Preparation and NMR spectroscopy of (1,2-bis(diphenylphosphino)ethane)(η3-1,3-diarylallyl)-palladium tetrafluoroborates. Correlation of chemical shifts with Hammett substituent constants and with the regioselectivity of nucleophilic attack

Article abstract of DOI:10.1021/om9605591

¹³C NMR chemical shifts of the terminal allyl carbon atoms C-1 and C-3 of (1,2-bis-(diphenylphosphino)ethane)(η³-1,3-diarylallyl)palladium tetrafluoroborates correlate with σ Hammett substituent constants. For each complex the chemic

Full text of DOI:10.1021/om9605591

Organometallics 1997, 16, 205-209
205
P r ep a r a tion a n d NMR Sp ectr oscop y of
(1,2-Bis(d ip h en ylp h osp h in o)eth a n e)(η3-1,3-d ia r yla llyl)-
p a lla d iu m Tetr a flu or obor a tes. Cor r ela tion of Ch em ica l
Sh ifts w ith Ha m m ett Su bstitu en t Con sta n ts a n d w ith th e
Regioselectivity of Nu cleop h ilic Atta ck
Marcial Moreno-Man˜as,* Francesca Pajuelo, Teodor Parella, and Roser Pleixats
Department of Chemistry, Universitat Auto`noma de Barcelona, Bellaterra,
08193-Barcelona, Spain
Received J uly 8, 1996X
13C NMR chemical shifts of the terminal allyl carbon atoms C-1 and C-3 of (1,2-bis-
(diphenylphosphino)ethane)(η3-1,3-diarylallyl)palladium tetrafluoroborates correlate with σ
Hammett substituent constants. For each complex the chemical shift at lower field indicates
the site of preferred attack by soft nucleophiles in the Tsuji-Trost reaction.
The palladium(0)-catalyzed allylation of nucleophiles
(the Tsuji-Trost reaction) is a synthetic method of high
acceptance due to its broad scope and easy experimental
procedure.1 The catalytic cycle (Figure 1) involves the
formation of the η3-allylpalladium complex, 1, as the key
intermediate which can be attacked by nucleophiles at
both termini of the allylic system. It is generally
accepted that nucleophiles attack preferentially at the
less hindered allylic terminus; thus product 2 is pre-
dominantly formed, mainly if R ) alkyl and aryl.
However, exceptions have been described and corre-
sponding explanations have been advanced. Thus, for
a given nucleophile regioselectivity depends on the
electronic nature of the stabilizing ligand, acceptor
ligands favoring attack at the more substituted termi-
nus.2 Also, for a given allylpalladium system regiose-
F igu r e 1.
lectivity can depend on the nucleophile, nonstabilized
these cases both electronic and steric effects are impor-
tant. Thus, strong electron-withdrawing groups, as
defined by positive σp values, direct the attack on
complexes 1 at the more remote side (γ attack: R′CO-
and R′OCO-,4 NC-,4d,e,5 PhSO2-,6 (R′O)2P(O)-,7 PhS-
8), whereas electron-donating groups placed on one
allylic terminal carbon atom favor the attack at the
same position (R attack: R′O-,9 anomeric oxygen atom
nucleophiles presenting some propensity to attack at the
more substituted terminus.3 Important electronic ef-
fects are evident when R in Figure 1 is a polar group
attached directly to the allylic framework, although in
X Abstract published in Advance ACS Abstracts, December 1, 1996.
(1) For reviews see: (a) Trost, B. M.; Verhoeven, T. R. Organopal-
ladium Compounds in Organic Synthesis and in Catalysis. In Com-
prehensive Organometallic Chemistry; Wilkinson, G., Stone, F. G. A.,
Abel, E. W., Eds.; Pergamon Press: New York, 1982; Vol. 8, Chapter
57. (b) Trost, B. M. Acc. Chem. Res. 1980, 13, 385. (c) Trost, B. M.
Chemtracts-Org. Chem. 1988, 1, 415. (d) Trost, B. M. Angew. Chem.,
Int. Ed. Engl. 1989, 28, 1173. (e) Godleski, S. A. Nucleophiles with
Allyl-Metal Complexes. In Comprehensive Organic Synthesis; Trost,
B. M., Fleming, I., Eds.; Pergamon Press: New York, 1991; Vol. 4,
Chapter 3.3. (f) Tsuji, J . Organic Synthesis with Palladium Com-
pounds; Springer-Verlag: Berlin, 1980. (g) Tsuji, J .; Minami, I. Acc.
Chem. Res. 1987, 20, 140. (h) Tsuji, J . Tetrahedron 1986, 42, 4361. (i)
Heck, R. F. Palladium Reagents in Organic Synthesis; Academic
Press: London, 1985. (j) Consiglio, G.; Waymouth, R. M. Chem. Rev.
1989, 89, 257. (k) Frost, C. G.; Howarth, J .; Williams, J . M. J .
Tetrahedron: Asymmetry 1992, 3, 1089. (l) Tsuji, J . Palladium
Reagents and Catalysis; J ohn Wiley & Sons: Chichester, U.K., 1995.
(m) Harrington, P. J . Transition Metal Allyl Complexes: Pd, W, Mo-
assisted Nucleophilic Attack. In Comprehensive Organometallic Chem-
istry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon
Press: New York, 1995; Vol. 12, Chapter 8.2.
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1981, 22, 2573. (e) Ognyanov, V. I.; Hesse, M. Synthesis 1985, 645. (f)
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1 1990, 1185.
