Coordination of Lewis acid to η2-enonepalladium(0) leading to continuous structure variation from η2-olefin type to η3-allyl type

Article abstract of DOI:10.1021/ja0036099

The reaction of α,β-unsaturated carbonyl compounds, a palladium(0) complex, and Lewis acids led to the formation of a new class of complexes showing a wide variety of structures with η²-type and η³-type coordination of the carbonyl compounds. The reaction of Pd(PhCH=CHCOCH₃)(PPh₃)₂ with BF₃·OEt₂ or B(C₆F₅)₃ quantitatively gave palladium complexes 1a,b having BX₃-coordinated η²-enonepalladium structure, as revealed by X-ray structure analysis of the B(C₆F₅)₃ adduct 1b. On the other hand, the reaction of Pd-(PhCH=CHCHO)(PPh₃)₂ with BF₃-OEt₂ or B(C₆F₅)₃ gave distorted zwitterionic η³-allylpalladium complexes 3a,b, where the Pd - carbonyl carbon distance in 3a (2.413(4) A) is much shorter than that (2.96(1) A) in 1b. The values of the P - P coupling constant and ¹³C chemical shift for carbonyl carbon are useful criteria for predicting how the η³-coordination mode contributes to the structure of the enone - palladium - Lewis acid system. Molecular orbital calculations on the series of model complexes suggest that orbital overlap in the highest occupied molecular orbital between the palladium and carbonyl carbon is enlarged by coordination of the Lewis acid to the carbonyl group. Palladium-catalyzed conjugate addition of R - M (R - M = AlMe₃ AlEt₃, ZnEt₂) and its plausible reaction path are also reported.

Full text of DOI:10.1021/ja0036099

1944
J. Am. Chem. Soc. 2001, 123, 1944-1950
Coordination of Lewis Acid to η2-Enonepalladium(0) Leading to
Continuous Structure Variation from η2-Olefin Type to η3-Allyl Type
Sensuke Ogoshi,* Tomohiro Yoshida, Takuma Nishida, Masaki Morita, and
Hideo Kurosawa*
Contribution from the Department of Applied Chemistry, Faculty of Engineering, Osaka UniVersity,
Suita, Osaka 565-0871, Japan
ReceiVed October 6, 2000
Abstract: The reaction of R,â-unsaturated carbonyl compounds, a palladium(0) complex, and Lewis acids led
to the formation of a new class of complexes showing a wide variety of structures with η2-type and η3-type
coordination of the carbonyl compounds. The reaction of Pd(PhCHdCHCOCH3)(PPh3)2 with BF3‚OEt2 or
B(C6F5)3 quantitatively gave palladium complexes 1a,b having BX3-coordinated η2-enonepalladium structure,
as revealed by X-ray structure analysis of the B(C6F5)3 adduct 1b. On the other hand, the reaction of Pd-
(PhCHdCHCHO)(PPh3)2 with BF3‚OEt2 or B(C6F5)3 gave distorted zwitterionic η3-allylpalladium complexes
3a,b, where the Pd-carbonyl carbon distance in 3a (2.413(4) Å) is much shorter than that (2.96(1) Å) in 1b.
The values of the P-P coupling constant and 13C chemical shift for carbonyl carbon are useful criteria for
predicting how the η3-coordination mode contributes to the structure of the enone-palladium-Lewis acid
system. Molecular orbital calculations on the series of model complexes suggest that orbital overlap in the
highest occupied molecular orbital between the palladium and carbonyl carbon is enlarged by coordination of
the Lewis acid to the carbonyl group. Palladium-catalyzed conjugate addition of R-M (R-M ) AlMe3, AlEt3,
ZnEt2) and its plausible reaction path are also reported.
Introduction
Scheme 1
The transition metal-catalyzed conjugate addition of various
organometallic reagents, e.g., AlR3, ZnR2, Cp2ZrRCl, InR3, and
BR3, to R,â-unsaturated carbonyl compounds is a very funda-
mental and useful reaction in organic synthesis.1 However, little
is known about its reaction course except for a vague recognition
that a key role is played by a Lewis acid at some stage of the
reaction, where the source of the acid can be the organometallic
reagents themselves or an intentionally added promoter. Some
related but scattered information led us to propose a general
scheme in which Lewis acids coordinate first to oxygen of the
enone ligand which is η2-bound to metal (Scheme 1). The η2-
bound complex then undergoes intramolecular rearrangement
to the η3-allyl intermediate which accompanies oxidation of the
metal atom. For example, in the nickel-catalyzed conjugate
addition of alkenyltin using chlorosilane as a promoter, η3-1-
(siloxy)allylnickel(II) chloride was isolated as the key interme-
diate,2 but it remains unclear what was the precursor of the η3-
allyl complex. Theoretical studies on the conjugate addition of
lithium organocuprate suggested that initial lithium cation
coordination to oxygen of the η2-enonecopper(I) complex
triggers the transformation.3 Our aim was to experimentally
demonstrate the existence of a range of structures from the Lewis
acid-coordinated η2-enone complex to the distorted η3-allyl
(Scheme 1) to gain a deeper insight into the role of Lewis acids
in transition metal-catalyzed conjugate addition. For this
purpose, we chose a palladium system, since prior knowledge
about the η3-allylpalladium complexes would help us to
characterize this class of variable structural complexes. More-
over, the observation of the stoichiometric reactions would allow
us to construct the mechanism of the palladium-catalyzed
conjugate addition of alkylmetals.
(1) Al: (a) Bagnell, L.; Jeffery, E. A.; Meisters, A.; Mole, T. Aust. J.
Chem. 1975, 28, 801. (b) Hansen, R. T.; Carr, D. B.; Schwartz, J. J. Am.
Chem. Soc. 1978, 100, 2244. (c) Schwartz, J.; Carr, D. B.; Hansen, R. T.;
Dayrit, F, M. J. Am. Chem. Soc. 1980, 102, 3053. Zr: (d) Schwartz, J.;
Loots, M. J.; Kosugi, H. J. Am. Chem. Soc. 1980, 102, 1333. (e) Hanzawa,
Y.; Tabuchi, N.; Taguchi, T. Tetrahedron Lett. 1998, 39, 8141. Zn: (f)
Greene, A. E.; Lansard, J.-P.; Luche, J.-L.; Petrier, C. J. Org. Chem. 1984,
49, 931. (g) Soai, K.; Hayasaka, T.; Ugajin, S. J. Chem. Soc., Chem.
Commun. 1989, 516. (h) Ikeda, S.-i.; Yamamoto, H.; Kondo, K.; Sato, Y.
Organometallics 1995, 14, 5015. In: (i) Pe´rez, I., Sestelo, J. P.; Maestro,
M. A.; Sarandeses, L. A. J. Org. Chem. 1998, 63, 10074. B: (j) Cho, C.
S.; Motofusa, S.-i.; Ohe, K.; Uemura, S. J. Org. Chem. 1995, 60, 883. (k)
Takaya, Y.; Ogasawara, M.; Hayashi, T.; Sakai, M.; Miyaura, N. J. Am.
