Cooperative diastereoselectivity of palladium- and platinum-promoted intramolecular [4+2] Diels-Alder cycloaddition reactions of 3,4-dimethyl-1-phenylphosphole

Article abstract of DOI:10.1021/ic990885j

The complexes [(DMPP)₂M(CH₃CN)₂]X₂ (DMPP = 3,4-dimethyl-1-phenylphosphole; M = Pd, Pt; X = BF₄^-, NO₃^-, ClO₄^-) react with 2 equiv of the dienophiles N,N-dimethylacrylamide (DMAA), 2-vinylpyridine (VyPy), and diphenylvinylphosphine (DPVP) to form bis-[4+2] Diels-Alder cycloaddition products. The [M(DMPP)₂(DMAA)₂]²⁺ and [M(DMPP)₂(VyPy)₂]²⁺ complexes form exclusively as the cis-geometric isomers, whereas for [M(DMPP)₂(DPVP)₂]²⁺, both cis- and trans-geometric isomers are formed. The two Diels-Alder cycloadditions occur sequentially, and the absolute configuration of the first reaction influences the absolute configuration of the second. In all cases, racemic mixtures of the (R,R) and (S,S) diastereomers are formed; none of the meso (R,S) diastereomer is observed. New complexes were characterized by elemental analyses, physical properties, infrared spectroscopy, ¹H, ¹H{³¹P}, ¹³C{¹H}, and ³¹P{¹H} NMR spectroscopy, and, in most cases, X-ray crystallography.

Full text of DOI:10.1021/ic990885j

3392
Inorg. Chem. 2000, 39, 3392-3402
Cooperative Diastereoselectivity of Palladium- and Platinum-Promoted Intramolecular
[4+2] Diels-Alder Cycloaddition Reactions of 3,4-Dimethyl-1-phenylphosphole
Kent D. Redwine, William L. Wilson, Donald G. Moses, Vincent J. Catalano, and
John H. Nelson*
Department of Chemistry/216, University of NevadasReno, Reno, Nevada 89557-0020
ReceiVed July 26, 1999
-
The complexes [(DMPP)2M(CH3CN)2]X2 (DMPP ) 3,4-dimethyl-1-phenylphosphole; M ) Pd, Pt; X ) BF4
,
NO3-, ClO4-) react with 2 equiv of the dienophiles N,N-dimethylacrylamide (DMAA), 2-vinylpyridine (VyPy),
and diphenylvinylphosphine (DPVP) to form bis-[4+2] Diels-Alder cycloaddition products. The [M(DMPP)2-
(DMAA)2]2+ and [M(DMPP)2(VyPy)2]2+ complexes form exclusively as the cis-geometric isomers, whereas for
[M(DMPP)2(DPVP)2]2+, both cis- and trans-geometric isomers are formed. The two Diels-Alder cycloadditions
occur sequentially, and the absolute configuration of the first reaction influences the absolute configuration of the
second. In all cases, racemic mixtures of the (R,R) and (S,S) diastereomers are formed; none of the meso (R,S)
diastereomer is observed. New complexes were characterized by elemental analyses, physical properties, infrared
spectroscopy, 1H, 1H{31P}, 13C{1H}, and 31P{1H} NMR spectroscopy, and, in most cases, X-ray crystallography.
Introduction
Reactions 1-3 only occur with vinyl- or allylphosphines as
dienophiles, and in each case, racemic products are formed.
We have employed the highly efficient, diastereoselective
transition metal promoted intramolecular [4+2] Diels-Alder
cycloaddition reactions of 1H-phospholes1-7 and 2H-phos-
pholes8 with a variety of dienophilic ligands to form a number
of conformationally rigid asymmetric chelating ligands. The
scope and diastereoselectivity of these reactions depend on the
nature of the metal and its ancillary ligands as illustrated in
reactions 1-3.
Recently, organopalladium complexes containing optically
pure forms of orthopalladated [1-(dimethylamino)ethyl]naphtha-
lene9-17 and [2-(dimethylamino)ethyl]naphthalene18 were used
as chiral templates to promote asymmetric modifications of
several of these reactions. An example is shown in reaction 4.
(2) Solujic´, Lj.; Milosavljevic´, E. B.; Nelson, J. H.; Alcock, N. W.; Fischer,
J. Inorg. Chem. 1989, 28, 3453.
(3) Affandi, S.; Nelson, J. H.; Fischer, J. Inorg. Chem. 1989, 28, 4536.
(4) Bhaduri, D.; Nelson, J. H.; Day, C. L.; Jacobson, R. A.; Solujic´, Lj.;
Milosavljevic´, E. B. Organometallics 1992, 11, 4069.
(5) Ji, H.-L.; Nelson, J. H.; DeCian, A.; Fischer, J.; Solujic´, Lj.;
Milosavljevic´, E. B. Organometallics 1992, 11, 1840.
(6) Nelson, J. H. In Phosphorus-31 NMR Spectral Properties in Compound
Characterization and Structural Analysis; Quin, L. D., Verkade, J.
G., Eds.; VCH: Deerfield Beach, FL, 1994; pp 203-214.
(7) Redwine, K. D.; Catalano, V. J.; Nelson, J. H. Synth. React. Inorg.
Met.-Org. Chem. 1999, 29, 395.
(8) Maitra, K.; Catalano, V. J.; Nelson, J. H. J. Am. Chem. Soc. 1997,
119, 12560.
(9) Leung, P.-H.; Loh, S. H.; Mok, K. F.; White, A. J. P.; Williams, D.
J. J. Chem. Soc., Chem. Commun. 1996, 591.
(10) Aw, B. H.; Leung, P.-H.; White, A. J. P.; Williams, D. J. Organo-
metallics 1996, 15, 3640.
(11) Selvaratnam, S.; Mok, K. F.; Leung, P.-H.; White, A. J. P.; Williams,
D. J. Inorg. Chem. 1996, 35, 4798.
(12) Leung, P.-H.; Loh, S. K.; Mok, K. F.; White, A. J. P.; Williams, D.
J. J. Chem. Soc., Dalton Trans. 1996, 4443.
(1) Rahn, J. A.; Holt, M. S.; Gray, G. A.; Alcock, N. W.; Nelson, J. H.
Inorg. Chem. 1989, 28, 217.
10.1021/ic990885j CCC: $19.00 © 2000 American Chemical Society
Published on Web 06/24/2000

Cycloaddition Reactions of Dimethylphenylphosphole
Inorganic Chemistry, Vol. 39, No. 15, 2000 3393
Table 1. 1H and 31P{1H} NMR Data for [(DMPP)2M(NO3)2] (1a,b)
δ(1H)
2
M
solvent
temp (°C)
δ(31P) (1J(PtP))
Ph
HR (| J(PH) + 4J(PH)|)
CH3CN
CH3
Pd
Pd
Pt
Pt
Pt
CD3NO2
CD3CN
CD3NO2
CD3CN
CD3CN
25
25
25
25
75
37.6
39.3
7.20-7.45 (m)
7.42-7.66 (m)
7.40-7.70 (m)
7.38-7.70 (m)
6.41 (34.5 Hz)
6.42 (35.5 Hz)
6.34 (33.5 Hz)
6.35 (33.5 Hz)
2.07
2.16
2.08
2.12
2.01
2.03
7.96 (3663 Hz)
{17.02 (3159 Hz)a 11.63 (3472 Hz)a}
{10.42 (3667 Hz)b 9.93 (3652 Hz)b}
a cis-[(DMPP)2Pt(CD3CN)(NO3)]+. b cis-[(DMPP)2Pt(CD3CN)2]2+
.
Table 2. Crystallographic Data for [(DMPP)2Pd(NO3)2] (1a) and
[(DMPP)2Pt(NO3)2] (1b)
Disolvento bis(phosphine) complexes of palladium(II)19 and
platinum(II)20 of the type [(R3P)2M(S)2]2+ (S ) solvent) are
readily prepared by reactions of [(R3P)2MCl2] complexes with
a silver salt of a weakly coordinating anion in a donor solvent.
We reasoned that similar reactions of [(DMPP)2PdCl2]21,22 and
[(DMPP)2PtCl2]23,24 (DMPP ) 3,4-dimethyl-1-phenylphosphole)
with AgBF4, AgNO3, or AgClO4 in CH3CN followed by
addition of 2 equiv of a dienophilic ligand such as N,N-
dimethylacrylamide (DMAA), 2-vinylpyridine (VyPy), or di-
phenylvinylphosphine (DPVP) might lead to two sequential
metal-promoted intramolecular [4+2] Diels-Alder cycloaddi-
tions. Complementarity25 in the fitting of the two conforma-
tionally rigid chiral asymmetric bidentate ligands around the
metal center could then provide for asymmetric induction and
the preferential formation of homochiral (R,R) and (S,S)
diastereomers rather than the formation of the internally
compensated meso (R,S) diastereomers. The diastereoselectivi-
ties of these reactions are described herein.