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E.; Kanzler, S. Synthesis 1995, 539. (c) Principato, B.; Maffei, M.; Siv,
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Commun. 1996, 831.
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Synlett 1995, 969.
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1890. (b) Moineau, C.; Bolitt, V.; Sinou, D. J . Chem. Soc., Chem.
Commun. 1995, 1103.
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S0276-7333(96)00559-6 CCC: $14.00 © 1997 American Chemical Society

206 Organometallics, Vol. 16, No. 2, 1997
Moreno-Man˜as et al.
Sch em e 1a
a
Key: (a) Pd2(dba)3‚HCCl3, PhH (for 7a -d ,f); (b) Pd(dba)n or Pd2(dba)3‚HCCl3, LiCl, aq HCl, THF, EtOH (for 7e); (c) AgF4B,
acetone and then dppe, acetone.
Ta ble 1. 13C NMR Ch em ica l Sh ifts in δ Un its
in unsaturated carbohydrates10). The influence of other
(CDCl3) of Allyl Ca r bon Atom s in Com p ou n d s 8a -f
groups has been also described: In general acetoxy
8
X
Y
δ(C-1)
δ(C-2)
δ(C-3)
(MeCOO-) induces R attack11 although steric effects can
reverse this propensity.11a,b,d,12 The regioselectivity
when R ) fluorine depends on the nature of the
nucleophile.13 The trimethylsilyl group induces clearly
γ attack,14,15 although it is considered to be neither
electron-withdrawing nor electron-donating (σp in the
range 0.00 to -0.07), and the same applies to the
tributyltin group.15
8a
8b
8c
8d
8e
8f
NO2
Cl
H
Me
MeO
Cl
H
H
H
H
H
NO2
84.70
88.17
90.10
90.72
91.45
91.84
113.11
111.78
111.60
111.04
110.32
113.75
93.95
91.14
90.10
89.54
88.90
85.41
and the results indicated that the nucleophilic attacks
occur preferentially at the terminus remote from the
most electron-withdrawing group.17 Previous work on
systems involving cations of type 4 was not conclusive18
with regard to the regioselectivity problem as discussed
in our previous paper.17 We now have prepared (1,2-
bis(diphenylphosphino)ethane)(η3-1,3-diarylallyl)palla-
dium tetrafluoroborates, 8 (Scheme 1), and fully as-
signed their 13C NMR spectra. We find that the 13C
NMR chemical shifts of C-1 and C-3 at the allylic moiety
and, indirectly, the σp Hammett constants of the sub-
stituents at the aryl rings are correct indicators to
anticipate the site of attack by soft nucleophiles.
Complexes 8 were prepared by standard methods as
indicated in Scheme 1. Allyl chlorides 5, prepared from
the corresponding alcohols, were transformed into the
bis(µ-chloro)bis(1,3-diaryl-η3-allyl)dipalladium 7a -d ,f
by treatment with Pd2(dba)3‚HCCl3 in benzene. Since
complex 7e could not be prepared by this method, we
adopted and adapted a different procedure described by
Bosnich and co-workers.19 Thus, 7e was prepared by
reaction of alcohol 6 with Pd(0) species, aqueous HCl
and LiCl as indicated in Scheme 1. Treatment of
compounds 7 with silver tetrafluoroborate and then with
1,2-bis(diphenylphosphino)ethane in acetone afforded
cationic complexes 8a -f.
In summary, apart from steric effects, the regioselec-
tivity depends on the relative charge at both termini of
the allylic framework, and this can be modulated by the
substituents at the carbon skeleton and by the ligands
at palladium. On the other hand, it is well-known that
13C NMR chemical shifts are an indication of the relative
positive charge distribution2f,16 at the allylic termini.
In order to clarify the role of the isolated electronic
effects on the regioselectivity we studied some years ago
the palladium(0)-catalyzed allylations of soft nucleo-
philes with 1,3-diarylallyl acetates.17 These reactions
involved (η3-allyl)palladium complexes 4 (L ) PPh3)
featuring aryl rings differently substituted at para
positions (Figure 1). These aryl rings confer equal steric
requirements but different electronic requirements at
both ends of the allylic system. Complexes 4, with Ar1
) 4-ClPh or 4-MeOPh and Ar2 ) 4-NO2Ph, were studied,
(11) (a) Lu, X.; Huang, Y. J . Organomet. Chem. 1984, 268, 185. (b)
Trost, B. M.; Vercauteren, J . Tetrahedron Lett. 1985, 26, 131. (c) Geneˆt,
J .-P.; Uziel, J .; J uge, S. Tetrahedron Lett. 1988, 29, 4559. (d) Trost, B.
M.; Lee, C. B.; Weiss, J . M. J . Am. Chem. Soc. 1995, 117, 7247.
(12) Sjo¨gren, M. P. T.; Hansson, S.; A° kermark, B.; Vitagliano, A.
Organometallics 1994, 13, 1963.
(13) Shi, G.; Huang, X.; Zhang, F.-J . Tetrahedron Lett. 1995, 36,
6305.
(14) (a) Falck-Pedersen, M. L.; Benneche, T.; Undheim, K. Acta
Chem. Scand. 1989, 43, 251. (b) Urabe, H.; Inami, H.; Sato, F. J . Chem.
Soc., Chem. Commun. 1993, 1595. (c) Inami, H.; Ito, T.; Urabe, H.;
Sato, F. Tetrahedron Lett. 1993, 34, 5919. (d) Ollivier, J .; Salau¨n, J .
Synlett 1994, 949.