Chem. Soc. 1998, 120, 5579.
Results and Discussion
Synthesis and Structures. The reaction of the enone complex
Pd(RCHdCHCOCH3)(PPh3)2 with BF3‚OEt2 or B(C6F5)3 gave
palladium complexes (R ) Ph: 1a, 1b. R ) H: 2a, 2b)
quantitatively, having the expected composition in the elemental
analysis (eq 1). The X-ray structure analysis of 1b shows a
(2) Johnson, J. R.; Tully, P. S.; Mackenzie, P. B.; Sabat, M. J. Am.
Chem. Soc. 1991, 113, 6172. Grisso, B. A.; Johnson, J. R.; Mackenzie, P.
M. J. Am. Chem. Soc. 1992, 114, 5160.
(3) Nakamura, E.; Yamanaka, M. J. Am. Chem. Soc. 1999, 121, 8941.
Nakamura, E.; Mori, S.; Morokuma, K. J. Am. Chem. Soc. 1997, 119, 4900.
10.1021/ja0036099 CCC: $20.00 © 2001 American Chemical Society
Published on Web 02/06/2001

Coordination of Lewis Acid to η2-Enonepalladium(0)
J. Am. Chem. Soc., Vol. 123, No. 9, 2001 1945
B(C6F5)3-coordinated η2-enonepalladium structure (Figure 1),
in which the Pd-C3 distance (2.96(1) Å) is very close to the
corresponding distance (2.91(2) Å) in the acid-free η2-enone
complex Pt(PhCHdCHCOCH3)(PPh3)2.4 The η2-enone bonding
in 1a, 2a, and 2b is deduced from NMR data, as will be
discussed later. On the other hand, the reaction of the enal
complex Pd(PhCHdCHCHO)(PPh3)2 with BF3‚OEt2 gave a
zwitterionic distorted η3-allylpalladium complex (3a), in which
the Pd-C3 distance (2.413(4) Å) is much shorter than that (2.89-
(2) Å) in Pt(PhCHdCHCHO)(PPh3)2 (eq 2, Figure 2).4 The
Figure 1. X-ray structure of 1b. Selected bond lengths: Pd-C1 )
2.11(1) Å, Pd-C2 ) 2.18(1) Å, Pd-C3 ) 2.96(1) Å, C1-C2 ) 1.45-
(2) Å, C2-C3 ) 1.41(2) Å, C3-O ) 1.32(1) Å.
Figure 2. X-ray structure of 3a. Selected bond lengths: Pd-C1 )
2.226(4) Å, Pd-C2 ) 2.161(4) Å, Pd-C3 ) 2.413(4) Å, C1-C2 )
1.416(5) Å, C2-C3 ) 1.390(5) Å, C3-O ) 1.309(5) Å.
structure of 3a represents another example of a distorted η3-
allylpalladium complex,5 which is receiving increasing interest
as a key structure in regioselective nucleophilic attack at η3-
allylpalladiums. The reaction of Pd(PhCHdCHCHO)(PPh3)2
with B(C6F5)3 gave the complex as a mixture of two isomers
in solution (3b/3b′ ) 26/1) (eq 3). NOE measurements on the
Figure 3. X-ray structure of 3b′. Selected bond lengths: Pd-C1 )
2.10(1) Å, Pd-C2 ) 2.117(1) Å, Pd-C3 ) 2.65(1) Å, C1-C2 ) 1.42-
(2) Å, C2-C3 ) 1.34(2) Å, C3-O ) 1.31(2) Å.
Scheme 2
major isomer 3b show a strong interaction between Ha and Hb,
as indicated in eq 3. The η3-allyl bonding in 3b is deduced from
NMR data, as will also be discussed later. However, the X-ray
structure analysis of single crystals obtained from a solution of
the mixture shows a B(C6F5)3-coordinated η2-enonepalladium
structure with s-trans configuration, 3b′ (Figure 3), which might
correspond to the minor isomer in solution. It is of further
interest that complexes 4a and 4b prepared from the reaction
of Pd(CH2dCHCHO)(PPh3)2 with BF3‚OEt2 and B(C6F5)3 have
a structure intermediate between those of the η2-type and the
η3-type complexes. The Pd-C3 distances in 4a and 4b are 2.59-
(1) and 2.596(5) Å respectively.
distance decreases (torsion angle (deg) for 1b, 98(1)° > 4b,
80.9(4)° > 4a, 77.8(9)° > 3a, 71.4(3)°).7 Thus, the structural
change from η2 to η3 can be viewed as the rotation of the triangle
defined by C1, C2, and C3 about the C1-C2 bond (Scheme
2).
The degree of the contribution of the η3-coordination mode
to the structure in solution could also be evaluated from the
13C and 31P NMR data. The Pd-C3 distance, 13C chemical shift
for carbonyl carbon, and P-P coupling constant for the
complexes derived from the addition of BF3‚OEt2 or B(C6F5)3
to the enone complexes are summarized in Table 1. The
In all those complexes analyzed crystallographically (1b, 3a,
4a, 4b), Pd, C1, C2, P1, and P2 are on the same plane,6 and the
torsion angle (Pd-C1-C2-C3) decreases as the Pd-C3
(4) Chaloner, P. A.; Davies, S. E.; Hitchcock, P. B. Polyhedron 1997,
16, 765.
(5) Togni, A.; Burckhardt, U.; Gramlich, V.; Pregosin, P. S.; Salzman,
R. J. Am. Chem. Soc. 1996, 118, 1031. Burckhardt, U.; Gramlich, V.;
Hofmann, P.; Nesper, R.; Pregosin, P. S.; Salzmann, R.; Togni, A.
Organometallics 1996, 15, 3496.
(7) Compared with the torsion angle (Pd-C1-C2-C3) and the Pd-
C3 distance, other parameters including bond length (Pd-C1, Pd-C2, C1-
C2, C2-C3, C3-O, O-B) and torsion angle (C2-C3-O-B) did not
change so remarkably.
(6) The sum of the bond angles (deg) around Pd along the P1, P2, C1,
and C2 atoms: 1b, 361.1; 3a, 359.7; 4a, 359.9; 4b, 358.3.

1946 J. Am. Chem. Soc., Vol. 123, No. 9, 2001
Ogoshi et al.
Table 1
Scheme 3
a
a
Pd-C3 (Å)
δ(CO)
J(P-P)
1a
1b
2a
2b
3a
3b
4a
4b
191.5
198.7
187.2
198.2
157.6
166.0
161.5
169.7
24.4
18.4
19.5
15.3
37.4
30.5
29.4
25.7
2.96(1)
2.413(4)
2.59(1)
2.596(5)
a In C6D6.
Table 2
Scheme 4
a
a
AIX3
AlCl3
AlMeCl3
AlMe2Cl
AlMe3
Pd-C3 (Å)
δ(CO)
J(P-P)
1c
1d
1e
1f
2.61(1)
2.649(6)
2.69(1)
182.1
188.1
193.8
31.8
26.9
20.8
13.5
a In C6D6.