1a
1b
empirical formula
fw
C24H26N2O6P2Pd
606.81
C24H26N2O6P2Pt
695.50
crystal system
space group
Z
a (Å)
b (Å)
orthorhombic
Pbca
8
18.462(2)
13.719(2)
20.356(2)
5156.0(9)
1.563
25
8.85
0.0394
0.0968
orthorhombic
Pbca
8
18.537(2)
13.7270(9)
20.392(2)
5189.0(9)
1.781
25
55.73
0.0529
0.0857
c (Å)
V (Å3)
F
calc (g cm-3
)
T (°C)
µ (cm-1
)
R1(F)a [I > 2σ(I)]
wR2(F2)b
GOF
1.021
1.001
a R1(F) ) ∑||F0| - |Fc||/∑|F0|. b wR2(F2) ) {∑[w(F0 - Fc2)2]/
2
∑[w(F0 )]2}0.5
.
2
5), as evidenced by the 1H and 31P{1H} NMR spectra recorded
Results and Discussion
in CD3NO2 and CD3CN (Table 1). The populations of the
Synthesis and Characterization of [(DMPP)2M(NO3)2].
The chloro complexes [(DMPP)2MCl2] (M ) Pd,21,22 Pt23,24
)
react cleanly with 2 equiv of AgNO3 in CH3CN solution at
ambient temperature to form AgCl and pale yellow and colorless
crystals of cis-[(DMPP)2Pd(NO3)2] (1a) and cis-[(DMPP)2Pt-
(NO3)2] (1b), respectively. Infrared spectra of their Nujol mulls
exhibit νNO vibrations at 1480, 1440, 1282, 1262, 1004, and
786 cm-1 (1a) and 1493, 1456, 1281, 1261, 989, and 789 cm-1
(1b), similar to the data reported26 for [(Ph3P)2Pt(NO3)2]. In CD3-
CN solutions, these complexes are in equilibrium with the
solvento species cis-[(DMPP)2Pd(CD3CN)2]2+, cis-[(DMPP)2Pt-
(CD3CN)(NO3)]+, and cis-[(DMPP)2Pt(CD3CN)2]2+ (reaction
solvento species increase with increasing temperature, suggest-
ing that nitrate is a better donor to palladium(II) and platinum(II)
than CD3CN.
Crystallization from an CH3CN/ether mixture provided X-ray-
quality crystals. Crystallographic data are listed in Table 2.
Views of the structures of 1a and 1b are shown in Figures 1
and 2. These two compounds are isomorphous and isostructural.
They both possess cis geometries. Even though they contain
coordinated CH3CN in CH3CN solutions, from which the
crystals were isolated, they do not contain coordinated CH3CN
in the solid state, consistent with equilibrium 5 lying to the left.
They are rigorously planar, as the sums of the angles around
the metals are 360.1(1)° in both cases. They contain monoden-
tate nitrate ions, as suggested by infrared spectroscopy.27 The
M-P distances are essentially the same (2.2455 Å, average,
Pd; 2.226 Å, average, Pt) as are the M-O distances (2.111 Å,
average, Pd; 2.092 Å, average, Pt). The latter are comparable
to the Pd-O distances (2.066 Å) reported28 for cis-[(Me2-
SO)2Pd(NO3)2]. The Pd-P distances are similar to those in cis-
[(DMPP)2PdCl2] (2.291 Å, average).21
(13) Aw, B. H.; Hor, T. S. A.; Selvaratnam, S.; White, A. J. P.; Williams,
D. J.; Rees, N. H.; McFarlane, W.; Leung, P.-H. Inorg. Chem. 1997,
36, 2138.
(14) Leung, P.-H.; Selvaratnam, S.; Cheng, C. R.; Mok, K. F.; Rees, N.
H.; McFarlane, W. J. Chem. Soc., Chem. Commun. 1997, 751.
(15) Liu, A. M.; Mok, K. F.; Leung, P.-H. J. Chem. Soc., Chem. Commun.
1997, 2397.
(16) Leung, P.-H.; Siah, S. Y.; White, A. J. P.; Williams, D. J. J. Chem.
Soc., Dalton Trans. 1998, 893.
(17) Song, Y.; Vittal, J. J.; Chan, S.-H.; Leung, P.-H. Organometallics 1999,
18, 650.
(18) Gu¨l, N.; Nelson, J. H. Tetrahedron 2000, 56, 71.
(19) Hartley, F. R.; Murray. S. G.; Wilkinson, A. Inorg. Chem. 1989, 28,
549 and references therein.
(20) Siegmann, K.; Pregosin, P. S.; Venanzi, L. M. Organometallics 1989,
8, 2659.
(21) MacDougall, J. J.; Cary, L. W.; Mayerle, J.; Mathey, F.; Nelson, J.
H. Inorg. Chem. 1980, 19, 709.
(22) Wilson, W. L.; Fischer, J.; Wasylishen, R. E.; Eichele, K.; Catalano,
V. J.; Frederick, J. H.; Nelson, J. H. Inorg. Chem. 1996, 35, 1486.
(23) MacDougall, J. J.; Nelson, J. H.; Mathey, F. Inorg. Chem. 1982, 21,
2145.
Reactions of [(DMPP)2M(CH3CN)2]X2 with the Dieno-
philic Ligands DMAA, VyPy, and DPVP. After addition of
2 equiv of AgX (X ) BF4-, NO3-, ClO4-) to a solution of 1
(24) Wilson, W. L.; Rahn, J. A.; Alcock, N. W.; Fischer, J.; Frederick, J.
H.; Nelson, J. H. Inorg. Chem. 1994, 33, 109.
(25) Bray, K. L.; Butts, C. P.; Lloyd-Jones, G. C.; Murray, M. J. Chem.
Soc., Dalton Trans. 1998, 1421.
(27) Nakamoto, K. Infrared and Raman Spectra of Inorganic and Coor-
dination compounds, 5th ed.; Wiley-Interscience: New York, 1997;
Parts A and B.
(28) Langs, D. A.; Hare, C. R.; Little, R. G. J. Chem. Soc., Chem. Commun.
1967, 1080.
(26) Cook, C. D.; Jauhal, G. S. J. Am. Chem. Soc. 1967, 89, 3066.

3394 Inorganic Chemistry, Vol. 39, No. 15, 2000
Redwine et al.
generally easier to isolate and crystallize. Consequently, most
-
of the complexes were fully characterized only as their BF4
salts.
Because the [4+2] Diels-Alder cycloaddition reactions all
occur intramolecularly1-17 within the coordination sphere of the
metal to form the syn-exo-7-phosphanorbornene skeleton (il-
lustrated as follows), the absolute configurations of the C(1)
and C(4) stereocenters are fixed and only those at C(2) (the
ring conjunction carbon) and P(7) may vary. In both of the
enantiomers of these ligands, the stereochemistry of C(2) is the
same as that of P(7). Thus, we will refer to the absolute
configuration of these chiral ligands by a single descriptor, R
or S.
Compounds 2-6 (Scheme 1) could form as either cis- or
trans-geometric isomers, or as both. For 2, 5, and 6, only the
cis isomers are formed, whereas for the dienophile DPVP, both
the cis isomers (3) and the trans isomers (4) are formed. The
nature of the geometric isomers that are formed in these
reactions may be rationalized by considering both the minimiza-
tion of interligand steric interactions and the differential trans
influence30 of the donor atoms.
Figure 1. Structural drawing of [(DMPP)2Pd(NO3)2] (1a), showing
the atom-numbering scheme (40% probability ellipsoids). Selected bond
distances (Å) and bond angles (deg): Pd(1)-O(1), 2.101(3); Pd(1)-
O(4), 2.121(3); Pd(1)-P(1), 2.2436(12); Pd(1)-P(2), 2.2473(11);
O(1)-Pd(1)-O(4), 84.13(12); P(1)-Pd(1)-P(2), 91.78(4); O(1)-
Pd(1)-P(2), 93.20(9); O(4)-Pd(1)-P(1), 90.99(9).
The geometric structures of the isomers were determined by
1
1
a combination of H, H{31P}, 13C{1H}, and 31P{1H} NMR
spectroscopy of the reaction mixtures and comparison with the
NMR data for the pure isolated solids. In each case, the data
were the same. For 2 and 5, single resonances in their 31P{1H}
NMR spectra indicated the formation of only one geometric
2
isomer. The small magnitudes of J(PP) values determined31
1
from the 13C{1H} NMR spectra and J(PtP) values of about
3500 Hz for the platinum complexes, determined32 from their
31P{1H} NMR spectra, are consistent with the formation of cis
isomers (see the Experimental Section for the data).