The 13C NMR data for the allylic part of the cationic
complexes 8 are given in Table 1. C-1 and C-3 have
different responses to the electronic character of the
group X. Thus, the chemical shift of C-1 is displaced
(15) Falck-Pedersen, M. L.; Benneche, T.; Undheim, K. Acta Chem.
Scand. 1992, 46, 1215.
(16) (a) A° kermark, B.; Krakenberger, B.; Hansson, S.; Vitagliano,
A. Organometallics 1987, 6, 620. (b) Yang, H.; Khan, M. A.; Nicholas,
K. M. Organometallics 1993, 12, 3485. (c) Malet, R.; Moreno-Man˜as,
M.; Parella, T.; Pleixats, R. Organometallics 1995, 14, 2463. (d) Malet,
R.; Moreno-Man˜as, M.; Parella, T.; Pleixats, R. J . Org. Chem. 1996,
61, 758.
(18) (a) Keinan, E.; Greenspoon, N. J . Org. Chem. 1983, 48, 3545.
(b) Keinan, E.; Peretz, M. J . Org. Chem. 1983, 48, 5302. (c) Keinan,
E.; Sahai, M.; Roth, Z.; Nudelman, A.; Herzig, J . J . Org. Chem. 1985,
50, 3558. (d) Hayashi, T.; Yamamoto, A.; Ito, Y. Chem. Lett. 1987, 177.
(19) Auburn, P. R.; Mackenzie, P. B.; Bosnich, B. J . Am. Chem. Soc.
1985, 107, 2033.
(17) Prat, M.; Ribas, J .; Moreno-Man˜as, M. Tetrahedron 1992, 48,
1695.

Allylpalladium Tetrafluoroborates
Organometallics, Vol. 16, No. 2, 1997 207
compounds 10a and 11a , arising from attack at C-1,
proximal to the phenyl ring substituted with the most
electron-donating methoxy group, are predominant to
an extent of 69% with respect to isomers 10b and 11b,
in agreement with our hypothesis. A blank experiment
in the absence of the catalytic system showed only
possible traces of reaction after a much extended re-
fluxing time (47 h).
Assignment of structures to isomers 10 was based on
the positive NOE between the olefinic proton
-CHCHdCH- and aromatic ortho protons of the phen-
yl ring (C6H5) observed in the major isomer, therefore
formulated 10a , and the positive NOE between the
olefinic proton -CHdCHCH- and aromatic protons
MeOCCHCH- observed in the minor isomer, therefore
formulated 10b. Similarly, for isomers 11 a positive
NOE was observed between the CH2 protons and the
aromatic ortho protons of the phenyl ring (C6H5) in the
major isomer formulated 11a and between the CH2
protons and the aromatic protons MeOCCHCH- for the
minor isomer 11b.
In summary, 13C NMR chemical shifts of the isolated
salts 8 give good support to understand the regioselec-
tivity of nucleophilic attacks of stabilized carbanions on
(η3-1,3-diarylallyl)palladium cations when steric effects
cancel out. The different response of chemical shifts for
C-1 and C-3 to the electronic character of the para
substituent is not intuitively clear, but it has prece-
dents.16c,d
F igu r e 2. Plot of 13C NMR chemical shifts of C-1 and C-3
vs σp for compounds 8a -e.
at higher field by electron-withdrawing substituents,
whereas the chemical shifts of C-2 and C-3 are displaced
at lower fields by the same substituents. Moreover, for
Y ) H (compounds 8a -e) ∆δ for C-1 and for C-3
correlate well with the σp substituent constants (∆δ(C-
1) ) - 0.28 - 6.32σp (r ) 0.998, sd ) 0.196) and ∆δ-
(C-3) ) 0.04 + 4.63σp (r ) 0.999, sd ) 0.088)). Similar
+
correlations with σp are much worse for these two
carbon atoms. Figure 2 represents plots of δ vs σp for
C-1 and C-3. On the contrary, ∆δ for C-2 correlates
+
+
much better with σp (∆δ(C-2) ) 0.04 + 1.78σp (r )
0.998, sd ) 0.072)). In spite of theoretical limitations
the correlation of differences in chemical shifts with
Hammett substituent constants has been proposed as
an experimental tool to determine the distribution of
the positive charge in (η3-allyl)palladium cations, good
correlations with σp+ rather than with σp at a given atom
being interpreted as an indication of the presence of a
substantial density of positive charge on it.16c,d The
correlation data, together with the much lower field
chemical shifts of the signals of the C-2 carbon atoms
(Table 1), point to a concentration of positive charge at
C-2. In fact palladium-catalyzed attacks at C-2 by hard
nucleophiles to afford cyclopropyl derivatives is well
precedented for substituted allyl systems in general20
and for the 1,3-diphenyl system in particular.20c,e How-
ever, soft nucleophiles attack at the terminal carbon
atoms of the allylic system when the palladium is
stabilized by phosphines.20e
It is reasonable to assume that both triphenylphos-
phine or 1,2-bis(diphenylphosphino)ethane should lead
to the same regioselection. However, since our previous
experiments were performed with triphenylphosphine
and with the nitro group as the common aryl substitu-
ent,17 we have now studied the reaction of the acetyl-
acetone conjugate base with a mixture of isomeric
acetates 9 in the presence of 1,2-bis(diphenylphosphino)-
ethane. This reaction is supposed to occur through the
cation of salt 8e. The results (Scheme 2) show that
Exp er im en ta l Section
NMR Exp er im en ts. The complete signal assignments for
products 8, 10, and 11 were made on a 400 MHz machine, by
concerted use of several gradient-enhanced experiments such
as 2D COSY,21 1H-13C 2D HMQC,22 and 1H-13C 2D HM-
BC.22,23 Required NOE data were extracted from phase-cycled
2D NOESY spectra24 or from gradient-enhanced 1D ROESY
(GROESY) experiments.25 Full technical details will be pub-
lished elsewhere. Proton and carbon chemical shifts are
referenced to the CDCl3 signals at 7.24 and 77.0 ppm,
respectively. Phosphorus chemical shifts are referenced to the
signal of phosphoric acid.