Scheme 5
chemical shift of the carbonyl carbon at the higher magnetic
field is correlated with the shorter Pd-C3 distance. A similar
trend has been predicted by calculation for the cuprate-enone
system.3 Moreover, the complex having the shorter Pd-C3
distance shows a P-P coupling constant closer to that (46.5
Hz) for [(η3-PhCHCHCH2)Pd(PPh3)2]+. Thus, both values of
the P-P coupling constant and 13C chemical shift for carbonyl
carbon could be useful criteria for predicting how the η3-
coordination mode contributes to the structure of the palladium-
acid system. According to the criteria, the structure of the
complexes without the X-ray structure analysis was classified
as shown in eqs 1 and 3.
JPP (6a, 54.4 Hz; 6b, 51.4 Hz) of the complex derived from
enal is again larger than that in the complex derived from enone
(5a, 45.9 Hz; 5b, 41.9 Hz).
Similar treatment of Pd(PhCHdCHCOCH3)(PPh3)2 with a
series of aluminum compounds also led to the quantitative
formation of the corresponding complexes 1c-f, where the
structures of 1c-e were also determined. In this series, the
criteria mentioned above can be applied as well (eq 4, Table
2). The orders of the upfield shifts of the carbonyl carbon
MO Calculation of the Model Complexes. To understand
how the coordination of Lewis acids contributes to changing
the coordination mode of enone ligand, B3LYP geometry
optimizations were performed on model complexes, i.e., η2-
acrolein complex I and BF3 coordination complex II (Scheme
4). Palladium-carbon distances in the optimized geometry of
II (Pd-C1 2.195 Å, Pd-C2 2.233 Å, Pd-C3 2.594 Å) show
nice correlation to the experimental data (4a, Pd-C1 2.094(9)
Å, Pd-C2 2.151(9) Å, Pd-C3 2.59(1) Å; 4b, Pd-C1 2.161(5)
Å, Pd-C2 2.145(5) Å, Pd-C3 2.596(5) Å). For comparison,
in I, Pd-C1, Pd-C2, and Pd-C3 are 2.167, 2.203, and 2.946
Å, respectively. The calculations also showed that the atoms
Pd, C1, C2, P1 and P2 are on the same plane.8 From these
results, it may reasonably be concluded that the B3LYP
optimization can reproduce well the characteristic features of
the bonding interaction between enone ligand, Lewis acid, and
Pd(PH3)2.
Ab initio MO/MP2 calculations were performed on the
optimized geometry of I and II (Scheme 5). The highest
occupied molecular orbital (HOMO) of I shows no interaction
between dxy and px of carbonyl carbon. On the other hand,
coordination of BF3 enlarges the contribution of px on the
carbonyl carbon in the HOMO of II to increase the interaction
between Pd dxy and carbonyl carbon, which shortens the Pd-
C3 distance due to the electron donation (back-donation) from
Pd to carbonyl carbon. In other words, more positive carbonyl
carbon shortens the Pd-C3 distance and increases the oxidation
resonances and the P-P coupling constants are the same as that
of the Lewis acidity (1c > 1d > 1e > 1f), which indicates that
stronger Lewis acid induces the η3-allyl structure to a greater
extent. This is consistent with the small but steady decrease of
the Pd-C3 distance in the order 1c < 1d < 1e.
Similarly, 1,1′-bis(diphenylphosphino)ferrocene (DPPF)-
coordinated complexes were also prepared (Scheme 3). Reaction
of the (PhCHdCHCOCH3)Pd(dppf) complex with BF3, B(C6F5)3,
and AlCl3 gave the corresponding complexes, 5a-c. X-ray
structure analyses on 5b and 5c indicate that each Pd-C3
distance (2.875(5), 2.56(2) Å) is slightly shorter than that in
the corresponding bistriphenylphosphine complex (1b and 1c),
respectively. More importantly, AlCl3 makes a greater contribu-
tion to the η3-allyl form than B(C6F5)3 (compare 5c vs 5b, and
1c vs 1b). The reaction of (PhCHdCHCHO)Pd(dppf) with BF3
or B(C6F5)3 also gave the corresponding complexes 6a,b, where
(8) The sums of the bond angles (deg) around Pd along P1, P2 C1, and
C2 atoms are, for I, 360.0, and for II, 360.6.

Coordination of Lewis Acid to η2-Enonepalladium(0)
J. Am. Chem. Soc., Vol. 123, No. 9, 2001 1947
Scheme 6. A Plausible Mechanism
state of Pd more. In fact, natural bond orbital (NBO) population
analysis indicates that the Pd atomic charge in model complex
II (0.237) is more positive than that in I (0.120) and approaches
that in [(η3-allyl)Pd(PH3)2]+ (0.307).9 Such a greater positive
charge of palladium in II due to the coordination of a Lewis
acid has a significant implication in considering the transmeta-
lation step for the conjugate addition, as will be discussed in
more detail below. Moreover, this idea nicely accounts for the
observations described above: (1) the Pd-C3 distance in 1b is
longer than that in 3a, since the positive charge in 1b could be
delocalized by the attached CH3 group; (2) there is a steady
decrease of the Pd-C3 distance in the order 1c < 1d < 1e,
since a stronger Lewis acid can generate a larger positive charge
on the carbonyl carbon.
Stoichiometric Reaction with NaBPh4. In the palladium-
catalyzed addition of organozirconium1e and organoboron1g to
enones, Lewis acids including BF3 are indispensable to promote
conjugate additions. The adducts made from acids and enone
palladium complexes, possibly having an enhanced susceptibility
of Pd atom to transmetalation, seem to be intermediates in Lewis
acid-promoted palladium-catalyzed conjugate addition. Indeed,
we found that 1a reacted with NaBPh4 slowly to give the
conjugate addition product (eq 5), while neither Pd(PhCHd
CHCOCH3)(PPh3)2 (without BF3) nor PhCHdCHCOCH3/BF3
(without Pd) reacted with NaBPh4, which is also consistent with
the results of the MO calculation.
7). Both AlEt3 and ZnEt2 also underwent conjugate addition
under similar conditions.9 When Pd(PPh3)2 generated from Pd2-
(dba)3 and 4 equiv of PPh3 was employed as a catalyst, no
conjugate addition product was detected under the same
conditions.
Catalytic Conjugate Addition of Methylaluminum Com-
pounds. The complex 1f underwent slow decomposition to give
the conjugate addition compound PhCH(CH3)CH2COCH3 (18
h, 26%) in benzene, probably through an η3-allyl(methyl)-
palladium intermediate (eq 6).10 Although this result suggests
A possible reaction path is depicted in Scheme 6 (L ) solvent
or olefins). Coordination of AlMe3 leads to formation of the
intermediate B, similar to 1f, followed by transmetalation to
give the η3-allyl(methyl)palladium intermediate D. Reductive
elimination from D and subsequent coordination of enone and
L regenerate the η2-enone complex A.
