
1-P h en yld od eca n -1-on e (2b).19 1H NMR (CDCl3): δ 0.88
(t, J ) 6.7 Hz, 3H), 1.2-1.5 (m, 16H), 1.74 (tt, J ) 7.4, 7.7 Hz,
2H), 2.96 (t, J ) 7.4 Hz, 2H), 7.4-7.6 (m, 3H), 7.9-8.0 (m,
2H).
1-P h en yld od eca n -2-on e (3b).20 1H NMR (CDCl3): δ 0.88
(t, J ) 6.7 Hz, 3H), 1.1-1.4 (m, 14H), 1.4-1.6 (m, 2H), 2.43 (t,
J ) 7.3 Hz, 2H), 3.67 (s, 2H), 7.1-7.4 (m, 5H).
1-cyclohexyldodec-1-yne (1a ) with MeOH in the presence
of PtCl2(diphos) and excess AgOTf in CH2Cl2 afforded
a mixture of two regioisomeric ketones (2a :3a ) 25:75)
in 89% isolated yield. The major isomer was produced
by addition of MeOH at the less hindered side of the
C-C triple bond. In contrast, addition of MeOH to
1-phenyldodec-1-yne took place at the more sterically
congested position R to the phenyl group.15 When a
terminal alkyne such as dodec-1-yne was employed in
this reaction, MeOH added at the sterically congested
site of the C-C triple bond to yield dodecan-2-one
selectively.
In conclusion, we have found that cationic platinum-
phosphine complexes or platinum-phosphine complexes
with anions of moderate coordination ability derived
from PtCl2(ligand) and silver salts catalyze the addition
of methanol to nonactivated alkynes affording the
corresponding ketone. The catalytic activity of the
platinum species depends upon the phosphorus ligand
of the starting platinum complex and on the anion.
Syn th esis of a Ch lor id e-Br id ged Oligom er Com p lex,
[(P h 3P )2P tCl]n (P F 6)n (n > 1). In a Schlenk flask was placed
cis-PtCl2(PPh3)2 (153 mg, 0.194 mmol) under an Ar atmo-
sphere. To the complex were added successively at 22 °C CH2-
Cl2 (2 mL), MeOH (2 mL), and dodec-6-yne (79 mg, 0.475
mmol). AgPF6 was added to the solution, and the mixture was
stirred at 22 °C for 20 min. The resulting colorless precipitate
was filtered and washed with CH2Cl2 (10 mL). To the
precipitate was added a mixed solvent of nitromethane and
acetonitrile (5 mL, 1:1). The insoluble, colorless solid was
removed by filtration, and the filtrate was concentrated
in vacuo. A white powder of [(Ph3P)2PtCl]n(PF6)n (n > 1)
was obtained after recrystallization from CH3CN-Et2O. Mp:
251.4-254.8 °C (dec). The complex is soluble in CH3CN and
Exp er im en ta l Section
All manipulations were conducted under argon atmosphere
with standard Schlenk methods. Unless otherwise noted,
materials were obtained from commercial suppliers and
were used after distillation. All solvents were distilled under
argon prior to use, CH2Cl2 from CaH, MeOH from Mg(OMe)2,
and CH3CN from CaH. PtCl2(diphos), cis-PtCl2(PPh3)2, cis-
PtCl2(PPh2Me)2, and PtCl2(dppt) (dppt ) Ph2P(CH2)5PPh2)
were prepared according to published procedures.16 1-Cyclo-
hexyldodec-1-yne (1a ) and 1-phenyldodec-1-yne (1b) were
prepared by similar methods to published procedures.17,18
Column chromatography was conducted by using silica gel 60
(E. Merck 9385 230-400 mesh). The melting points were
recorded on a Yanaco MP-52982 and are uncorrected. IR
spectra were determined on a Hitachi 295 spectrophotometer
or J ASCO FT/IR-230. Mass spectra were obtained on a J EOL
J MS DX-303HF spectrometer or PE-Sciex API-III plus. 1H
NMR spectra were recorded at 270.05 MHz on a J EOL GSX-
270 spectrometer, and 31P NMR spectra at 109.25 MHz on a
J EOL GSX-270 spectrometer. Chemical shifts of 1H NMR are
expressed in ppm downfield from Me4Si using the δ scale
(CHCl3 was used as an internal standard, δ 7.26), and those
of 31P NMR are referred to 85% H3PO4 as an external
reference. Elemental analysis was carried out with a Yanaco
MT-3.
shows 31P NMR signals in CD3CN at δ -143.1 (septet, J P-F
)
707 Hz, 2P, PF6), 6.0 (d, J Pt-P ) 3841 Hz, J P-P ) 18 Hz, 2P,
Ph3P), and 13.5 (d, J Pt-P ) 3503 Hz, J P-P ) 18 Hz, 2P, Ph3P),
due to a monomeric species, cis-[(PPh3)2PtCl(CH3CN)]+.21 1H
NMR (CD3CN): δ 7.15-7.60 (m, 60H, arom). IR (Nujol): 1550,
1440, 1315, 1100, 1000, 880, 855, 840, 760, 750, 710, 700, 560,
555, 535, 520, 505, 320 cm-1. MS (ESIMS, CH3CN solution):
m/ z 796 [PtCl(PPh3)2(CH3CN)], 753 [PtCl(PPh3)2], 718 [Pt-
(PPh3)2]. Anal. Calcd for (C36H30P3ClF6Pt)n: C, 48.04; H, 3.36.