Su bstitu en t Con sta n ts. Substituent constant values for
correlations were taken from ref 26.
Bis(µ-ch lor o)bis(1-(4-n itr op h en yl)-3-p h en yl-η3-a llyl)d i-
p a lla d iu m , 7a . Gen er a l Meth od . A degassed solution of
3-chloro-3-phenyl-1-(4-nitrophenyl)-1-propene and its allylic
isomer, 5a (0.075 g, 0.28 mmol), in benzene (10 mL) was added
under inert atmosphere to a degassed suspension of Pd2(dba)3‚
HCCl3 (0.100 g, 0.10 mmol) in benzene (10 mL). The mixture
was magnetically stirred at room temperature for 52 h. The
formed solid was filtered out, washed throughly with benzene,
and dried to afford 7a (0.071 g, 97%): Mp 310 °C (d); IR (KBr)
1597, 1518, 1488, 1343, 690 cm-1; 1H NMR (250 MHz, C2D6SO)
δ 5.22 (d, J ) 11.0 Hz, 1H), 5.36 (d, J ) 12.1 Hz, 1H), 7.12 (t,
J ca. 12 Hz, 1H), 7.24-7.45 (m, 3H), 7.75 (d, J ) 7.7 Hz, 2H),
7.95 (d, J ) 8.6 Hz, 2H), 8.15 (d, J ) 8.6 Hz, 2H); 13C NMR
(62.9 MHz, C2D6SO) δ 79.50, 85.15, 108.80, 123.45, 128.08,
(21) Hurd, R. E. J . Magn. Reson. 1990, 87, 422.
(22) Hurd, R. E.; J ohn, B. K. J . Magn. Reson. 1991, 91, 648.
(23) Parella, T.; Sa´nchez-Ferrando, F.; Virgili, A. J . Magn. Reson.
1995, 112, 241.
(24) J eener, J .; Bachmann, P.; Ernst, R. R. J . Chem. Phys. 1979,
71, 4545.
(25) Adell, P.; Parella, T.; Sa´nchez-Ferrando, F.; Virgili, A. J . Magn.
Reson. B 1995, 108, 77.
(26) March, J . Advanced Organic Chemistry. Reactions, Mechanisms
and Structure, 4th ed.; J ohn Wiley and Sons: New York, 1992.
(20) (a) Carfagna, C.; Mariani, L.; Musco, A.; Sallese, G. J . Org.
Chem. 1991, 56, 3924. (b) Hoffmann, H. M. R.; Otte, A. R.; Wilde, A.
Angew. Chem., Int. Ed. Engl. 1992, 31, 234. (c) Otte, A. R.; Wilde, A.;
Hoffmann, H. M. R. Angew. Chem., Int. Ed. Engl. 1994, 33, 1280. (d)
Ohe, K.; Matsuda, H.; Morimoto, T.; Ogoshi, S.; Chatani, N.; Murai,
S. J . Am. Chem. Soc. 1994, 116, 4125. (e) Hoffmann, H. M. R.; Otte,
A. R.; Wilde, A.; Menzer, S.; Williams, D. J . Angew. Chem., Int. Ed.
Engl. 1995, 34, 100. (f) Castan˜o, A. M.; Aranyos, A.; Szabo´, K. J .;
Ba¨ckvall, J .-E. Angew. Chem., Int. Ed. Engl. 1995, 34, 2551.

208 Organometallics, Vol. 16, No. 2, 1997
Moreno-Man˜as et al.
Sch em e 2a
a
Key: (a) HNa, THF; (b) Pd(dba)n (n ) 1.5-2), 1,2-bis(diphenylphosphino)ethane; (c) 9, refluxing THF.
128.47, 128.74, 129.22, 136.56, 145.23, 146.06. Anal. Calcd
for C30H24Cl2N2O4Pd2: C, 47.41; H, 3.18; N, 3.69. Found: C,
47.10; H, 3.14; N, 3.39.