Conclusion
a possibility of catalytic conjugate addition of PhCHd
CHCOCH3 with AlMe3, the noncatalytic reaction involving
these two, which gives rise to the 1,2-addition product PhCHd
CHCOH(CH3)2 predominantly, was much faster (2 h, 50%) than
the catalytic conjugate addition in benzene. Thus, suppression
of the 1,2-addition and acceleration of the conjugate addition
are required. To suppress the 1,2-addtion, the reaction was
carried out in THF, in which the 1,2-addition of AlMe3 did not
occur.1a The spectral observation of 1f having a considerable
lifetime suggests that the generation of the η3-allyl(methyl)-
palladium intermediate from 1f by transmetalation is slow,
possibly due to coordination of two PPh3 ligands. Thus, to make
the transmetalation more feasible, we employed Pd(PPh3) as a
catalyst, which was generated from Pd2(dba)3 and 2 equiv of
PPh3 in situ. With this catalyst system, the conjugate addition
of AlMe3 to PhCHdCHCOCH3 in THF at room temperature
occurred quantitatively to give the corresponding product (eq
We demonstrated the formation of a new class of complexes
showing a wide variety of structures with η2-type and η3-type
coordination of the R,â-unsaturated compounds, starting from
palladium(0) complex and Lewis acids. Proposed criteria for
estimation of the degree of the contribution of the η3-coordina-
tion mode to the structure are consistent with the results of the
X-ray structure analyses. MO calculation on the set of the model
complexes reveals why Lewis acids increase the contribution
of the η3-coordination mode to the η2-enone complex. Moreover,
these observations are applied to the construction of the
palladium-catalyzed catalytic conjugate addition of the alkyl-
metals. In principle, this method could be widely applicable to
numerous combinations of unsaturated compounds, low-valent
transition metals, and Lewis acids.
Experimental Section
General. All manipulations were conducted under a nitrogen
atmosphere using standard Schlenk or drybox techniques. 1H, 31P, and
13C nuclear magnetic resonance spectra were recorded on JEOL GSX-
270S and JEOL AL-400 spectrometers. Elemental analyses were
performed at the Instrumental Analysis Center, Faculty of Engineering,
Osaka University. For some compounds, accurate elemental analyses
(9) Sakaki, S.; Takeuchi, K.; Sugimoto, M.; Kurosawa, H. Organome-
tallics 1997, 16, 2995. Kurosawa, H.; Hirako, K.; Natsume, S.; Ogoshi, S.;
Kanehisa, N.; Kai, Y.; Sakaki, S.; Takeuchi, K. Organometallics 1996, 15,
2089.
(10) Palladium-catalyzed conjugate addition of AlR3 or ZnR2 has not
been reported yet.

1948 J. Am. Chem. Soc., Vol. 123, No. 9, 2001
Ogoshi et al.
JHH ) 9.5 Hz, JHP ) 2.4, 6.5 Hz, 1H), 5.07 (ddd, JHH ) 9.5 Hz, JHP
5.3, 8.8 Hz, 1H), 6.60 (d, JHH ) 6.5 Hz, 2H), 6.93 (m, 21H), 7.16 (m,
6H), 7.32-7.37 (m, 6H). 31P NMR (C6D6): δ 24.59 (d, JPP ) 13.5
Hz), 28.58 (d, JPP ) 13.5 Hz).
were precluded by extreme air or thermal sensitivity and/or systematic
problems with elemental analysis of organometallic compounds.11
Materials. Unless indicated otherwise, solvents and reagents were
purchased from commercial vendors, distilled, and degassed prior to
use. B(C6F5)3 (3.9 wt % PF-3/Isoper E solution) was donated by Asahi
Glass Co. Tetrahydrofuran, benzene, and hexane were purified by
distillation from sodium benzophenone ketyl. Celite filtrations were
performed by using a plug of Hyflo Super Gel (Wako) over glass wool
in disposal pipets or alone on glass filters under vacuum.
)
(CH2CHCCH3(OBF3))Pd(PPh3)2 (2a). To a solution of Pd(CH2d
CHCOCH3)(PPh3)2 (100.4 mg, 0.143 mmol) in 5 mL of THF was added
18.0 µL of BF3‚OEt2 (16.1 mg, 0.142 mmol) at room temperature. The
reaction mixture was concentrated in vacuo to give yellow solids
quantitatively. The solids were washed with hexane and recrystallized
1
(PhCHCHCCH3(OBF3))Pd(PPh3)2 (1a). To a solution of Pd-
(PhCHdCHCOCH3)(PPh3)2 (116.0 mg, 0.149 mmol) in 5 mL of THF
was added 18.9 µL of BF3‚OEt2 (21.1 mg, 0.149 mmol) at room
temperature, and the solution changed from yellow to red. The reaction
mixture was concentrated in vacuo to give orange solids (1a)
quantitatively. The solids were washed with hexane to give 117.3 mg
of 1a in 93% isolated yield. An analytical sample was prepared by
from THF/hexane solution to give orange solids (60.1 mg, 55%). H
NMR (C6D6): δ 1.63 (d, JHP ) 8.4 Hz, 3H), 2.29 (dt, JHH ) 2.6, 10.2
Hz, JHP ) 7.6 Hz, 1H), 3.55 (dddd, JHH ) 2.6, 7.5 Hz, JHP ) 4.9, 11.1
Hz, 1H), 3.97 (ddd, JHH ) 7.5, 10.2 Hz, JHP ) 7.7 Hz, 2H), 6.90-7.41
(m, 30H). 31P NMR (C6D6): δ 22.92 (d, JPP ) 19.5 Hz), 36.02 (d, JPP
) 19.5 Hz). 13C NMR (CDCl3): δ(CO) 187.2. Anal. Calcd for C40H36-
BF3OP2Pd: C, 62.48; H, 4.72. Found: C, 62.73; H, 4.88.
1
recrystallization from THF/hexane solution. H NMR (C6D6): δ 1.73
(CH2CHCCH3(OB(C6F5)3)Pd(PPh3)2 (2b). To a solution of Pd-
(CH2dCHCOCH3)(PPh3)2 (195.3 mg, 0.278 mmol) in 5 mL of THF
was added 5.0 mL of B(C6F5)3 (142.0 mg, 0.277 mmol) at room
temperature, and the solution changed from yellow to orange. The
reaction mixture was concentrated in vacuo to give yellow solids
quantitatively. The solids were washed with hexane and recrystallized
from THF/hexane solution to give yellow solids (187.9 mg, 56%). 1H
NMR (C6D6): δ 1.12 (d, JHP ) 8.8 Hz, 3H), 2.41 (ddd, JHH ) 3.0, 10.2
Hz, JHP ) 7.7 Hz, 1H), 3.45 (ddd, JHH ) 3.0, 6.7 Hz, JHP ) 10.8 Hz,
1H), 4.11 (ddd, JHH ) 6.7, 10.2 Hz, JHP ) 6.5 Hz, 1H), 6.78-7.20 (m,
(d, JHP ) 6.8 Hz, 3H), 4.47 (ddd, JHH ) 9.7 Hz, JHP ) 1.8, 6.2 Hz,
1H), 4.98 (ddd, JHH ) 9.7 Hz, JHP ) 4.3, 9.5 Hz, 1H), 6.66 (JHH ) 7.6
Hz, 2H), 6.84-6.91 (m, 21H), 7.19-7.21 (m, 6H), 7.37-7.47 (m, 6H).
