New chiral cyclopalladated complexes based on the pinane and bornane imines

Article abstract of DOI:10.1007/s11172-013-0101-6

2α-Hydroxypinan-3-one imino derivatives react with lithium tetrachloropalladate to form palladacycles, while similar bornane derivative undergo cyclopalladation only when treated with palladium acetate.

Full text of DOI:10.1007/s11172-013-0101-6

Russian Chemical Bulletin, International Edition, Vol. 62, No. 3, pp. 745—750, March, 2013
745
New chiral cyclopalladated complexes based on the pinane and bornane imines*
A. V. Kuchin,a Ya. A. Gur´eva,a L. L. Frolova,a I. N. Alekseev,a and O. A. Zalevskayab
aInstitute of Chemistry, Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences,
48 ul. Pervomaiskaya, 167982 Syktyvkar, Russian Federation.
Fax: +7 (821) 221 8477. Eꢀmail: gurjevaꢀja@chemi.komisc.ru
bSyktyvkar State University,
55 Octyabr´skii prosp., 167001 Syktyvkar, Russian Federation.
Fax: +7 (821) 243 6820
2ꢀHydroxypinanꢀ3ꢀone imino derivatives react with lithium tetrachloropalladate to form
palladacycles, while similar bornane derivative undergo cyclopalladation only when treated
with palladium acetate.
Key words: palladium complexes, palladacycles, imines, bicyclic monoterpenoids.
Chiral palladacycles, possessing high thermal, oxidaꢀ
tion, and hydrolytic stability, are known1,2 to be successꢀ
fully used in asymmetric synthesis and catalysis. Earliꢀ
er,3,4 we have studied the cyclopalladation of 2ꢀhydrꢀ
oxypinanꢀ3ꢀone and camphor benzylimines and found that
the direction of cyclometallation depended on the strucꢀ
tural specificity of the ligand: camphor ꢀmethylbenzylꢀ
imine formed the orthoꢀpalladated complex 1, whereas in
the case of camphor benzylimine, the cyclometallation of
the bornane fragment for the first time was accomplished
at the methyl group at position 1 (complex 2).
converted to the corresponding ꢀhydroxy ketones in orꢀ
der to further develop the vicinal iminoꢀ and hydroxy
groups in them (Scheme 1). The oxidation of ꢀpinene 3
with potassium permanganate in aqueous acetone led5 to
2ꢀhydroxypinanꢀ3ꢀone (5) in 50% yield.
Camphorquinone 6 was obtained according to the deꢀ
scribed procedure6 by the oxidation of bromocamphor with
atmospheric oxygen in DMSO in 84% yield (see Scheme 1).
The ketalization of camphorquinone with ethylene glycol
took place only at one keto group, and the reduction of
the other group with sodium borohydride with subsequent
hydrolysis of the intermediate hydroxy ketal led to 2ꢀhydrꢀ
oxybornanꢀ3ꢀone (7) in 75% yield.7 The new ligands, viz.,
imines 8—11, were synthesized by the condensation of the
corresponding oxo derivatives with diphenylmethylamine,
benzylamine, and (S)ꢀꢀmethylbenzylamine in 49—56%
yields (see Scheme 1). The data on the studies of imines
12—16 as the ligands for the preparation of chiral palladiꢀ
um complexes were reported earlier.3,4,8,9
The formation of the imines proceeded stereoselecꢀ
tively: their NMR spectra exhibited one set of signals, that
indicated the formation of one geometrical isomer. The
studies of the NOE interactions showed that imines 8 and
9 have Eꢀconfiguration, whereas imines 10 and 11 have
Zꢀconfiguration. Thus, the NOESY spectra of imines 8
and 9 demonstrated the interaction of the benzyl protons
with the protons of the terpene fragment at positions 4
and 3, respectively, that confirmed the Eꢀconfiguration of
the imines obtained. The Zꢀconfiguration of imines 10
and 11 was confirmed by the NOE interaction of their
protons at position 11 with the proton of the terpene fragꢀ
ment at position 2 and the proton of the hydroxy group.
The synthesized imines 8—11 and 16 were studied in
the cyclopalladation reaction. Benzylamine derivatives are
known to readily undergo the palladation at the aromatic
In the present work, we report the synthesis of new
cyclopalladated complexes based on the enantiomerically
pure pinane and bornane derivatives containing vicinal
iminoꢀ and hydroxy groups and some other types of funcꢀ
tionalization.
Results and Discussion
Enantiopure natural bicyclic monoterpenoids (–)ꢀꢀ
pinene (3) and (–)ꢀcamphor (4) were used as the starting
chiral compounds for the synthesis of imines. They were
* Dedicated to Academician of the Russian Academy of Sciences
I. P. Beletskaya on the occasion of her anniversary.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 0745—0749, March, 2013.
1066ꢀ5285/13/6203ꢀ745 © 2013 Springer Science+Business Media, Inc.