Bis(µ-ch lor o)bis(1-(4-m eth oxyp h en yl-3-p h en yl-η3-a llyl-
)d ip a lla d iu m , 7e. A degassed solution of 3-(4-methoxyphen-
yl)-1-phenyl-2-propen-1-ol, 6 (0.600 g, 2.52 mmol), in THF (3.5
mL) was added to a degassed mixture of Pd(dba)n (1.5 < n <
2) (0.483 g, 0.84-1.05 mmol), lithium chloride (0.183 g, 4.32
mmol), water (1 mL), THF (1.6 mL), and ethanol (2 mL). Then
12 N HCl (0.357 mL) was added to the dark suspension so
formed. The color immediately changed to greenish. The
mixture was magnetically stirred at room temperature for 3.5
h. The precipitate (0.314 g) was filtered out, washed with
benzene, and dried under phosphorus pentoxide: Mp 211-
214 °C; IR (KBr) 1606, 1510, 1491, 1253, 1174 cm-1; 1H NMR
(250 MHz, C2D6SO) δ 3.77 (s, 3H), 5.13 (d, J ) 11.7 Hz, 1H),
5.30 (d, J ) 12.1, 1H), 6.85 (t, J ca 12 Hz, 1H), 6.92 (m, 2H),
7.35 (m, 3H), 7.70 (d, J ) 8.7 Hz, 2H), 7.73 (d, J ) 7.3 Hz,
2H); 13C NMR (62.9 MHz, C2D6SO) δ 55.37, 82.34, 86.02,
106.06, 114.50, 128.20, 128.62, 128.88, 129.37, 130.22, 137.72,
159.67. No satisfactory elemental analysis could be obtained.
(1,2-Bis(d ip h e n ylp h osp h in o)e t h a n e )(η3-1-(4-n it r o-
p h en yl)-3-p h en yla llyl)p a lla d iu m Tetr a flu or obor a te, 8a .
Gen er a l Meth od . A degassed solution of 7a (0.111 g, 0.15
mmol) in acetone (6 mL) was added under inert atmosphere
to a magnetically stirred and degassed solution of silver
tetrafluoroborate (0.057 g, 0.29 mmol) in acetone (10 mL). The
mixture was magnetically stirred at room temperature for 1.75
h, and the formed precipitate was filtered off. To the yellow
transparent filtrate was added a solution of 1,2-bis(diphen-
ylphosphino)ethane (0.116 g, 0.29 mmol) in degassed acetone
(6 mL). The mixture turned brown, and it was magnetically
stirred for 24 h. The solvent was evaporated, and the residue
was treated with diethyl ether to afford an insoluble crop of
8a (0.188 g, 78% yield) which was further purified by digesting
again in diethyl ether. Data for compound 8a : Mp 117-119
°C; IR (KBr) 1594, 1514, 1436, 1337, 1055, 691 cm-1; 1H NMR
(400 MHz, CDCl3) δ 2.05-2.70 (m, 4H), 5.53 (m, 1H), 5.64 (m,
1H), 6.70 (d, J ) 7.3 Hz, 2H), 6.77 (t, J ca. 12.7 Hz, 1H), 6.85
(dd, J ) 8.3 and 1.6 Hz, 2H), 6.90 (m, 2H), 6.98-7.05 (m, 3H),
7.08 (t, J ) 7.3 Hz, 2H), 7.13 (d, J ) 8.3 Hz, 2H), 7.23 (t, J )
7.3 Hz, 2H), 7.24 (m, 1H), 7.36-7.53 (m, 6H), 7.55-7.65 (m,
6H), 7.68 (dd, J ) 7.3 and 1.6 Hz, 1H); 13C NMR (62.9 MHz,
CDCl3) δ 27.80 (dd, J ) 31.4 and 14.8 Hz), 28.88 (dd, J ) 32.4
and 14.8 Hz), 84.70 (dd, J ) 25.9 and 6.5 Hz), 93.95 (dd, J )
24.1 and 6.5), 113.11 (t, J ) 7.4 Hz), 123.97, 125.50-134.50,
Bis(µ-ch lor o)bis(1-(4-ch lor op h en yl)-3-p h en yl-η3-a llyl)-
d ip a lla d iu m , 7b. This compound was obtained in 80%
yield: Mp 222-226 °C; IR (KBr) 1596, 1488, 822, 753, 689
cm-1 1H NMR (250 MHz, C2D6SO) δ 5.22 (d, J ) 11.3 Hz,
;
2H), 6.97 (t, J ca 11 Hz, 1H), 7.38 (s, 5H), 7.74 (s, 4H); 13C
NMR (62.9 MHz, C2D6SO) δ 82.30, 83.72, 107.77, 128.57,
128.75, 128.87, 129.03, 130.41, 132.70, 136.63, 137.36. Anal.
Calcd for C30H24Cl4Pd2: C, 48.75; H, 3.27. Found: C, 48.65;
H, 3.29.
Bis(µ-ch lor o)bis(1,3-d ip h en yl-η3-a llyl)d ip a lla d iu m , 7c.
It was obtained in 87% yield: Mp 208-210 °C (lit.27 mp 230-
1
235 °C); IR (KBr) 1521, 1488, 1459, 754, 693 cm-1; H NMR
(250 MHz, C2D6SO) δ 5.25 (d, J ) 11.6 Hz, 2H), 6.98 (t, J )
11.6 Hz, 1H), 7.32-7.48 (m, 6H), 7.74 (dd, J ) 6.2 and 2.1,
4H) (this spectrum is coincident with that described in the
literature);28 13C NMR (62.9 MHz, C2D6SO) δ 83.60, 107.50,
128.40, 128.69, 128.92, 137.42.
Bis(µ-ch lor o)bis(1-(4-m eth ylp h en yl)-3-p h en yl-η3-a llyl)-
d ip a lla d iu m , 7d . This compound was obtained in ca. 100%
yield: mp 224 °C; IR (KBr) 1511, 1492, 811, 755, 689 cm-1
;
1H NMR (250 MHz, C2D6SO) δ 3.32 (s, 3H), 5.20 (d, J ) 12.2
Hz, 1H), 5.25 (d, J ) 12.2 Hz, 1H), 6.91 (t, J ca 12.2 Hz, 1H),
7.17 (d, J ) 8.0 Hz, 2H), 7.28-7.45 (m, 3H), 7.65 (d, J ) 8.0
Hz, 2H), 7.74 (d, J ) 8.1 Hz, 2H); 13C NMR (62.9 MHz, C2D6-
SO) δ 21.26, 83.17, 84.34, 107.02, 128.34, 128.69, 128.93,
129.64, 134.43, 137.58, 138.11. Anal. Calcd for C32H30Cl2-
Pd2: C, 55.04; H, 4.33. Found: C, 54.96; H, 4.33.