31P NMR (C6D6): δ 24.72 (d, JPP ) 24.4 Hz), 30.64 (d, JPP ) 24.4
Hz). 13C NMR (C6D6): δ(CO) 191.5. Anal. Calcd for C46H40BF3OP2Pd:
C, 65.39; H, 4.77. Found: C, 65.83; H, 4.91.
1
(PhCHCHCCH3(OB(C6F5)3)Pd(PPh3)2 (1b). H NMR (C6D6): δ
1.39 (d, JHP ) 6.8 Hz, 3H), 4.66 (ddd, JHH ) 10.4 Hz, JHP ) 2.1, 5.7
Hz, 1H), 5.06 (ddd, JHH ) 10.4 Hz, JHP ) 3.6, 8.3 Hz, 1H), 6.63 (d,
JHH ) 6.5 Hz 2H), 6.79-7.01 (m, 6H), 7.18-7.21 (m, 6H). 31P NMR
(C6D6): δ 24.07 (d, JPP ) 18.4 Hz), 29.53 (d, JPP ) 18.4 Hz). 13C NMR
(C6D6): δ(CO) 198.7. Anal. Calcd for C46H40BF15OP2Pd: C, 59.63; H,
3.13. Found: C, 59.39; H, 3.44. X-ray data for 1b: M ) 1332.24,
triclinic, space group P1h, a ) 13.4848(6) Å, b ) 19.7981(7) Å, c )
12.5442(6) Å, R ) 95.005(5)°, â ) 108.253(4)°, γ ) 104.492(2)°, V
) 3028.9(2) Å3, Dcalcd ) 1.461 g/cm3, Z ) 2, T ) 23.0 °C, R (Rw) )
0.086 (0.117).
30H). 31P NMR (C6D6): δ 23.64 (d, JPP ) 15.3 Hz), 34.24 (d, JPP
)
15.3 Hz).13C NMR (C6D6): δ(CO) 198.2. Anal. Calcd for C58H36BF15-
OP2Pd: C, 57.43; H, 2.99. Found: C, 57.67; H, 3.27.
(PhCHCHCH(OBF3))Pd(PPh3)2 (3a). 1H NMR (C6D6): δ 4.63
(ddd, JHH ) 3.3, 10.9 Hz, JHP ) 3.3 Hz, 1H), 5.01 (ddd, JHH ) 10.9
Hz, JHP ) 2.9, 10.9 Hz, 1H), 6.53 (d, JHH ) 7.2 Hz, 2H), 6.79-6.95
(m, 21H), 7.04-7.10 (m, 6H), 7.45-7.50 (m, 6H), 7.88 (dd, JHH
)
3.3 Hz, JHP ) 5.2 Hz, 1H). 31P NMR (C6D6): δ 24.41 (d, JPP ) 37.4
Hz), 29.01 (d, JPP ) 37.4 Hz). 13C NMR (C6D6): δ(CO) 157.6. Anal.
Calcd for C45H38BF3OP2Pd: C, 65.04; H, 4.61. Found: C, 64.65; H,
4.82. X-ray data for 3a‚THF: M ) 891.04, triclinic, space group P1h,
a ) 17.952(10) Å, b ) 18.473(4) Å, c ) 12. 912(2) Å, R ) 89.89(2)°,
â ) 89.99(3)°, γ ) 90.46(3)°, V ) 4283(2) Å3, Dcalcd ) 1.382 g/cm3,
Z ) 4, T ) 15.0 °C, R (Rw) ) 0.083 (0.116).
(PhCHCHCCH3(OAlCl3))Pd(PPh3)2 (1c). 1H NMR (C6D6): δ 1.52
(dd, JHP ) 2.8, 8.4 Hz, 3H), 4.44 (dd, JHH ) 10.8 Hz, JHP ) 4.3 Hz,
1H), 4.99 (ddd, JHH ) 10.8 Hz, JHP ) 2.7, 9.7 Hz, 1H), 6.55 (d, JHH
)
7.2 Hz, 2H), 6.85-7.01 (m, 21H), 7.13-7.16 (m, 6H), 7.27-7.31 (m,
6H). 31P NMR (C6D6): δ 23.49 (d, JPP ) 31.8 Hz), 30.25 (d, JPP
)
31.8 Hz). 13C NMR (C6D6): δ(CO) 182.1. X-ray data for 1c‚THF: M )
982.62, orange, monoclinic, P21/n, a ) 18.1758(3) Å, b ) 12.1664(3)
Å, c ) 21.8447(1) Å, â ) 93.679(2)°, V ) 4820.7(1) Å, Z ) 4, Dcalcd
) 1.354 g/cm3, T ) 23.0 °C, R (Rw) ) 0.073 (0.108).
(PhCHCHCH(OB(C6F5)3)Pd(PPh3)2 (3b/3b′′ ) 26/1). 3b. 1H NMR
(C6D6): δ 4.92 (ddd, JHH ) 3.7, 10.8 Hz, JHP ) 3.7 Hz, 1H), 5.32
(ddd, JHH ) 10.8 Hz, JHP ) 1.8, 10.8 Hz, 1H), 6.55 (d, JHH ) 7.2 Hz,
2H), 6.72-6.89 (m, 6H), 6.90-6.92 (m, 12H), 6.99-7.06 (m, 12H),
7.69 (brs, 1H). 31P NMR (C6D6): δ 23.04 (d, JPP ) 30.5 Hz), 27.93 (d,
JPP ) 30.5 Hz). 13C NMR (C6D6): δ(CO) 166.0.
3b′. 1H NMR (C6D6): δ 3.72 (d, JHH ) 10.2 Hz, 1H), 5.56 (dd, JHH
) 10.8 Hz, JHP ) 10.8 Hz, 1H), 6.41 (d, JHH ) 7.2 Hz, 2H), 6.72 (t,
7.0 Hz, 3H), 8.02 (d, JHH ) 4.0 Hz, 1H). The other resonances are
hidden by those of the major isomer. Anal. Calcd for C63H38BF15OP2-
Pd: C, 59.34; H, 3.00. Found: C, 58.98; H, 3.37. X-ray data for 3b′‚
THF: M ) 1347.23, red, triclinic, P1h, a ) 14.2626(6) Å, b )
18.8457(9) Å, c ) 13.5537(2) Å, R ) 105.384(2)°, â ) 118.213(3)°,
γ ) 93.552(2)°, V ) 3019.0(2) Å3, Z ) 2, Dcalcd ) 1.482 g/cm3, T )
23.0 °C, R (Rw) ) 0.077 (0.112).