The structures of 2 and 5 were confirmed by X-ray crystal-
lography. Crystallographic data are listed in Table 3, and the
structures are shown in Figures 3-5. All three complexes
crystallize as the cis isomers with structures that are consistent
with the NMR data. For both 2a and 2b, the metals lie on special
positions with a crystallographic C2 axis in the coordination
plane passing through the metal atoms, which relates the two
chiral ligands as illustrated in Figures 3 and 4. Thus, the two
ligands bound to each metal center have the same absolute
configuration and the complexes are formed as racemic mixtures
of the (R,R) and (S,S) diastereomers. None of the meso (R,S)
diastereomer is observed. Complexes 2a and 2b are isomorphous
and isostructural with very similar M-P (2.1991(7) Å, 2a;
2.187(2) Å, 2b) and M-O (2.103(2) Å, 2a; 2.091(4) Å, 2b)
distances. The M-O distances are essentially the same as those
in 1a and 1b even though the ligands are chelating in 2a and
2b, which normally gives rise to a reduction in bond length
relative to monodentate ligands. Both 2a and 2b exhibit a minor
Figure 2. Structural drawing of [(DMPP)2Pt(NO3)2] (1b), showing the
atom-numbering scheme (40% probability ellipsoids). Selected bond
distances (Å) and bond angles (deg): Pt(1)-O(1), 2.098(8); Pt(1)-
O(4), 2.085(7); Pt(1)-P(1), 2.227(3); Pt(1)-P(2), 2.225(3); O(1)-
Pt(1)-O(4), 82.8(3); P(1)-Pt(1)-P(2), 93.50(11); O(1)-Pt(1)-P(2),
91.4(2); O(4)-Pt(1)-P(1), 92.4(2).
equiv of [(DMPP)2MCl2] [M ) Pd (1a), Pt (1b)] in a 1:1
mixture of CH3NO2 and CH3CN and filtration to remove silver
chloride, 2 equiv of the dienophiles DMAA, VyPy, and DPVP
were added respectively to the yellow solutions of [(DMPP)2M-
(CH3CN)2]X2. The reactions were monitored by 31P{1H} NMR
spectroscopy, and when they were judged to be complete
(several days), the solution volumes were reduced. Diethyl ether
was then added to precipitate the products as microcrystalline
solids. The nature of the products of these reactions (Scheme
1) is independent of the nature of the anion. However, with
NO3-, the reactions were somewhat slower than those with the
(30) Appleton, T. G.; Clark, H. C.; Manzer, L. E. Coord. Chem. ReV. 1973,
10, 335.
more weakly coordinating anions29 and the BF4 salts were
-
(31) Redfield, D. A.; Cary, L. W.; Nelson, J. H. Inorg. Chem. 1975, 14,
50.
(29) Strauss, S. H. Chem. ReV. 1993, 93, 927.
(32) Nelson, J. H. Coord. Chem. ReV. 1995, 139, 245.

Cycloaddition Reactions of Dimethylphenylphosphole
Inorganic Chemistry, Vol. 39, No. 15, 2000 3395
Scheme 1
amount of tetrahedral distortion as indicated by the O(1)-M(1)-
P(1)/O(1a)-M(1)-P(1a) dihedral angles, which are 14.5° (2a)
and 12.6° (2b).
The structure of 5b (Figure 5) shows that this compound also
forms exclusively as the cis isomer, consistent with the NMR
data. For this complex, as well, the two ligands are related by
a crystallographic C2 axis lying in the coordination plane passing
through the Pt atom. Here also, a racemic mixture of the (R,R)
and (S,S) diastereomers is formed. The Pt-P distances (2.238(2)
Å, average) are slightly longer than those observed for 2b, and
the Pt-N distances (2.129(5) Å, average) are longer than the
Pt-O distances in 2b. Both features probably result from slightly
increased intramolecular steric interactions in 5b compared to
2b. The platinum coordination geometry is planar, as the sum
of the angles around Pt is 360.39°.
The minor product of the reaction of [(DMPP)2Pd(CH3CN)2]-
X2 with VyPy, amounting to 25% of the crude product, is 5a.
The 31P{1H} NMR spectrum of the PF6 salt, isolated after
-
metathesis of the NO3- salt with excess NaPF6, exhibits a singlet
at δ 72.31 and a septet at δ -145.0 (1J(PF) ) 707 Hz) in a 1:1

3396 Inorganic Chemistry, Vol. 39, No. 15, 2000
Redwine et al.
Table 3. Crystallographic Data for 2a, 2b, and 5a
2a
2b
5b
empirical formula
fw
crystal system
space group
Z
C34H44B2F8N2O2P2Pd
854.67
monoclinic
C2/c
C34H44B2F8N2O2P2Pt
943.36
monoclinic
C2/c
C38H40B2F8N2P2Pt‚C3H6O
1013.45
triclinic
P1h
4
4
2
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
17.973(1)
10.6282(7)
19.741(2)
90
97.789(5)
90
3736.2(4)
1.519
25
17.961(7)
10.583(3)
19.869(4)
90
98.70(3)
90
3733.0(2)
1.678
25
10.5377(8)
12.055(2)
19.492(2)
102.653(11)
97.355(7)
109.097(14)
2102.4(4)
1.534
25
34.8
0.0397
0.0935
F
calc (g cm-3
T (°C)
)
µ (cm-1
)
6.56
39.18
R1(F)a [I > 2σ(I)]
0.0440
0.1122
1.038
0.0339
0.0762
1.045
wR2(F2)b
GOF
1.047
a Footnote a, Table 2. b Footnote b, Table 2.
Figure 4. Structural drawing of the cation of 2b, showing the atom-
numbering scheme (40% probability ellipsoids). Selected bond distances
(Å) and bond angles (deg): Pt(1)-P(1), 2.187(2); Pt(1)-O(1), 2.091(4);
P(1)-Pt(1)-P(1A), 95.91(9); O(1)-Pt(1)-O(1A), 82.4(2); O(1A)-
Pt(1)-P(1A), 91.74(13); O(1)-Pt(1)-P(1), 91.74(13).
Figure 3. Structural drawing of the cation of 2a, showing the atom-
numbering scheme (40% probability ellipsoids). Selected bond distances
(Å) and bond angles (deg): Pd(1)-P(1), 2.1991(7); Pd(1)-O(1),
2.103(2); P(1)-Pd(1)-P(1A), 93.71(4); O(1)-Pd(1)-O(1A), 84.86(11);
O(1A)-Pd(1)-P(1A), 91.66(6); O(1)-Pd(1)-P(1), 91.66(6).
Table 4. This compound crystallizes with two molecules of
acetone in the asymmetric unit and with disordered PF6- ions.
It contains a [4+2] Diels-Alder cycloadduct of VyPy and
DMPP and an ylide that resulted from nucleophilic attack of a
free DMPP molecule on the vinyl group of a coordinated VyPy,
followed by addition of two hydrogens, probably emanating
from adventitious water. The ylide is stabilized in its dipolar
form by coordination of C(20) to palladium. The coordination
geometry is planar; the sum of the angles around palladium is
360.4°. The two pyridine moieties are mutually cis, and the
phosphorus and carbon donors are cis to one another. The
metal-ligand bond lengths lie in the expected ranges. The P(2)-
C(20) (1.799(7) Å) and P(2)-C(23) (1.806(4) Å) bond lengths
are almost equal, so that the former is not a double bond. The
C(21)-C(22) (1.333(10) Å) and C(5)-C(6) (1.332(11) Å) bond
lengths are typical of carbon-carbon double bonds.
1
integrated ratio. The H and 13C{1H} chemical shifts are very
similar to those of the platinum analogue (5b), suggesting that
this complex is also a racemic mixture of the (R,R) and (S,S)
diastereomers with a cis geometry.
The 31P{1H} NMR spectrum of the major isolated product
of the reactions of [(DMPP)2Pd(CH3CN)2]X2 with VyPy,
amounting to 75% of the crude product, exhibits two doublets
at δ 105.35 and 38.47 (J(PP) ) 4.9 Hz), consistent with the
presence of two inequivalent coordinated phosphines with a cis
interrelationship. The resonance at δ 105.35 is characteristic of
a coordinated 7-phosphanorbornene,1 and the resonance at δ
38.47 is typical of a phosphole coordinated to palladium.21,22
The 1H and 13C{1H} NMR spectra are very complicated but do
not show resonances attributable to vinyl protons and carbons
and to phosphole R protons and carbons. The structure of this
unusual and unexpected product was established by X-ray
crystallography (Figure 6). Crystallographic data are listed in
1
The H and 13C{1H} NMR spectra were then completely
1
1
assigned with the aid of H{31P}, COSY, APT, and H/13C
HETCOR experiments and were found to be consistent with
the structure (see the Experimental Section for the data).

Cycloaddition Reactions of Dimethylphenylphosphole
Inorganic Chemistry, Vol. 39, No. 15, 2000 3397
Table 4. Crystallographic Data for 6A, 3B, 4A, and 4b
6a
3b
4a
4b
empirical formula
fw
crystal system
space group
Z
C38H41F12N2P4Pd‚2C3H6O
1100.16
triclinic
P1h
C52H52B2F8P4Pt‚C3H6O
1227.60
monoclinic
P21/n
C52H52B2F8P4Pd‚3C3H6O
C52H52B2F8P4Pt‚3C3H6O
1255.07
monoclinic
C2/c
1343.76
monoclinic
C2/c
2
4
4
4
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
10.384(2)
11.912(1)
21.260(2)
74.937(6)
83.354(9)
84.189(9)
2515.3(5)
1.453
25
5.77
0.0638
0.1852
10.1466(14)
23.168(2)
23.346(2)
90
91.374(9)
90
5486.5(9)
1.486
25
27.39
0.0739
0.1136
1.005
12.0940(12)
26.651(4)
19.298(2)
90
95.323(7)
90
6193.3(12)
1.168
25
12.066(2)
26.570(3)
19.350(2)
90
95.197(8)
90
6177.8(12)
1.445
25
F
calc (g cm-3
T (°C)
)
µ (mm-1
)
4.57
24.42
R1 (F)a [I > 2σ(I)]
0.0598
0.1456
1.045
0.0609
0.1548
1.034
wR2(F2)b
GOF
0.990
a Footnote a, Table 2. b Footnote b, Table 2.