Bis(µ-ch lor o)bis(1-(4-ch lor op h en yl)-3-(4-n itr op h en yl)-
η3-a llyl)d ip a lla d iu m , 7f. This compound was obtained in
60% yield: mp 295-297 °C (lit.17 mp 298-300 °C); IR (KBr)
1595, 1511, 1342 cm-1 1H NMR (250 MHz, C2D6SO) δ 5.22
;
(d, J ) 12.1 Hz, 1H), 5.36 (d, J ) 12.1 Hz, 1H), 7.13 (t, J )
12.1 Hz, 1H), 7.45 (d, J ) 8.0 Hz, 2H), 7.79 (d, J ) 8.0 Hz,
2H), 8.00 (d, J ) 8.0 Hz, 2H), 8.19 (d, J ) 8.0 Hz, 2H); 13C
NMR (62.9 MHz, C2D6SO) δ 79.97, 83.96, 109.35, 123.91,
129.03, 129.64, 130.56, 133.14, 136.16, 145.54, 146.50.
(27) Hu¨ttel, R.; Kratzer, J .; Bechter, M. Chem. Ber. 1961, 94, 766.
(28) Hayashi, T.; Yamamoto, A.; Ito, Y.; Nishioka, E.; Miura, H.;
Yanagi, K. J . Am. Chem. Soc. 1989, 111, 6301.

Allylpalladium Tetrafluoroborates
Organometallics, Vol. 16, No. 2, 1997 209
135.46 (dd, J ) 25.7 and 11.0 Hz), 144.26 (dd, J ) 25.7 and
11.0 Hz), 145.61 (t, J ) 11.0 Hz); 31P NMR (162.0 MHz, CDCl3)
δ 47.74 (d, J PP ) 50.4 Hz), 50.26 (d, J PP ) 50.4 Hz). Anal.
Calcd for C41H36BF4NO2P2Pd: C, 59.34; H, 4.37; N, 1.69.
Found: C, 59.98; H, 4.67; N, 2.02.
28.90 (dd, J ) 31.4 and 14.8 Hz), 85.41 (dd, J ) 25.0 and 7.4
Hz), 91.84 (dd, J ) 23.1 and 7.4), 113.75 (t, J ) 6.5 Hz),
124.06-134.45, 144.23 (dd, J ) 5.6 and 2.8 Hz), 145.77 (t, J
) 3.0 Hz); 31P NMR (162.0 MHz, CDCl3) δ 47.62 (d, J ) 50.6
Hz), 48.82 (d, J ) 50.6 Hz).
(1,2-Bis(d ip h en ylp h osp h in o)et h a n e)(η3-1-(4-ch lor o-
p h en yl)-3-p h en yla llyl)p a lla d iu m Tetr a flu or obor a te, 8b.
This compound was obtained in 95% yield: mp 212 °C (d); IR
P d -Ca ta lyzed Rea ction of P en ta n e-2,4-d ion e w ith Ac-
eta tes 9. Pentane-2,4-dione (0.354 g, 3.54 mmol) and sodium
hydride (0.259 g of 40% suspension, 4.25 mmol), washed with
anhydrous THF, were mixed in anhydrous THF (25 mL) under
inert atmosphere. To the above mixture were sequentially
added a solution of Pd(dba)n (n ) 1.5-2.0) (0.102 g, 0.177-
0.223 mmol) and 1,2-bis(diphenylphosphino)ethane (0.141 g,
0.354 mmol) in THF (15 mL) and then a solution of a mixture
of 3-(4-methoxyphenyl)-1-phenyl-2-propen-1-ol acetate and
1-(4-methoxyphenyl)-3-phenyl-2-propen-1-ol acetate, 9 (1.00 g,
3.54 mmol), in THF (15 mL). The mixture was refluxed for
10 h and evaporated to dryness. The residue was taken in
diethyl ether and the ethereal solution was washed with
aqueous ammonium chloride and with aqueous sodium chlo-
ride, dried, and evaporated. The residue was chromato-
graphed through a silica gel column with hexanes-ethyl
acetate (9:1) as eluent to afford first 0.172 g (15.1%) of a
mixture of 3-(1-(4-methoxyphenyl)-3-phenyl-1-propenyl)-4-hy-
droxy-3-penten-2-one, 11a , and 3-(3-(4-methoxyphenyl)-1-
phenyl-1-propenyl)-4-hydroxy-3-penten-2-one, 11b, in a ratio
71:29: Bp 250 °C/0.5 mmHg; IR (film) 1605, 1510, 1259, 1178,
(KBr) 1436, 1055, 691 cm-1 1H NMR (400 MHz, CDCl3) δ
;
2.05-2.62 (m, 4H), 5.50 (t, J ca. 12.1 Hz, 2H), 6.58 (t, J ca.