(PhCHCHCCH3(OAlMeCl2))Pd(PPh3)2 (1d). 1H NMR (C6D6): δ
0.15 (s, 3H), 1.58 (dd, JHP ) 2.4, 7.6 Hz, 3H), 4.49 (ddd, JHH ) 10.3
Hz, JHP ) 5.3, 1.4 Hz, 1H), 4.98 (ddd, JHH ) 10.3 Hz, JHP ) 3.6, 10.1
Hz, 1H), 6.57 (d, JHH ) 7.2 Hz, 2H), 6.87-7.00 (m, 21H), 7.15-7.31
(m, 6H), 7.32-7.35 (m, 6H). 31P NMR (C6D6): δ 24.69 (d, JPP ) 26.9
Hz), 30.72 (d, JPP ) 26.9 Hz). 13C NMR (C6D6): δ(CO) 188.1. X-ray
data for 1d‚THF: M ) 962.20, red, monoclinic, P21/n, a ) 18.245(2)
Å, b ) 12.104(1) Å, c ) 21.929(1) Å, â ) 94.015(1)°, V ) 4831.0(7)
Å3, Z ) 4, Dcalcd ) 1.323 g/cm3, T ) 23.0 °C, R (Rw) ) 0.070 (0.075).
1
(PhCHCHCCH3(OAlMe2Cl))Pd(PPh3)2 (1e). H NMR (C6D6): δ
0.02 (s, 3H), 0.06 (s, 3H), 1.59 (d, JHP ) 5.6 Hz, 3H), 4.52 (m, 1H),
5.00 (m, 1H), 6.59 (d, JHH ) 7.0 Hz, 2H), 6.94 (m, 21H), 7.16 (m,
6H), 7.35 (m, 6H). 31P NMR (C6D6): δ 24.07 (d, JPP ) 20.8 Hz), 29.28
(d, JPP ) 20.8 Hz). 13C NMR (C6D6): δ(CO) 193.8. X-ray data for 1e‚
THF: M ) 941.78, orange, monoclinic, P21/n, a ) 18.2637(3) Å, b )
12.0305(1) Å, c ) 22.0524(5) Å, â ) 93.639(2)°, V ) 4835.6(1) Å3,
Z ) 4, Dcalcd ) 1.294 g/cm3, T ) 23.0 °C, R (Rw) ) 0.082 (0.113).
(PhCHCHCCH3(OAlMe3))Pd(PPh3)2 (1f). To a solution of Pd-
(PhCHdCHCOCH3)(PPh3)2 (100.8 mg 0.13 mmol) in THF (5 mL) was
added 0.13 mL (1.01 M) of a solution of AlMe3 in hexane, and the
reaction mixture changed to orange. The reaction mixture was
concentrated, and the residue was washed with hexane to give yellow
solids quantitatively. Recrystalization failed due to the decomposition
(CH2CHCH(OBF3))Pd(PPh3)2 (4a). 1H NMR (C6D6): δ 2.60 (ddd,
JHH ) 2.9, 6.9 Hz, JHP ) 6.9 Hz, 1H), 3.46 (ddd, JHH ) 2.9, 10.2 Hz,
JHP ) 6.9 Hz, 1H), 4.07 (ddd, JHH ) 2.9, 6.9, 10.2 Hz, 1H), 7.00-
7.08 (m, 18H), 7.36-7.48 (m, 12H), 7.90 (dd, JHH ) 2.9 Hz, JHP
)
5.9 Hz, 1H). 31P NMR (C6D6): δ 21.70 (d, JPP ) 29.4 Hz), 34.68 (d,
JPP ) 29.4 Hz). 13C NMR (C6D6): δ(CO) 161.5. Anal. Calcd for C39H34-
BF3OP2Pd: C, 62.05; H, 4.54. Found: C, 61.67; H, 4.69. X-ray data
for 4a: M ) 754.85, yellow, monoclinic, P21/c, a ) 17.8836(3) Å, b )
11.4747(2) Å, c ) 18.263(1) Å, â ) 106.656(2)°, V ) 3590.5(2) Å3,
Z ) 4, Dcalcd ) 1.396 g/cm3, T ) 23.0 °C, R (Rw) ) 0.073 (0.074).
(CH2CHCH(OB(C6F5)3))Pd(PPh3)2 (4b). 1H NMR (C6D6): δ 2.72
(ddt, J ) 2.3, 7.5 Hz, JHP ) 6.1 Hz, 1H), 3.50 (ddt, J ) 2.3, 11.1 Hz,
JHP ) 8.5 Hz, 1H), 4.26 (ddd, J ) 3.8, 7.5, 11.1 Hz, 1H), 6.85-6.99
(m, 18H), 7.06-7.10 (m, 6H), 7.29-7.34 (m, 6H), 7.70 (d, J ) 3.8
Hz, JHP ) 5.6 Hz, 1H). 31P NMR (C6D6): δ 21.99 (d, JPP ) 25.7 Hz),
1
to give the corresponding conjugate addition product (18 h, 26%). H
NMR (C6D6): δ 0.03 (s, 9H), 1.52 (d, JHP ) 4.6 Hz, 3H), 4.55 (ddd,
(11) See the Supporting Information in the following: Carney, M. J.;
Walsh, P. J.; Bergman, R. G. J. Am. Chem. Soc. 1990, 112, 6426.

Coordination of Lewis Acid to η2-Enonepalladium(0)
J. Am. Chem. Soc., Vol. 123, No. 9, 2001 1949
33.10 (d, JPP ) 25.7 Hz). 13C NMR (C6D6): δ(CO) 169.7. Anal. Calcd
for C57H34BF15OP2Pd: C, 57.10; H, 2.86. Found: C, 57.12; H, 3.09.
Crystal data for 4b: M ) 1199.03, yellow, triclinic, P1h (No. 2), a )
14.555(3) Å, b ) 17.376(4) Å, c ) 10.860(4) Å, R ) 97.73(3)°, â )
103.05(2)°, γ ) 105.88(2)°, V ) 2516(1) Å3, Z ) 4, Dcalcd ) 3.164
g/cm3, T ) 23.0 °C, R (Rw) ) 0.045 (0.039).
Pd(PhCHdCHCHO)(dppf). To a solution of (η3-CH2CHCH2)PdCp
(201.3 mg, 0.942 mmol) and dppf (519.9 mg, 0.938 mmol) in 15 mL
of THF was added 0.12 mL of PhCHdCHCHO (125.8 mg, 0.952
mmol), the mixture was stirred for 2 h at room temperature, and the
solution changed from red to orange. The reaction mixture was
concentrated in vacuo and washed with hexane to give yellow solids
quantitatively (617.0 mg, 83%). 1H NMR (C6D6): δ 3.86 (m, 5H), 4.24
(m, 3H), 5.06 (m, 2H), 6.84-7.16 (m, 19H), 7.74 (m, 4H), 7.95 (m,
2H) 9.35 (d, JHH ) 5.4 Hz). 31P NMR (C6D6): δ 25.49 (s).