Figure 5. Structural drawing of the cation of 5b, showing the atom-
numbering scheme (40% probability ellipsoids). Selected bond distances
(Å) and bond angles (deg): Pt(1)-P(1), 2.237(2); Pt(1)-P(2), 2.238(2);
Pt(1)-N(1), 2.129(5); Pt(1)-N(2), 2.128(5); P(1)-Pt(1)-P(2), 92.49(6);
N(1)-Pt(1)-N(2), 89.8(2); N(2)-Pt(1)-P(1), 88.3(2); N(2)-Pt(1)-
P(2), 90.1(2).
Figure 6. Structural drawing of the cation of 6a, showing the atom-
numbering scheme (40% probability ellipsoids). Selected bond distances
(Å) and bond angles (deg): Pd(1)-P(1), 2.221(2); Pd(1)-N(1),
2.175(6); Pd(1)-N(2), 2.146(6); Pd(1)-C(20), 2.084(6); P(2)-C(20),
1.799(7); P(2)-C(23), 1.806(4); C(5)-C(6), 1.332(11); C(20)-C(21),
1.504(9); C(21)-C(22), 1.333(10); C(22)-C(23), 1.498(10); P(1)-
Pd(1)-N(1), 91.6(2); N(1)-Pd(1)-N(2), 91.2(2); N(2)-Pd(1)-C(20),
88.7(2); C(20)-Pd(1)-P(1), 88.9(2).
The reactions of [(DMPP)2M(CH3CN)2]X2 with 2 equiv of
DPVP produced both compounds 3 and 4, the cis- and trans-
[P2MP′2]2+ species. The coordination geometry of these com-
plexes is readily determined by 31P{1H} NMR spectroscopy.
The spin systems of the phosphorus nuclei for the cis isomers
are second-order [AX]2 spin systems, whereas those for the trans
isomers are first-order A2X2 spin systems. The former give rise
to a pair of centrosymmetric complex multiplets and the latter
to a pair of triplets. The cis:trans ratios in the crude products,
as determined by 31P{1H} NMR spectroscopy, were 1.16 and
0.87 for platinum and palladium, respectively. The starting
[(DMPP)2M(CH3CN)2]2+ complexes both have the cis geometry
in solution. Ligand substitution of CH3CN by DPVP would be
expected to occur to produce cis-[(DMPP)2M(DPVP)2]2+ before
the Diels-Alder cycloaddition occurred. It is likely that cis-
trans geometric isomerization occurs at this stage at a rate that
is competitive with the rate of cycloaddition. The cycloaddition
rates are expected to be nearly the same for the palladiun and
platinum complexes, but the isomerization rate for the palladium
complexes should be faster than that for the platinum com-
plexes.33,34 As a result, the fraction of the trans isomer is greater
for palladium than for platinum. The products are configuration-
ally stable, and the geometric isomers were separated by
fractional crystallization from acetone/ether mixtures, in which
the trans isomers precipitated first.
The structures of 3b, 4a, and 4b were determined by X-ray
crystallography (Figures 7-9). Crystallographic data are listed
in Table 4. All three compounds crystallize as acetone solvates,
and all are planar, with the sums of the angles around the metals
being 359.91(5), 359.98(5), and 359.88(5)°, respectively. Com-
plex 3b possesses a C2 axis perpendicular to the coordination
plane passing through the platinum atom. The isomorphous and
isostructural complexes 4a and 4b possess crystallographic C2
(33) Hartley, F. R. The Chemistry of Platinum and Palladium; Halsted:
New York, 1973; p 313 ff.
(34) Anderson, G. K.; Cross, R. J. Chem. Soc. ReV. 1980, 9, 185.

3398 Inorganic Chemistry, Vol. 39, No. 15, 2000
Redwine et al.
Figure 9. Structural drawing of the cation of 4a, showing the atom-
numbering scheme (40% probability ellipsoids). Selected bond distances
(Å) and bond angles (deg): Pd(1)-P(1), 2.3435(13); Pd(1)-P(2),
2.350(13); C(5)-C(6), 1.328(8); P(1)-Pd(1)-P(2), 81.01(4); P(1)-
Pd(1)-P(2A), 98.93(4); P(1A)-Pd(1)-P(2), 98.93(4); P(1A)-Pd(1)-
P(2A), 81.01(4).
Figure 7. Structural drawing of the cation of 3b, showing the atom-
numbering scheme (40% probability ellipsoids). Selected bond
distances (Å) and bond angles (deg): Pt(1)-P(1), 2.312(3); Pt(1)-
P(2), 2.341(3); Pt(1)-P(3), 2.318(3); Pt(1)-P(4), 2.324(3); C(5)-C(6),
1.31(2); C(31)-C(32), 1.30(2); P(1)-Pt(1)-P(2), 81.78(11); P(1)-
Pt(1)-P(3), 95.92(11); P(2)-Pt(1)-P(4), 100.34(12); P(3)-Pt(1)-P(4),
81.87(11).
Conclusions
The complexes cis-[(DMPP)2M(CH3CN)2]X2 (M ) Pd, Pt;
X ) NO3-, BF4-, ClO4-) react with 2 equiv of the dienophiles
DMAA, VyPy, and DPVP to first produce the ligand substitution
products [(DMPP)2M(dienophile)2]X2. These ligand substitution
products undergo cis-trans isomerization when the dienophile
is DPVP but not when the dienophile is DMAA or VyPy. The
ligand substitution products then undergo two rapid sequential
metal-promoted intramolecular [4+2] Diels-Alder cycloaddi-
tion reactions to produce the final products. The final products
of these reactions all contain two chiral bidentate ligands. For
the reactions with DMAA and VyPy, only cis-geometric isomers
were formed. The reactions with DPVP yielded both the cis-
and trans-geometric isomers. In all cases, the absolute config-
uration of the first Diels-Alder cycloadduct formed on the metal
influenced the absolute configuration of the second Diels-Alder
cycloaddition product in a complementary fashion. Racemic
mixtures of the (R,R) and (S,S) diastereomers were formed, and
no meso (R,S) diastereomers were observed. The complemen-
tarity in the fitting of the two chiral ligands around the metal
center is independent of whether the two ligands are mutually
cis or trans. The nature of the anion has no influence on the
stereochemistry of the products.
An unusual ylide complex, 6a, was the major product of the
reaction of cis-[(DMPP)2Pd(CH3CN)2]X2 with VyPy. That none
of the analogous product was observed in the reaction of cis-
[(DMPP)2Pt(CH3CN)2]X2 with VyPy may be explained by the
relative thermodynamic and kinetic stabilities of the palladium
and platinum complexes of DMPP. The former undergo35
spontaneous cis-trans isomerization in solution by a mechanism
that involves dissociation of DMPP, whereas the latter do not.23
VyPy is able to displace DMPP from palladium, but not from
platinum, at some stage in the reaction, most likely after the
first Diels-Alder cycloaddition. Long after submission of this
paper, enantiomerically pure analogues of 2a and 2b were
reported.36
Figure 8. Structural drawing of the cation of 4b, showing the atom-
numbering scheme (40% probability ellipsoids). Selected bond
distances (Å) and bond angles (deg): Pt(1)-P(1), 2.324(2); Pt(1)-
P(2), 2.339(2); C(5)-C(6), 1.313(14); P(1)-Pt(1)-P(2), 81.24(7);
P(1)-Pt(1)-P(2A), 98.75(7); P(1A)-Pt(1)-P(2), 98.75(7); P(1A)-
Pt(1)-P(2A), 81.24(7).
axes lying in the coordination planes passing through the metal
atoms. For all three complexes, these C2 axes relate the two
bidentate chiral ligands to one another. Thus, in all three cases,
racemic mixtures of the (R,R) and (S,S) diastereomers are
formed, and no meso (R,S) diastereomers are observed in the
crude products. For the isomeric complexes of platinum, 3b
and 4b, there is very little difference in the Pt-P bond lengths
either within or between the complexes. This observation
suggests that the two isomers have comparable thermodynamic
stabilities, and in fact, the observed ratio of the isomers is near
unity. A similar argument should apply to the relative thermo-
dynamic stabilities of the analogous palladium complexes, which
suggests that the isomer ratio is under kinetic control.
(35) MacDougall, J. J.; Mathey, F.; Nelson, J. H. Inorg. Chem. 1980, 19,
1980.

Cycloaddition Reactions of Dimethylphenylphosphole
Inorganic Chemistry, Vol. 39, No. 15, 2000 3399
31P{1H} NMR (CD3NO2): δ 101.30. H NMR (CD3NO2): δ 7.71 (m,
1
Experimental Section
3
2H, Hp), 7.54 (m, 4H, Hm), 7.19 (m, 4H, Ho), 3.50 (dddd, J(PH) )
24.5 Hz, 3J(H2H4) ) 10.8 Hz, 3J(H2H3) ) 5.0 Hz, 3J(H1H2) ) 1.5 Hz,
A. Reagents and Physical Measurements. All chemicals were of
reagent grade and were used as received from commercial sources
(Aldrich, Fisher Scientific, or Organometallics for DPVP). Elemental
analyses were performed by Galbraith Laboratories, Knoxville, TN.
Melting points were determined on a Mel-Temp apparatus and are
uncorrected. FT-IR spectra were recorded for Nujol mulls on NaCl
windows by using a Perkin-Elmer BX spectrometer. 1H, 1H{31P}, 13C-
{1H}, and 31P{1H} NMR spectra were recorded at 499.8, 499.8, 125.7,
and 202.3 MHz, respectively, on a Varian Unity Plus 500 FT-NMR
spectrometer. Proton and carbon chemical shifts are relative to internal
Me4Si or solvent resonances and phosphorus chemical shifts are relative
to the resonance of external 85% H3PO4(aq) with positive values being
downfield of the respective reference.