12.6, 1H), 6.73 (dd, J ) 8.1 and 1.0 Hz, 2H), 6.79 (d, J ) 7.2
Hz, 2H), 6.83 (d, J ) 8.1 Hz, 2H), 6.92-6.98 (m, 4H), 7.02-
7.07 (m, 3H), 7.15-7.22 (m, 4H), 7.36-7.41 (m, 4H), 7.50-
7.60 (m, 7H), 7.60 (m, 2H); 13C NMR (62.9 MHz, CDCl3) δ
27.96-28.72 (m, 2C), 88.17 (dd, J ) 26.8 and 6.5 Hz), 91.14
(dd, J ) 24.1 and 6.5 Hz), 111.78 (t, J ) 7.4 Hz), 126.60-
133.84; 31P NMR (162.0 MHz, CDCl3) δ 46.17 (d, J PP ) 48.6
Hz), 47.70 (dd, J PP ) 48.6 Hz). Anal. Calcd for C41H36BClF4P2-
Pd: C, 60.10; H, 4.43. Found: C, 59.88; H, 4.46.
(1,2-Bis(d ip h en ylp h osp h in o)et h a n e)(η3-1,3-d ip h en yl-
a llyl)p a lla d iu m Tetr a flu or obor a te, 8c. This compound
was obtained in 71% yield: Mp 203-205 °C; IR (KBr) 1489,
1
1052, 690 cm-1; H NMR (250 MHz, CDCl3) δ 2.43 (m, 4H),
5.49 (dt, J ca. 13.5 and 6.6 Hz, 2H), 6.63 (t, J ca. 12.8 Hz, 1H),
6.70-7.60 (m, 30H); 13C NMR (62.9 MHz, CDCl3) δ 27.96 (t, J
) 23.1 Hz, 2C), 90.10 (t, J ) 15.7 Hz, 2C), 111.60 (t, J ) 7.40
Hz, 1C), 126.33, 126.67-126.85, 126.99, 127.36 (t, J ) 2.8 Hz),
127.64, 127.96, 128.30, 128.69 (t, J ) 1.9 Hz), 129.24 (t, J )
4.6 Hz), 129.76 (t, J ) 5.6 Hz), 131.08, 131.61, 133.30, (t, J )
6.5 Hz), 136.32 (t, J ) 4.6 Hz); 31P NMR (162.0 MHz, CDCl3)
δ 47.09 (s, 2P). Anal. Calcd for C41H37BF4P2Pd: C, 62.74; H,
4.75. Found: C, 62.44; H, 4.84.
1092, 1080, 1033, 827, 800, 699 cm-1
;
1H NMR (400 MHz,
CDCl3) for 11a δ 1.92 (s, 6H), 3.43 (d, J ) 7.3 Hz, 2H), 3.79 (s,
3H), 6.37 (t, J ) 7.3 Hz, 1H), 6.84 (dd, J ) 8.8 and 1.9 Hz,
2H), 7.1-7.4 (m, 7H), 16.65 (s, 1H), for 11b δ 1.93 (s, 6H),
3.39 (d, J ) 7.3 Hz, 2H), 3.78 (s, 3H), 6.45 (t, J ) 7.3 Hz, 1H),
6.84 (dd, J ) 8.8 and 1.9 Hz, 2H), 7.1-7.4 (m, 7H), 16.70 (s,
1H); 13C NMR (100 MHz, CDCl3) for 11a and 11b δ 23.4 and
23.4 (CCH3), 36.0 and 35.2 (CH2), 55.29 (for both, OCH3), 110.5
and 110.3 (C-3), 114.0 and 114.1 (CH3OCCH), 125.8, 126.2,
127.0, 127.5, 128.0, 128.3 (CH2CCH for 11a ), 128.6, 129.2 (CH3-
OCCHCH for 11b), 129.4 and 131.8 (olefinic CCH), 132.9 (CH3-
OCCHCHC for 11a ), 135.5 and 135.7 (CH2C aromatic), 140.1
and 140.4 (olefinic CCH), 159.2 (CH3OC for 11a ), 191.5 (for
both, C-2). Anal. Calcd for C21H22O3: C, 78.23; H, 6.88.
Found (for the mixture): C, 78.31; H, 6.98. On further elution
a mixture (0.690 g, 60.4%) of 3-(1-(4-methoxyphenyl)-3-phenyl-
2-propenyl)pentane-2,4-dione, 10a , and 3-(3-(4-methoxyphen-
yl)-1-phenyl-2-propenyl)pentane-2,4-dione, 10b, in a ratio 69:
31, was obtained: IR (film) 1718, 1694, 1610, 1513, 1497, 1358,
1251, 1178, 1153, 1031, 966, 830, 822, 742, 699, 693 cm-1; 1H
NMR (400 MHz, CDCl3) for 10a δ 1.95 (s, 3H), 2.25 (s, 3H),
3.75 (s, 3H), 4.22-4.30 (m, 2H), 6.17 (dd, J ) 15.7 and 4.8,
1H), 6.39 (d, J ) 15.7 Hz, 1H), 6.85 (d, J ) 8.4 Hz, 2H), 7.16
(d, J ) 8.4 Hz, 2H), 7.30-7.45 (m, 5H), for 10b δ 1.93 (s, 3H),
2.25 (s, 3H), 3.80 (s, 3H), 4.22-4.30 (m, 2H), 6.04 (ddd, J )
15.7, 6.2, and 1.5, 1H), 6.36 (d, J ) 15.7 Hz, 1H), 6.80 (d, J )
8.4 Hz, 2H), 7.22 (d, J ) 8.4 Hz, 2H), 7.24 (d, J ) 8.4 Hz, 2H),
7.30-7.45 (m, 3H); 13C NMR (62.9 MHz, CDCl3) for the
mixture δ 29.6 and 29.8, 48.2 and 49.1, 55.0 and 55.1, 74.4
and 74.5, 113.8 and 114.2, 126.1, 126.9, 127.0, 127.5, 127.7,
128.3, 128.8, 129.4, 130.9, 131.2, 131.9, 136.5, 140.2, 158.5 and
159.1, 202.7 and 202.8. Anal. Calcd for C21H22O3: C, 78.23;
H, 6.88. Found (for the mixture): C, 78.24; H, 6.94.