Found: C, 48.18; H, 3.62.
tr a n s-P tCl(P P h 3)2{η1-(E)-CH3O2CCdC(OMe)CO2CH3}.
To a solution of cis-PtCl2(PPh3)2 (65 mg, 0.082 mmol) and
dimethyl acetylenedicarboxylate (DMAD) (36 mg, 0.25 mmol)
in a mixture of CH2Cl2 and MeOH (5 mL, 1:1) was added
AgPF6 (21 mg, 0.082 mmol). The reaction mixture was stirred
for 20 min at 20 °C, and then the precipitated AgCl was
removed by filtration. The yellow filtrate was concentrated
in vacuo. The residual yellow semisolid was washed with two
portions of ether (20 mL × 2) and then dried under reduced
(15) Similar regioselectivities were observed in the reaction of
tantalum-unsymmetrical acetylene complexes with carbonyl com-
pounds, see: (a) Takai, K.; Kataoka, Y.; Utimoto, K. J . Org. Chem.
1990, 55, 1707. (b) Kataoka, Y.; Miyai, J .; Tezuka, M.; Takai, K.;
Utimoto, K. J . Org. Chem. 1992, 57, 6796.
(16) Rahn, J . A.; Baltusis, L.; Nelson, J . H. Inorg. Chem. 1990, 29,
750.
(17) Corey, E. J .; Fuchs, P. L. Tetrahedron Lett. 1972, 3769.
(18) Kauffmann, T.; Rauch, E.; Schulz, J . Chem. Ber. 1973, 106,
1612.
(19) Handbook of Data on Common Organic Compounds; Lide, D.
R., Milne, G. W. A., Eds.; CRC Press: New York, 1994; Vol. III.
(20) Murata, Y.; Inomata, K.; Kinoshita, H.; Kotake, H. Bull. Chem.
Soc. J pn. 1983, 56, 2539.
(21) Davies, J . A.; Hartley, F. R.; Murray, S. G. Inorg. Chem. 1980,
19, 2299.

Notes
Organometallics, Vol. 15, No. 24, 1996 5249
pressure to give the pure alkenylplatinum complex as a yellow
powder (57 mg, 0.061 mmol) in 74% yield. Mp: 255.2-257.8
°C (dec). 1H NMR (CDCl3): δ 2.67 (s, 3H), 3.24 (s, 3H), 3.45
(s, 3H), 7.31-7.48 (m, 18H), 7.70-7.84 (m, 12H). 31P NMR
(CDCl3): δ 22.2 (s, J Pt-P ) 2949 Hz). MS (FAB): m/ z 929,
928, 987 (M+). IR (Nujol): 1710, 1705, 1440, 1300, 1200, 1120,
cis-P tCl2(P P h 3)2-3AgOTf: δ 4.8 (s, J Pt-P ) 4080 Hz), 8.2
(s, J Pt-P ) 3730 Hz), and 33.3 (s, J Pt-P ) 3014 Hz).
P tCl2(d ip h os): δ 43.4 (s, J Pt-P ) 3638 Hz).
P tCl2(d ip h os)-1AgOTf: 14.9 (d, J Pt-P ) 2361 Hz, J P-P
)
16 Hz), 18.4 (d, J Pt-P ) 2274 Hz, J P-P ) 16 Hz), 36.5 (m, J Pt-P
) 3947 Hz), 46.4 (m, J Pt-P ) 3578 Hz), 49.8 (s, J Pt-P ) 2315
Hz), 52.5 (s, J Pt-P ) 2367 Hz), 56.0 (s, J Pt-P ) 3016 Hz).
P tCl2(d ip h os)-3AgOTf: 35.9 (s, J Pt-P ) 3620 Hz), 39.0
(s, J Pt-P ) 3935 Hz).
1100, 1050, 1020, 750, 710, 525, 505, and 340 cm-1
. Anal.
Calcd for C43H39ClP2O5Pt: C, 55.64; H, 4.23. Found: C, 55.39;
H, 4.42.
31P NMR Exp er im en t [in a Mixed Solven t of MeOH-d 4
a n d CH2Cl2 (1:1)]. cis-P tCl2(P P h 3)2: δ 14.8 (s, J Pt-P ) 3700
Hz).
Ack n ow led gm en t. This work was supported by a
Grant-in-Aid for Scientific Research from the Ministry
of Education, Science, Sports, and Culture of J apan.
cis-P tCl2(P P h 3)2-1AgOTf: δ 4.2 (d, J Pt-P ) 4019 Hz, J P-P
) 18 Hz), 4.9 (s, J Pt-P ) 4080 Hz), 8.2 (s, J Pt-P ) 3730 Hz), 9.2
(d, J Pt-P ) 3554 Hz, J P-P ) 18 Hz), 13.3 (d, J Pt-P ) 4108 Hz,
J P-P ) 18 Hz), 15.7 (s, J Pt-P ) 3843 Hz), 19.4 (d, J Pt-P ) 3962
Hz, J P-P ) 18 Hz), and 33.3 (s, J Pt-P ) 3016 Hz).
OM9605037