3
2H, H2), 3.31 (s, 6H, NCH3), 3.26 (s, 6H, NCH3), 3.24 (dd, J(H3H5)
3
3
) 2.5 Hz, J(H4H5) ) 1.0 Hz, 2H, H5), 2.84 (d, J(H1H2) ) 1.5 Hz,
3
3
3
2H, H1), 2.81 (dddd, J(H3H4) ) 13.5 Hz, J(PH) ) 7.5 Hz, J(H2H3)
) 5.0 Hz, 3J(H3H5) ) 2.5 Hz, 2H, H3), 2.41 (dddd, 3J(PH) ) 37.0 Hz,
2J(H3H4) ) 13.5 Hz, J(H2H4) ) 10.8 Hz, J(H4H5) ) 1.0 Hz, 2H,
H4), 1.65 (s, 6H, CCH3), 1.40 (s, 6H, CCH3). 13C{1H} NMR (CD3-
NO2): δ 178.37 (s, CO), 135.42 (s, C6 or C5), 134.25 (s, C5 or C6),
3
3
133.29 (AXX′, | J(PC) + 4J(PC)| ) 11.3 Hz, Co), 133.24 (s, Cp), 129.19
2
3
5
2
(AXX′, J(PC) ) 10.5 Hz, J(PC) ) 0.4 Hz, J(PP) ) 8.3 Hz, Cm),
122.49 (AXX′, 1J(PC) ) 57.8 Hz, 3J(PC) ) 3.6 Hz, Ci), 49.22 (AXX′,
1J(PC) ) 36.1 Hz, 3J(PC) ) 2.6 Hz, C1), 45.63 (AXX′, 1J(PC) ) 37.6
Hz, 3J(PC) ) 2.3 Hz, C4), 39.67 (AXX′, 2J(PC) ) 17.6 Hz, 4J(PC) )
1.2 Hz, 2J(PP) ) 8.3 Hz, C2), 37.95 (s, NCH3), 36.70 (s, NCH3), 30.09
B. Syntheses. [(DMPP)2Pd(NO3)2] (1a). To a solution of 0.553 g
(1.00 mmol) of cis-[(DMPP)2PdCl2]21,22 in 25 mL of CH3CN was added
0.340 g (2.00 mmol) of AgNO3. A curdy white precipitate formed
immediately in a lemon-yellow solution. The mixture was stirred at
ambient temperature, protected from light with aluminum foil for 1 h,
and filtered to remove AgCl, after which the volume of the filtrate
was reduced to 10 mL on a rotary evaporator. Ether (10 mL) was added
to the solution, and the mixture was allowed to stand at ambient
temperature for 4 h. The microcrystalline yellow precipitate that formed
was isolated by filtration and dried under vacuum to yield 0.54 g (89%)
of 1a. Mp: 187-188 °C. Anal. Calcd for C24H26N2O6P2Pd: C, 47.52;
H, 4.29; N, 4.62. Found: C, 47.39; H, 4.17; N, 4.68. 13C{1H} NMR
2
4
2
(AXX′, J(PC) ) 25.2 Hz, J(PC) ) 0.5 Hz, J(PP) ) 8.3 Hz, C3),
12.78 (AXX′, | J(PC) + 5J(PC)| ) 3.6 Hz, CCH3), 12.59 (AXX′,
3
3
5
| J(PC) + J(PC)| ) 2.8 Hz, CCH3).
2b. Yield: 0.80 g (85%) of colorless crystals. Mp: 273-275 °C.
IR (Nujol): νCdO 1583, 1456 cm-1. Anal. Calcd for C34H44B2F8N2O2P2-
Pt: C, 43.30; H, 4.67; N, 2.97. Found: C, 43.16; H, 4.71; N, 3.02.
31P{1H} NMR (CD3NO2): δ 74.4, 1J(PtP) ) 3560 Hz. 1H NMR (CD3-
NO2): δ 7.66 (m, 2H, Hp), 7.49 (m, 4H, Hm), 7.13 (m, 2H, Ho), 3.50
3
3
3
(dddd, J(PH) ) 22.0 Hz, J(H2H4) ) 10.5 Hz, J(H2H3) ) 4.5 Hz,
3J(H1H2) ) 1.0 Hz, 2H, H2), 3.37 (s, 6H, NCH3), 3.33 (s, 6H, NCH3),
3.19 (apparent t, 2J(PH) ) 3J(H4H5) ) 1.5 Hz, 2H, H5), 2.97 (apparent
t, 2J(PH) ) 3J(H1H2) ) 1.0 Hz, 2H, H1), 2.83 (apparent ddt, 2J(H3H4)
) 13.0 Hz, 3J(H2H3) ) 4.5 Hz, 3J(PH) ) 3J(H3H5) ) 1.5 Hz, 2H, H3),
(CD3NO2): δ 157.69 (AXX′, | J(PC) + 4J(PC)| ) 12.7 Hz, Câ), 132.51
2
(s, Cp), 132.41 (AXX′, | J(PC) + 4J(PC)| ) 12.3 Hz, Co), 129.23
2
3
2
3
2.29 (dddd, J(PH) ) 35.5 Hz, J(H3H4) ) 13.0 Hz, J(H2H4) ) 10.5
3
5
1
(AXX′, | J(PC) + J(PC)| ) 12.1 Hz, Cm), 123.12 (AXX′, | J(PC) +
3
Hz, J(H4H5) ) 1.5 Hz, 2H, H4), 1.67 (s, 6H, CCH3), 1.40 (s, 6H,
3J(PC)| ) 60.6 Hz, Ci), 119.18 (AXX′, | J(PC) + 3J(PC)| ) 60.6 Hz,
1
CCH3). 13C{1H} NMR (CD3NO2): δ 179.03 (s, CO), 135.05 (s, C6 or
C5), 133.12 (s, Cp), 133.06 (AXX′, 2J(PC) ) 12.1 Hz, 4J(PC) ) -1.8
3
5
CR), 16.66 (AXX′, | J(PC) + J(PC)| ) 14.8 Hz, CH3).
[(DMPP)2Pt(NO3)2] (1b). Similarly, from 0.642 g (1.00 mmol) of
cis-[(DMPP)2PtCl2]23,24 and 0.340 g (2.00 mmol) AgNO3 was obtained
0.58 g (90%) of colorless microcrystals of 1b. Mp: 210-211 °C. Anal.
Calcd for C24H26N2O6P2Pt: C, 41.46; H, 3.74; N, 4.03. Found: C, 41.35;
2
2
4
Hz, J(PP) ) 10.7 Hz, Co), 132.86 (AXX′, | J(PC) + J(PC)| ) 1.9
3
5
Hz, C5 or C6), 129.01 (AXX′, J(PC) ) 10.7 Hz, J(PC) ) -0.6 Hz,
2J(PP) ) 10.7 Hz, Cm), 122.26 (AXX′, | J(PC) +3J(PC)| ) 70.0 Hz,
1
1
3
2
Ci), 47.29 (AXX′, J(PC) ) 40.5 Hz, J(PC) ) -1.2 Hz, J(PP) )
H, 3.68; N, 4.12. 13C{1H} NMR (CD3NO2): δ 157.41 (AXX′, | J(PC)
2
1
3
10.7 Hz, C4), 44.86 (AXX′, J(PC) ) 42.7 Hz, J(PC) ) -0.3 Hz,
4
2
4
+ J(PC)| ) 14.7 Hz, Câ), 132.42 (AXX′, | J(PC) + J(PC)| ) 11.6
2J(PP) ) 10.7 Hz, C1), 39.85 (AXX′, J(PC) ) 15.6 Hz, J(PC) )
2
4
4
Hz, Co), 132.39 (AXX′, | J(PC) + 6J(PC)| ) 1.5 Hz, Cp), 129.02 (AXX′,
2
5
7
-0.7 Hz, J(PP) ) 10.7 Hz, C2), 38.47 (AXX′, | J(PC) + J(PC)| )
3
5
1
3
| J(PC) + J(PC)| ) 11.9 Hz, Cm), 123.47 (AXX′, | J(PC) + J(PC)|
5
7
3.3 Hz, NCH3), 37.35 (AXX′, | J(PC) + J(PC)| ) 2.9 Hz, NCH3),
1
3
) 67.7 Hz, Ci), 119.13 (AXX′, J(PC) ) 63.2 Hz, J(PC) ) 4.3 Hz,
2
4
2
30.11 (AXX′, J(PC) ) 22.4 Hz, J(PC) ) -0.1 Hz, J(PP) ) 10.7
2J(PP) ) 30.8 Hz, CR), 16.57 (AXX′, | J(PC) + J(PC)| ) 15.2 Hz,
3
5
Hz, C3), 12.50 (AXX′, | J(PC) + 5J(PC)| ) 4.3 Hz, CCH3), 12.33
3
CH3).
3
5
(AXX′, | J(PC) + J(PC)| ) 3.5 Hz, CCH3).