1
[(η3-PhCHCHCH2)Pd(PPh3)2][BF4]. H NMR (400 MHz, C6D6):
δ 3.64 (ddd, JHH ) 6.6, 0.5 Hz, JHP ) 6.6 Hz, 1H), 3.96 (ddd, JHH
)
11.5, 1.0 Hz, JHP ) 11.5 Hz, 1H), 5.85 (dddd, JHH ) 11.5, 1.0, 0.5 Hz,
JHP ) 11.9 Hz, 1H), 6.59 (m, 4H), 6.63 (m, 1H), 6.91-7.24 (m, 7H),
7.02 (m, 6H), 7.08 (m, 6H), 7.22 (m, 6H), 7.54 (m, 6H). 31P NMR
(109 MHz, C6D6): δ 25.43 (d, JPP ) 46.5 Hz), 27.07 (d, JPP ) 46.5
Hz). Anal. Calcd for C45H39BF4P2Pd: C, 64.73; H, 4.41. Found: C,
65.00; H, 4.73.
Pd(PhCHdCHCOCH3)(dppf). A solution of (η3-CH2CHCH2)PdCp
(202.0 mg, 0.946 mmol), PhCHdCOCH3 (136.9 mg, 0.936 mmol),
and DPPF (520.4 mg, 0.939 mmol) in 15 mL of THF was stirred for
2 h at room temperature. The reaction mixture was concentrated in
vacuo and washed with hexane to give yellow solids (629.6 mg, 83%).
1H NMR (C6D6): δ 1.76 (s, 3H), 3.78 (brs, 2H), 3.85 (brs, 1H), 3.96
(brs, 1H), 4.01 (brs, 1H), 4.08 (brs, 2H), 4.48 (brs, 1H), 5.01 (ddd, JHH
) 10.8 Hz, JHP ) 4.1, 7.3 Hz, 1H), 5.34 (dd, JHH ) 10.8 Hz, JHP ) 7.3
Hz, 1H), 6.88-7.22 (m, 19H), 7.64 (m, 2H), 7.86 (m, 4H). 31P NMR
(C6D6): δ 18.58 (s), 18.62 (s).
(PhCHCHCH(OBF3))Pd(dppf) (6a). To a solution of Pd(PhCHd
CHCHO)(dppf) (100.0 mg, 0.126 mmol) in 10 mL of THF was added
16.0 µL of BF3‚OEt2 (17.9 mg, 0.126 mmol) at room temperature, and
the solution changed from yellow to orange. The reaction mixture was
concentrated in vacuo to give yellow solids quantitatively. The solids
were washed with hexane and recrystallized from THF/hexane solution
1
to give yellow solids (20.7 mg, 19%). H NMR (C6D6): δ 3.58 (m,-
1H), 3.66 (m, 2H), 3.81 (m, 1H), 3.87 (m, 1H), 3.90 (m, 1H), 4.65 (m,
1H), 4.93 (m, 1H), 5.71 (m, 1H), 6.64 (m, 2H), 6.80-7.21 (m, 13H),
7.73 (m, 2H), 7.50 (m, 3H), 7.66 (m, 2H), 7.78 (m, 1H), 7.90 (m, 2H).
31P NMR (C6D6): δ 21.82 (d, JPP ) 54.4 Hz), 25.66 (d, JPP ) 54.4
Hz).
(PhCHCHCH(OB(C6F5)3)Pd(dppf) (6b). To a solution of Pd-
(PhCHdCHCHO)(dppf) (100.2 mg, 0.126 mmol) in 11 mL of THF
was added 2.3 mL of B(C6F5)3 (65.3 mg, 0.128 mmol) at room
temperature, and the solution changed from yellow to red. The reaction
mixture was concentrated in vacuo to give orange solids quantitatively.
The solids were washed with hexane and recrystallized from THF/
(PhCHCHCCH3(OBF3))Pd(dppf) (5a). To a solution of Pd(PhCHd
CHCOCH3)(dppf) (103.5 mg, 0.128 mmol) in 3 mL of THF was added
16.2 µL of BF3‚OEt2 (18.1 mg, 0.128 mmol) at room temperature, and
the solution changed from orange to red. The reaction mixture was
concentrated in vacuo to give yellow solids quantitatively. The solids
were washed with hexane and recrystallized from THF/hexane solution
1
hexane solution to give orange solids. H NMR (C6D6): δ 3.66 (brs,
3H), 3.81 (brs, 3H), 3.89 (brs, 2H), 4.06 (brs, 1H), 4.69 (brs, 1H), 4.93
(ddd, JHH ) 4.1, 11.3 Hz, JHP ) 4.1 Hz, 1H), 5.31 (dd, JHH ) 11.3 Hz,
JHP ) 11.3 Hz, 1H), 6.72-7.26 (m, 20H), 7.50 (m, 2H), 7.62 (m, 1H),
7.74 (m, 2H), 7.83 (brs, 1H). 31P NMR (C6D6): δ 20.61 (d, JPP ) 51.4
Hz), 27.65 (d, JPP ) 51.4 Hz). Anal. Calcd for C61H36BF15OP2FePd:
C, 56.15; H, 2.78. Found: C, 55.84; H, 3.06.
1
to give yellow solids (7.1 mg, 6%). H NMR (C6D6): δ 1.69 (dd, JHP
) 3.4, 8.2 Hz, 3H), 3.56 (brs, 2H), 3.66 (brs, 1H), 3.81 (m, 2H), 3.95
(brs, 1H), 4.25 (brs, 1H), 4.58 (dd, JHH ) 10.3 Hz, JHP ) 6.2 Hz, 1H),
4.77 (ddd, JHH ) 10.3 Hz, JHP ) 2.4, 9.7 Hz, 1H), 5.62 (brs, 1H), 6.69
(d, JHH ) 5.4 Hz, 2H), 6.73-7.08 (m, 15H), 7.35 (m, 2H), 7.55 (m,
Reaction of 1a with NaBPh4. 1a (15.6 mg, 0.0185 mmol) and
NaBPh4 (7.2 mg, 0.0210 mmol) were placed in a sealed NMR tube,
and C6D6 (0.6 mL) was added. The sample was heated at 80 °C and
2H), 7.70 (m, 2H), 7.92(m, 2H). 31P NMR (C6D6): δ 22.34 (d, JPP
45.9 Hz), 25.27 (d, JPP ) 45.9 Hz).
)
1
followed by H NMR. Selected spectral data for Ph2CHCH2COCH3
(PhCHCHCCH3(OB(C6F5)3)Pd(dppf) (5b). To a solution of Pd-
(PhCHdCHCOCH3)(dppf) (102.3 mg, 0.127 mmol) in 3 mL of THF
was added 2.2 mL of B(C6F5)3 (62.5 mg, 0.122 mmol) at room
temperature, and the solution changed from orange to red. The reaction
mixture was concentrated in vacuo to give orange solids quantitatively.