(1,2-Bis(d ip h en ylp h osp h in o)et h a n e)(η3-1-(4-m et h yl-
p h en yl)-3-p h en yla llyl)p a lla d iu m Tetr a flu or obor a te, 8d .
This compound was obtained in 92% yield: mp 213-215 °C;
1
IR (KBr) 1559, 1053, 691 cm-1; H NMR (400 MHz, CDCl3) δ
2.17 (s, 3H), 2.21-2.84 (m, 4H), 5.40 (m, 1H), 5.49 (m, 1H),
6.53 (t, J ) 12.8 Hz, 1H), 6.69-6.78 (m, 6H), 6.90 (d, J ) 7.9
Hz, 2H), 6.92 (d, J ) 7.9 Hz, 2H), 6.77-7.05 (m, 3H), 7.11 (t,
J ) 7.9 Hz, 2H), 7.15 (t, J ) 7.9 Hz, 2H), 7.29-7.40 (m, 4H),
7.42-7.56 (m, 8H); 13C NMR (62.9 MHz, CDCl3) δ 21.20, 27.89
(dt, J ) 23.1 and 2.8 Hz, 2C), 89.54 (t, J ) 15.7 Hz), 90.72 (t,
J ) 15.7 Hz), 111.04 (t, J ) 7.4 Hz), 126.55-126.87, 127.33,
128.69, 129.00-129.45, 129.66 (q, J ) 5.6 Hz), 132.02 (d, J )
12.0 Hz), 131.45-131.80, 131.94, (d, J ) 10.2 Hz), 133.08-
133.52, 136.45 (t, J ) 4.0 Hz), 137.58 (t, J ) 2.8 Hz); 31P NMR
(162.0 MHz, CDCl3) δ 46.21 (s, 2P). Anal. Calcd for
C
42H39BF4P2Pd: C, 63.14; H, 4.92. Found: C, 63.06; H, 4.92.
(1,2-Bis(d ip h e n ylp h osp h in o)e t h a n e )(η3-1-(4-m e t h -
oxyp h en yl)-3-p h en yla llyl)p a lla d iu m Tetr a flu or obor a te,
8e. It was obtained in 85% yield: Mp 192 °C (d); IR (KBr)
1513, 1436, 1055, 691 cm-1 1H NMR (400 MHz, CDCl3) δ
;
2.12-2.53 (m, 4H), 3.66 (s, 3H), 5.32 (m, 1H), 5.51 (m, 1H),
6.44 (d, J ) 8.1 Hz, 2H), 6.50 (t, J ) 12.8 Hz, 1H), 6.76 (m,
4H), 6.86-7.05 (m, 7H), 7.14 (m, 4H), 7.26-7.40 (m, 4H), 7.45-
7.60 (m, 8H); 13C NMR (62.9 MHz, CDCl3) δ 27.90 (dd, J )
26.8 and 16.7 Hz, 2C), 55.22, 88.90 (dd, J ) 23.1 and 9.2 Hz),
91.45 (dd, J ) 22.2 and 8.3), 110.32 (t, J ) 7.4 Hz), 114.07,
126.76 (t, J ) 3.7 Hz), 127.24, 128.10 (t, J ) 3.7 Hz), 128.68,
129.13-129.77, 131.02 (dd, J ) 7.4 and 1.9 Hz), 131.50-
132.40, 133.31 (dd, J ) 16.7 and 13.0), 136.46-136.61; 31P
NMR (162.0 MHz, CDCl3) δ 45.49 (d, J PP ) 48.3 Hz), 46.08 (d,
J PP ) 48.3 Hz). Anal. Calcd for C42H39BF4OP2Pd: C, 61.90;
H, 4.82. Found: C, 61.69; H, 4.93.
Ack n ow led gm en t. Financial support from the DGI-
CYT (Ministry of Education and Science of Spain),
through project PB93-0896, and from CIRIT (Generali-
tat de Catalunya), through project GRQ 93-2011, and a
predoctoral scholarship (to F.P.) are gratefully acknowl-
edged.
(1,2-Bis(d ip h en ylp h osp h in o)et h a n e)(η3-1-(4-ch lor o-
p h en yl)-3-(4-n itr op h en yl)a llyl)p a lla d iu m Tetr a flu or obo-
r a te, 8f. This compound was obtained in 56% yield: mp 134-
135 °C (lit.17 mp 140 °C); IR (KBr) 1594, 1514, 1436, 1340,
Su p p or t in g In for m a t ion Ava ila b le: IR, 1H NMR, 13C
NMR, and 31P NMR spectra of compounds 8 (20 pages).
Ordering information is given on any current masthead page.
1
1055, 691 cm-1; H NMR (250 MHz, CDCl3) δ 2.20-2.72 (m,
4H), 5.43 (ddd, J ) 12.8, 7.9 and 2.6 Hz, 1H), 5.55 (ddd. J )
12.8, 9.9 and 3.3 Hz, 1H), 6.82 (1H), 6.72-7.64 (m, 28H); 13C
NMR (62.9 MHz, CDCl3) δ 28.38 (dd, J ) 31.4 and 14.8 Hz),
OM9605591