Diels-Alder Cycloadducts. All of the cycloadducts were prepared
by the same general method. To a solution containing 1.00 mmol of
[(DMPP)2MCl2] in 25 mL of CH3CN and 25 mL of CH3NO2 was added
2.00 mmol of AgBF4. After the mixture was stirred for 1 h, protected
from light with aluminum foil, it was filtered to remove AgCl, and 2.1
equiv of the respective dienophile was added to the filtrate. The reaction
mixture was allowed to stand at ambient temperature for 4 days, the
volume was reduced to 5 mL on a rotary evaporator, and ether was
added to precipitate the product, which was isolated by filtration, dried
under vacuum, and recrystallized from an acetone/ether mixture.
3a. This compound could not be isolated in isomerically pure form.
Consequently, the following NMR spectral data are assigned from the
NMR spectra of cis and trans mixtures. 31P{1H} (CD3NO2): δ 112.95
2
2
2
2
(PA), 35.04 (PX), J(AX′) ) J(A′X) ) 278.1 Hz, J(AA′) ) J(XX′)
) 11.2 Hz, 2J(AX) ) 2J(A′X′) ) 36.9 Hz. 1H NMR (CD3NO2): δ 6.8-
7.9 (m, 30H, Ph), 3.56 (m, 2H, H2), 3.52 (m, 2H, H5), 3.18 (m, 2H,
H1), 2.94 (m, 2H, H3), 2.42 (m, 2H, H4), 1.81 (s, 6H, CH3), 1.36 (s,
6H, CH3).
3b. Yield: 0.42 g (36%) of colorless crystals. Mp: 174-175 °C.
Anal. Calcd for C52H52B2F8P4Pt: C, 53.42; H, 4.45. Found: C, 53.28;
H, 4.29. 31P{1H} NMR (CD3NO2): δ 101.18 (PA, 1J(PtP) ) 2114 Hz),
30.13 (PX, 1J(PtP) ) 2250 Hz), 2J(AX′) ) 2J(A′X) ) 270.9 Hz, 2J(AA′)
2a. Yield: 0.68 g (80%) of pale yellow crystals. Mp: 240-242 °C.
IR (Nujol): νCdO 1590, 1436 cm-1. The values of the aminocarbonyl
CO stretching frequencies for 2a and 2b indicate oxygen coordination
and a cis geometry.37 Anal. Calcd for C34H44B2F8N2O2P2Pd: C, 47.80;
H, 5.15; N, 3.28. Found: C, 47.69; H, 5.01; N, 3.32.
2
2
2
1
) 17.3 Hz, J(XX′) ) 11.1 Hz, J(AX) ) J(A′X′) ) -23.8 Hz. H
NMR (CD3NO2): δ 7.1-7.7 (m, 30H, Ph), 3.65 (m, 2H, H2), 3.56 (m,
2H, H5), 3.02 (m, 2H, H1), 3.00 (m, 2H, H3), 2.29 (m, 2H, H4), 1.84 (s,
6H, CH3), 1.34 (s, 6H, CH3). 13C{1H} NMR (CD3NO2): δ 136 47
(AA′MM′X, 3J(PtC) ) 24.9 Hz, | J(PC) + 4J(PC)| ) 1.4 Hz, C6),
2
135.05 (AA′MM′X, | J(PC) + 4J(PC)| ) 11.7 Hz, Co), 133.50 (s, Cp),
2
2
4
133.46 (AA′MM′X, | J(PC) + J(PC)| ) 9.6 Hz, Co), 132.98 (s, Cp),
132.79 (s, Cp), 132.34 (AA′MM′X, | J(PC) + 4J(PC)| ) 10.8 Hz, Co),
2
129.75 (AA′MM′X, | J(PC) + 5J(PC)| ) 11.2 Hz, Cm), 129.39
3
3
5
(AA′MM′X, | J(PC) + J(PC)| ) 11.2 Hz, Cm), 129.28 (AA′MM′X,
| J(PC) + 5J(PC)| ) 11.2 Hz, Cm), 128.14 (AA′MM′X, | J(PC) +
3
2
4J(PC)| ) 17.5 Hz, C5), 125.50 (AA′MM′X,| J(PC) + 3J(PC)| ) 55.7
1
(36) Leung, P.-H.; He, G.; Lang, H.; Liu, A.; Loh, S.-K.; Selvaratnam, S.;
(37) James, B. R.; Ochaiai, E.; Rempel, J. L. Inorg. Nucl. Chem. Lett. 1971,
7, 781.
Mok, K. F.; White, A. J. P.; Williams, D. J. Tetrahedron 2000, 56, 7.

3400 Inorganic Chemistry, Vol. 39, No. 15, 2000
Redwine et al.
1
Hz, Ci), 124.82 (AA′MM′X, | J(PC) + 3J(PC)| ) 54.7 Hz, Ci), 123.20
2H, H5), 3.41 (ddd, 2J(PH) ) 4.5 Hz, 4J(H1H5) ) 2.0 Hz, 3J(H1H2) )
(AA′MM′X, | J(PC) + 3J(PC)| ) 54.2 Hz, Ci), 54.69 (AA′MM′X,
1.0 Hz, 2H, H1), 2.75 (dddd, J(PH) ) 29.0 Hz, J(H3H4) ) 13.5 Hz,
1
3
2
| J(PC) + 3J(PC)| ) 38.5 Hz, C1), 47.54 (AA′MM′X, | J(PC) + 3J(PC)|
3J(H2H4) ) 10.8 Hz, J(H4H5) ) 2.5 Hz, 2H, H4), 2.63 (apparent ddt,
1
1
3
) 36.2 Hz, C2), 33.84 (AA′MM′X, | J(PC) + 3J(PC)| ) 35.2 Hz, C4),
2J(H3H4) ) 13.5 Hz, 2J(H2H3) ) 6.3 Hz, 3J(H3H5) ) 3J(PH) ) 2.5 Hz,
1
2
4
4
5
31.92 (AA′MM′X, | J(PC) + J(PC)| ) 16.8 Hz, C3), 13.04 (AA′M-
2H, H3), 1.78 (dq, J(PH) ) J(HH) ) 1.0 Hz, 6H, CH3), 1.74 (dq,
3
5
3
5
M′X, | J(PC) + J(PC)| ) 2.6 Hz, CH3), 12.11 (AA′MM′X, | J(PC)
4J(PH) ) 2.0 Hz, J(HH) ) 1.0 Hz, 6H, CH3). 13C{1H} NMR (CD3-
5
2
+ J(PC)| ) 3.3 Hz, CH3).
NO2): δ 160.22 (Ce), 148.51 (Ca), 144.11 (Cc), 135.95 (d, J(PC) )
2
4a. Yield: 0.37 g (34%) of pale yellow crystals. Mp: 189-191 °C.
Anal. Calcd for C52H52B2F8P4Pd: C, 57.81; H, 4.81. Found: C, 57.59;
H, 4.64. 31P{1H} NMR (CD3NO2): δ 116.96 (t, PA), 33.90 (t, PX),
2J(AX) ) 24.0 Hz. 1H NMR (CD3NO2): δ 6.8-7.9 (m, 30H, Ph), 3.76
(s, 2H, H5), 3.56 (m, 2H, H2), 3.46 (s, 2H, H1), 3.01 (m, 2H, H3), 2.18
(m, 2H, H4), 1.60 (s, 6H, CH3), 1.46 (s, 6H, CH3). 13C{1H} NMR (CD3-
8.3 Hz, C5 or C6), 135.65 (d, J(PC) ) 10.4 Hz, C5 or C6), 134.87 (d,
4J(PC) ) 2.8 Hz, Cp), 133.43 (d, J(PC) ) 9.1 Hz, Co), 130.98 (d,
2
3J(PC) ) 12.2 Hz, Cm), 130.40 (Cd), 127.37 (Cb), 127.16 (d, 1J(PC) )
1
1
103.6 Hz, Ci), 51.44 (d, J(PC) ) 64.6 Hz, C1), 48.21 (d, J(PC) )
2
2
64.2 Hz, C4), 46.42 (d, J(PC) ) 16.0 Hz, C2), 35.29 (d, J(PC) )
13.6 Hz, C3), 15.22 (d, 3J(PC) ) 5.2 Hz, CH3), 14.69 (d, 3J(PC) ) 4.5
Hz, CH3).
2
NO2): δ 137.56 (AA′MM′X, | J(PC) + 4J(PC)| ) 1.3 Hz, C6), 134.65
2
4
(AA′MM′X, | J(PC) + J(PC)| ) 13.3 Hz, Co), 133.94 (AA′MM′X,
5b. Yield: 0.72 g (75%) of colorless crystals. Mp: 233-235 °C.
Anal. Calcd for C38H40B2F8N2P2Pt: C, 47.79; H, 4.68; N, 2.93.