The solids were washed with hexane and recrystallized from THF/
hexane solution to give orange crystals (58.4 mg, 35%). 1H NMR
(C6D6): δ 1.17 (dd, JHP ) 1.9, 7.8 Hz, 3H), 3.61 (brs, 1H), 3.68 (brs,-
1H), 3.72 (brs, 1H), 3.77 (brs, 3H), 4.29 (brs, 1H), 4.81 (brs, 1H), 4.89
1
are given here. H NMR (C6D6): δ 1.55 (s, 3H), 2.69 (d, JHH ) 7.43
Hz, 2H), 4.62 (t, JHH ) 7.43 Hz, 1H).
MO Calculation. Molecular geometry optimization followed by
analytical frequency calculations was performed at the B3LYP/BS-1
(BS-1: Pd, valence electrons (5s 5p 4d)/[3s 3p 2d], core electrons ECPs
(up to 3d);12 P, valence electrons (3s 3p)/[2s 2p], core electrons ECPs
(up to 2p);13 others, 6-31G*) levels of theory using the Gaussian 94
programs.14 The ab initio MO/MP2 calculation using BS-2 (BS-2: Pd,
valence electrons (5s 5p 4d)/[3s 3p 2d], core electrons ECPs (up to
3d); others, 6-31G*) was carried out on the optimized geometry.
(brs, 1H), 4.89 (m, 2H), 6.78-7.03 (m, 20H), 7.58-7.74 (m, 5H). 31
P
NMR (C6D6): δ 20.78 (d, JPP ) 41.9 Hz), 25.80 (d, JPP ) 41.9 Hz).
Crystal data for 5b: M ) 1330.97, orange, triclinic, P1h (No. 2), a )
14.0407(8) Å, b ) 16.7253(8) Å, c ) 13.5783(9) Å, R ) 11.592(4)°,
Typical Procedure for Catalytic Reaction (Reaction with AlMe3).
Under a nitrogen atmosphere, to a solution of 146.2 mg of PhCHd
CHCOCH3 (1.0 mmol), 166.7 mg of n-nonadecane (internal standard),
and 13.1 mg of Pd2(dba)3‚CHCl3 in 5.0 mL of THF was added 1.0 mL
of a hexane solution of AlMe3 (1.01 Μ) at room temperature. The
reaction mixture was stirred for 0.5 h and then poured into 5 mL of 1
M HCl aqueous solution. The organic layer was extracted with three
potions of 3 mL of Et2O. The yield was determined by GC. PhCH-
(CH3)CHCOCH3 was obtained quantitatively.
â ) 112.023(2)°, γ ) 76.314(3)°, V ) 2730.5(3) Å3, Z ) 2, Dcalcd
1.619 g/cm3, T ) 23.0 °C, R (Rw) ) 0.066 (0.076).
)
(PhCHCHCCH3(OAlCl3))Pd(dppf) (5c). To a solution of Pd-
(PhCHdCHCOCH3)(dppf) (151.6 mg, 0.188 mmol) in 3 mL of THF
was added AlCl3 (26.1 mg, 0.196 mmol) at room temperature, and the
solution changed from orange to red. The reaction mixture was
concentrated in vacuo to give yellow solids quantitatively. The solids
were washed with hexane and recrystallized from THF/hexane solution
Reaction with AlEt3. Ten mol % of Pd(PPh3) was employed.
PhCH(CH2CH3)CHCOCH3 was obtained in 72% yield.
1
to give red crystals (50.1 mg, 28%). H NMR (C6D6): δ 1.51 (dd, JHP
) 4.1, 9.2 Hz, 3H), 3.56 (d, JHH ) 6.8 H, 1H), 3.81 (d, JHH ) 6.2 H,
1H), 4.04 (brs, 1H), 4.35 (brs, 1H), 4.58 (m, 1H), 4.77 (m, 1H), 5.07
(brs, 1H), 6.46 (d, JHH ) 7.5 Hz, 2H), 6.54-7.03 (m, 12H), 7.11-
7.25 (m, 4H), 7.37-7.45 (m, 4H), 7.55-7.72 (m, 3H). 31P NMR (C6D6):
δ 21.28 (d, JPP ) 51.1 Hz), 25.88 (d, JPP ) 51.1 Hz). Anal. Calcd for
C44H38AlCl3OP2FePd: C, 56.20; H, 4.07. Found: C, 55.52; H, 4.51.
Crystal data for 5c‚THF: M ) 1012.43, red, triclinic, P1h (No. 2), a )
17.890(2) Å, b ) 221.853(2) Å, c ) 12.076(1) Å, R ) 90.103(2)°, â
) 90.145(1)°, γ ) 93.822(3)°, V ) 4710.6(8) Å3, Z ) 5, Dcalcd ) 1.784
g/cm3, T ) 23.0 °C, R (Rw) ) 0.088 (0.129).
(12) Hay. P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 299.
(13) Wadt, W. R.; Hay, P. J. J. Chem. Phys. 1985, 82, 284.
(14) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Gill, P. M. W.;
Johnson, B. G.; Robb, M. A.; Cheeseman, J. R.; Keith, T. A.; Petersson,
G. A.; Montgomery, J. A.; Raghavachari, K.; Al-Laham, M. A.; Zakrzewski,
V. G.; Oritiz, J. V.; Foresman, J. B.; Cioslowski, J.; Stefanov, B. B.;
Nanayakkara, A.; Chalacombe, M.; Peng, C. Y.; Ayala, P. Y.; Chen, W.;
Wong, M. W.; Andres, J. L.; Replogle, E. S.; Gomperts, R.; Martin, R. L.;
Fox, D. J.; Binkley, J. S.; Defrees, D. J.; Baker, J.; Stewart, J. P.; Head-
Gordon, M.; Gonzalez, C.; People, J. A. Gaussian 94; Gaussian, Inc.:
Pittsburgh, PA, 1995.

1950 J. Am. Chem. Soc., Vol. 123, No. 9, 2001
Ogoshi et al.
Reaction with ZnEt2. Ten mol % of Pd(PPh3) was employed, and
the reaction mixture was stirred for 1 h. PhCH(CH2CH3)CHCOCH3
was obtained in 93% yield.
Supporting Information Available: Details of crystal-
lographic analyses for 1b-e, 3a, 3b′, 4a, 4b, 5b, and 5c;
complete tables of atomic coordinates and selected bond
distances and angles for the compounds listed above (PDF).
This material is available free of charge via the Internet at
http://pubs.acs.org.
Acknowledgment. Partial support of this work through
CREST of the Japan Science and Technology Corporation and
Grants-in-Aid for Scientific Research from the Ministry of
Education, Science and Culture, Japan, is gratefully acknowl-
edged. We also acknowledge Asahi Glass Co. for the donation
of B(C6F5)3.
JA0036099