Found: C, 47.65; H, 4.57; N, 2.84. 31P{1H} NMR (CD3NO2): δ 66.25,
1J(PtP) ) 2975 Hz. 1H NMR (CD3NO2): δ 8.19 (apparent td, 3J(HbHc)
) 3J(HcHd) ) 7.5 Hz, 4J(HaHc) ) 1.5 Hz, 2H, Hc), 8.00 (dd, 3J(HaHb)
| J(PC) + 4J(PC)| ) 13.1 Hz, Co), 133.51 (s, Cp), 133.43 (s, Cp), 131.89
2
2
(s, Cp), 131.77 (AA′MM′X, | J(PC) + 4J(PC)| ) 10.2 Hz, Co), 130.68
2
4
(AA′MM′X, | J(PC) + J(PC)| ) 17.5 Hz, C5), 129.97 (AA′MM′X,
| J(PC) + 5J(PC)| ) 11.7 Hz, Cm), 129.92 (AA′MM′X, | J(PC) +
3
3
5J(PC)| ) 11.8 Hz, Cm), 128.81 (AA′MM′X, | J(PC) + 5J(PC)| ) 10.1
) 5.8 Hz, J(HaHc) ) 1.5 Hz, 2H, Ha), 7.81 (dd, J(HcHd) ) 7.5 Hz,
4J(HbHd) ) 1.5 Hz, 2H, Hd), 7.69 (m, 2H, Hp), 7.49 (m, 4H, Hm), 7.46
(ddd, 3J(HbHc) ) 7.5 Hz, 3J(HaHb) ) 5.8 Hz, 4J(HbHd) ) 1.5 Hz, 2H,
3
4
3
1
Hz, Cm), 126.36 (AA′MM′X, | J(PC) + 3J(PC)| ) 50.3 Hz, Ci), 124.45
1
3
(AA′MM′X, | J(PC) + J(PC)| ) 46.1 Hz, Ci), 122.35 (AA′MM′X,
| J(PC) + 3J(PC)| ) 52.0 Hz, Ci), 55.29 (AA′MM′X, | J(PC) + 3J(PC)|
Hb), 7.10 (b m, 4H, Ho), 3.74 (dddd, J(PH) ) 24.0 Hz, J(H2H4) )
1
1
3
2
) 28.9 Hz, C2), 33.76 (AA′MM′X, | J(PC) + 3J(PC)| ) 38.8 Hz, C4),
10.8 Hz, 3J(H2H3) ) 4.5 Hz, 3J(H1H2) ) 0.5 Hz, 2H, H2), 3.63 (apparent
1
29.80 (AA′MM′X, | J(PC) + 4J(PC)| ) 17.8 Hz, C3), 13.30 (s, CH3),
ddt, J(H3H4) ) 13.3 Hz, J(H2H3) ) 4.5 Hz, J(PH) ) J(H3H5) )
2.3 Hz, 2H, H3), 3.23 (apparent dq, 3J(H3H5) ) 2.3 Hz, 2J(PH) )
2
3
3
3
3
12.35 (s, CH3).
3
2
4b. Yield: 0.29 g (25%) of pale yellow crystals. Mp: 210-212 °C.
Anal. Calcd for C52H52B2F8P4Pt: C, 53.42; H, 4.75. Found: C, 53.56;
4J(H1H5) ) J(H4H5) ) 1.5 Hz, 2H, H5), 2.84 (apparent td, J(PH) )
4J(H1H5) ) 1.5 Hz, 3J(H1H2) ) 0.5 Hz, 2H, H1), 2.56 (dddd, 3J(PH) )
H, 4.54. 31P{1H} NMR (CD3NO2): δ 104.58 (t, J(PtP) ) 2048 Hz,
35.5 Hz, J(H3H4) ) 13.3 Hz, J(H2H4) ) 10.8 Hz, J(H4H5) ) 1.5
5 5
1
2
2
3
1
3
1
PA), 27.13 (t, J(PtP) ) 2405 Hz, J(PAPX) ) 19.5 Hz, PX). H NMR
(CD3NO2): δ 6.7-7.9 (m, 30H, Ph), 3.73 (s, 2H, H5), 3.65 (m, 2H,
H2), 3.29 (s, 2H, H1), 2.97 (m, 2H, H3), 2.07 (m, 2H, H4), 1.60 (s, 6H,
CH3), 1.43 (s, 6H, CH3). 13C{1H} NMR (CD3NO2): δ 138.96
Hz, 2H, H4), 1.78 (q, J(HH) ) 0.5 Hz, 6H, CH3), 1.41 (q, J(HH) )
0.5 Hz, 6H, CH3). 13C{1H} NMR (CD3NO2): δ 163.86 (Ce), 153.40 (d,
3J(PC) ) 2.5 Hz, Ca), 142.21 (Cc), 133.96 (C5 or C6), 133.28 (AXX′,
| J(PC) + 4J(PC)| ) 9.9 Hz, Co), 133.02 (Cp), 132.34 (C5 or C6), 128.99
2
(AA′MM′X, 3J(PtC) ) 24.3 Hz, | J(PC) + 4J(PC)| ) 1.4 Hz, C6),
(AXX′, 3J(PC) ) 12.3 Hz, 5J(PC) ) -1.5 Hz, 2J(PP) ) 14.0 Hz, Cm),
2
136.30 (AA′MM′X, | J(PC) + 4J(PC)| ) 13.2 Hz, Co), 135.54
128.43 (Cd), 125.24 (Cb), 120.45 (AXX′, | J(PC) + J(PC)| ) 63.1
2
1
3
(AA′MM′X, | J(PC) + 4J(PC)| ) 12.6 Hz, Co), 135.28 (s, Cp), 135.00
Hz, Ci), 50.14 (AXX′, | J(PC) + 3J(PC)| ) 40.2 Hz, C1), 47.14 (AXX′,
2
1
2
4
1
3
2
(s, Cp), 133.39 (s, Cp), 133.18 (AA′MM′X, | J(PC) + J(PC)| ) 12.5
| J(PC) + J(PC)| ) 48.1 Hz, C4), 46.31 (AXX′, J(PC) ) 14.2 Hz,
4J(PC) ) 3.1 Hz, 2J(PP) ) 14.0 Hz, C2), 34.37 (AXX′, 2J(PC) ) 24.7
3
Hz, Co), 131.50 (AA′MM′X, | J(PC) + 5J(PC)| ) 11.4 Hz, Cm), 131.35
3
5
3
(AA′MM′X, | J(PC) + J(PC)| ) 11.2 Hz, Cm), 130.66 (AA′MM′X,
Hz, 4J(PC) ) 0.4 Hz, 2J(PP) ) 14.0 Hz, C3), 12.54 (AXX′, | J(PC) +
| J(PC) + 4J(PC)| ) 15.7 Hz, C5), 130.15 (AA′MM′X, | J(PC) +
5J(PC)| ) 1.1 Hz, CH3), 12.35 (AXX′, | J(PC) + J(PC)| )3.6 Hz,
2
3
3
5
5J(PC)| ) 10.4 Hz, Cm), 127.32 (AA′MM′X, | J(PC) + 3J(PC)| ) 58.1
CH3).
1
1
Hz, Ci), 124.77 (AA′MM′X, | J(PC) + 3J(PC)| ) 56.2 Hz, Ci), 123.44
6a. Yield: 0.48 g (55%) of pale yellow crystals. Mp: 205-207 °C.
Anal. Calcd for C38H42B2F8N2P2Pd: C, 52.56; H, 4.84; N, 3.23.
Found: C, 52.43; H, 4.67; N, 3.14.
(AA′MM′X, | J(PC) + 3J(PC)| ) 59.8 Hz, Ci), 56.05 (AA′MM′X,
1
| J(PC) + 3J(PC)| ) 40.0 Hz, C1), 50.92 (AA′MM′X, | J(PC) + 3J(PC)|
1
1
) 34.8 Hz, C2), 34.82 (AA′MM′X, | J(PC) + 3J(PC)| ) 35.7 Hz, C4),
1
2
4
31.30 (AA′MM′X, | J(PC) + J(PC)| ) 18.9 Hz, C3), 14.71 (AA′M-
3
5
3
M′X, | J(PC) + J(PC)| ) 2.1 Hz, CH3), 13.70 (AA′MM′X, | J(PC)
5
+ J(PC)| ) 2.9 Hz, CH3).
-
5a. This compound was isolated as the PF6 salt obtained by
metathesis of the NO3- product with excess NaPF6 in CH3NO2. Yield:
0.18 g (18%) of pale yellow microcrystals. Mp: 186-187 °C. Anal.
Calcd for C38H40F12N2P4Pd: C, 46.44; H, 4.07; N, 2.85. Found: C,
46.29; H, 3.88; N, 2.67.
31P{1H} NMR (CD3NO2): δ 105.35 (d, P7), 38.47 (d, +P, J(PP) )
4.9 Hz). 1H NMR (CD3NO2): δ 8.42 (dd, 3J(Ha′Hb′) ) 6.0 Hz, 4J(Ha′Hc′)
3
3
) 1.5 Hz, 1H, Ha′), 8.23 (apparent td, J(Hc′Hd′) ) J(Hb′Hc′) ) 7.5
Hz, 4J(Ha′Hc′) ) 1.5 Hz, 1H, Hc′), 7.96 (apparent td, 3J(HcHd) ) 3J(HbHc)
4
3
) 7.5 Hz, J(HaHc) ) 1.5 Hz, 1H, Hc), 7.88 (dd, J(Hc′Hd′) ) 7.5 Hz,
4J(Hb′Hd′) ) 1.0 Hz, 1H, Hd′), 7.80 (m, 2H, Ho), 7.71 (ddd, J(Hb′Hc′)
3
) 7.5 Hz, 3J(Ha′Hb′) ) 6.0 Hz, 4J(Hb′Hd′) ) 1.0 Hz, 1H, Hb′), 7.64 (dd,
3J(HcHd) ) 7.5 Hz, J(HbHd) ) 1.5 Hz, 1H, Hd), 7.62 (m, 1H, Hp),
4
3
4
7.51 (dd, J(HaHb) ) 6.0 Hz, J(HaHc) ) 1.5 Hz, 1H, Ha), 7.42 (m,
31P{1H} NMR (CD3NO2): δ 72.31, -145.00 (septet, J(PF) ) 707
5H, Hm, Hp), 7.18 (ddd, 3J(HbHc) ) 7.5 Hz, 3J(HaHb) ) 6.0 Hz, 4J(HbHd)
1
1
3
4
2
Hz). H NMR (CD3NO2): δ 8.76 (dd, J(HaHb) ) 6.0 Hz, J(HaHc) )
) 1.5 Hz, 1H, Hb), 7.00 (m, 2H, Ho), 4.97 (dddd, J(HH) ) 14.0 Hz,
3
3
4
2
1.5 Hz, 2H, Ha), 8.52 (apparent td, J(HbHc) ) J(HcHd) ) 7.5 Hz,
4J(HH) ) 10.8 Hz, J(HH) ) 7.3 Hz, J(PH) ) 3.0 Hz, 1H, P+CH2),
2 2 4
4J(HaHc) ) 1.5 Hz, 2H, Hc), 8.01 (dd, 3J(HcHd) ) 7.5 Hz, 4J(HbHd) )
4.20 (dddd, J(PH) ) 35.0 Hz, J(HH) ) 14.0 Hz, J(HH) ) 8.0 Hz,
4J(HH) ) 1.5 Hz, 1H, P+CH2), 3.94 (apparent dtd, 3J(H3H5) ) 2.0 Hz,
3
3
1.0 Hz, 2H, Hd), 7.96 (ddd, J(HbHc) ) 7.5 Hz, J(HaHb) ) 6.0 Hz,
4J(HbHd) ) 1.0 Hz, 2H, Hb), 7.83 (m, 4H, Ho), 7.69 (m, 2H, Hp), 7.59
(m, 4H, Hm), 3.58 (dddd, 3J(PH) ) 21.0 Hz, 3J(H2H4) ) 10.8 Hz,
3J(H4H5) ) J(H1H5) ) 1.5 Hz, J, J(H1H2) ) 1.5 Hz, 1H, H2), 3.36
4
2
3
(dddd, J(H3H4) ) 13.5 Hz, 3J(H2H3) ) 5.0 Hz, 3J(PH) ) 3.0 Hz,
2
3J(H2H3) ) 6.3 Hz, J(H1H2) ) 1.0 Hz, 2H, H2), 3.45 (apparent dtd,
3J(H3H5) ) 2.0 Hz, 1H, H3), 3.32 (dddd, 2J(PH) ) 15.5 Hz, 2J(HH) )
3
2J(PH) ) 7.0 Hz, 3J(H3H5) ) 3J(H4H5) ) 2.5 Hz, 4J(H1H5) ) 2.0 Hz,
13.8 Hz, J(HH) ) 10.8 Hz, J(HH) ) 8.0 Hz, 1H, P+CH2 (ring)),
4
4

Cycloaddition Reactions of Dimethylphenylphosphole
Inorganic Chemistry, Vol. 39, No. 15, 2000 3401
1
Figure 10. Expansions of the 499.8 MHz H COSY-45 spectrum of
6a in CD3NO2 in the aromatic (top) and aliphatic (bottom) regions.
Figure 11. Expansions of the 125.7 MHz 13C/1H HETCOR spectrum
of 6a in CD3NO2 in the aromatic (top) and aliphatic (bottom) regions.
2
3
4
3.21 (apparent q, J(PH) ) J(H1H2) ) J(H1H5) ) 1.5 Hz, 1H, H1),
2
2
4
3.00 (dddd, J(PH) ) 15.5 Hz, J(HH) ) 13.8 Hz, J(HH) ) 7.3 Hz,
23.44 (d, 1J(PC) ) 32.8 Hz, PdCH), 17.84 (d, 3J(PC) ) 16.0 Hz, CH3
4J(HH) ) 1.5 Hz, 1H, P+CH2 (ring)), 2.84 (dd, J(PH) ) 12.0 Hz,
3
3
(P+ ring)), 14.75 (d, J(PC) ) 13.2 Hz, CH3 (norbornene)), 12.83 (d,
2J(PH) ) 7.5 Hz, 1H, PdCH (ring)), 2.72 (dddd, J(PH) ) 36.0 Hz,
3
3
3J(PC) ) 3.4 Hz, CH3 (P+ ring)), 12.49 (d, J(PC) ) 3.3 Hz, CH3
2J(H3H4) ) 13.5 Hz, J(H2H4) ) 10.5 Hz, J(H4H5) ) 1.5 Hz, 1H,
3
3
(norbornene)). Expansions of the COSY and 13C/1H HETCOR spectra
that were essential for the assignments of the 1H and 13C chemical shifts
are shown in Figures 10 and 11, respectively.
2
3
H4), 2.62 (dd, J(HH) ) 19.5 Hz, J(PH) ) 13.0 Hz, 1H, PyCH2),
5
5
2.29 (q, J(HH) ) 0.5 Hz, 3H, CH3 (norbornene)), 1.94 (q, J(HH) )
0.5 Hz, 3H, CH3 (P+ ring)), 1.57 (q, J(HH) ) 0.5 Hz, 3H, CH3 (P+
5
ring)), 1.40 (q, 5J(HH) ) 0.5 Hz, 3H, CH3 (norbornene)), 1.20 (d,
2J(HH) ) 19.5 Hz, 1H, PyCH2). 13C{1H} NMR (CD3NO2): δ 164.31
(Ce), 158.62 (d, 3J(PC) ) 5.0 Hz, Ce′), 151.41 (Ca), 151.26 (Ca′), 141.56
(Cc′), 140.31 (Cc), 136.56 (dd, 2J(PC) ) 8.8 Hz, 4J(PC) ) 1.0 Hz, C6),
134.98 (C5), 134.32 (C5′), 133.83 (d, 4J(PC) ) 2.9 Hz, Cp), 133.26 (d,
C. Kinetics Measurements. Solutions containing 100 mg of
[(DMPP)2M(NO3)2] and 2.2 equiv of the dienophile in 4 mL of CH3-
CN and 1 mL of CD3NO2 were placed in 10 mm NMR tubes. The
reactions were monitored by 202.3 MHz 31P{1H} NMR spectroscopy
at 40 °C using the instruments temperature regulation ((1 °C) and
kinetics routine. Typically, 200 transients were acquired for each time
interval.
4J(PC) ) 2.4 Hz, Cp), 132.35 (d, J(PC) ) 9.4 Hz, Co), 129.70 (d,
2
3J(PC) ) 7.8 Hz, Cm), 129.62 (d, J(PC) ) 5.3 Hz, Co), 129.58 (d,
2
3J(PC) ) 10.7 Hz, Cm), 128.50 (Cd), 126.46 (d, 6J(PC) ) 1.0 Hz, C6),
D. X-ray Data Collection and Processing. Crystals of the com-
plexes were obtained from acetone/ether mixtures, mounted on glass
fibers coated with epoxy, and placed on a Siemens P4 diffractometer.
Intensity data were taken in the ω mode at 298 K with Mo KR graphite-
monochromated radiation (λ ) 0.710 73 Å). Three check reflections
monitored every 100 reflections showed random (<2%) variation during
4
1
126.27 (d, J(PC) ) 2.6 Hz, Cd′), 125.31 (d, J(PC) ) 75.3 Hz, Ci),
2
1
125.15 (d, J(PC) ) 18.4 Hz, C6′), 122.57 (d, J(PC) ) 73.0 Hz, Ci),
1
2
50.16 (d, J(PC) ) 32.4 Hz, C1), 46.57 (d, J(PC) ) 17.5 Hz, C2),
45.72 (d, 1J(PC) ) 33.6 Hz, C4), 34.70 (d, 2J(PC) ) 51.0 Hz, PyCH2),
2
1
33.69 (d, J(PC) ) 27.9 Hz, C3), 32.85 (d, J(PC) ) 6.0 Hz, P+CH2),

3402 Inorganic Chemistry, Vol. 39, No. 15, 2000
Redwine et al.
the data collections. The data were corrected for Lorentz and polariza-
tion effects and for absorption using an empirical model derived from
azimuthal data collections, except for the case of 4b, for which XABS238
was used. Scattering factors and corrections for anomalous dispersions
were taken from a standard source.39 Calculations were performed with
the Siemens SHELXTL PLUS version 5.03 and 5.10 software packages
on a personal computer. The structures were solved by direct (1a, 4a,
5b) or Patterson (1b, 2a, 2b, 3b, 4b, 6a) methods. Anisotropic thermal
parameters were assigned to all non-hydrogen atoms, and hydrogen
atoms were refined at calculated positions with a riding model in which
the C-H vector was fixed at 0.96 Å.
Acknowledgment. This research was supported by an award
from the Research Corp., for which we express our grateful
appreciation.
Supporting Information Available: X-ray crystallographic files,
in CIF format, for the structure determinations of 1a, 1b, 2a, 2b, 3b,
4a, 4b, 5b, and 6a. This material is available free of charge via the
Internet at http://pubs.acs.org.
(38) Parkins, S.; Moezzi, B.; Hope, H. XABS2: An empirical absorption
corrections program. J. Appl. Crystallogr. 1995, 53-56.
(39) International Tables for X-ray Crystallography; Reidel: Boston, MA,
1992; Vol. C.
IC990885J