746
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 3, March, 2013
Kuchin et al.
Scheme 1
R = Ph (8, 9), H (10, 12, 14), Me (11, 13, 15)
Scheme 2
ring. We found that imine 8 under the Cope reaction conꢀ
ditions, which suggested that the ligand reacted with lithꢀ
ium tetrachloropalladate (Li2PdCl4) in the presence of
sodium acetate as a base (see the data in Ref. 3), formed
orthoꢀpalladated dimer 17 in 58% yield (Scheme 2).
The formation of the orthoꢀpalladated complex 17 was
unambiguously confirmed by the 1H and 13C NMR specꢀ
tra, in which only one set of signals was observed, that
indicated the formation of one individual isomer. The
orthoꢀdisubstituted aromatic ring was identified by the sigꢀ
nals in the region of aromatic protons, which contained
the signals for four nonequivalent protons with the indicaꢀ
R = Ph (8, 17), H (12, 18), Me (13, 19)
1
tive splitting. The H NMR spectrum still retained the
took place under the Cope reaction conditions. When lithꢀ
ium tetrachloropalladate was replaced with stronger elecꢀ
trophile palladium acetate, the reaction gave cyclometalꢀ
lated complexes 1 and 2. Therefore, we used similar conꢀ
ditions for the studies of the ligand properties of camphor
diphenylmethylimine 9. The results were not unexpected:
the reaction of imine 9 with lithium tetrachloropalladate
gave the coordination palladium compound 20, whereas
treatment with palladium acetate led to the orthoꢀpalladaꢀ
tion of the aromatic ring (Scheme 3).
splitting and the integral intensity of the signals for the
protons of the second monosubstituted benzene ring.
Comparing the reactivity of imines 8, 12, and 13, one
can note that the presence of a substituent at ꢀposition of
the benzyl fragment facilitates the orthoꢀpalladation: the
phenylꢀ and methylꢀsubstituted benzylimines 8 and 13
form the binuclear cyclopalladated complexes 17 and 19
(see Ref. 3) in close yields (58 and 53%, respectively) even
in the absence of AcONa as a base.
Earlier,4 we have studied the cyclometallation of camꢀ
phor benzylꢀ and ꢀmethylbenzylimines 14 and 15 and
have shown that no cyclopalladation of these compound
The formation of orthoꢀdisubstituted aromatic ring in
complex 21 was confirmed by the NMR spectra. Thus,
the 1H NMR spectra exhibit the signals for the four nonꢀ

New cyclopalladated complexes
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 3, March, 2013
747
Scheme 3
Scheme 4
Scheme 5
equivalent aromatic protons as separate multiplets, whereꢀ
as the 13C NMR spectra have of the signals the methine
aromatic groups.
It should be noted that an additional chiral center
emerges at position 11 upon the orthoꢀpalladation of
diphenylmethylimine derivatives 8 and 9. The presence of
only one set of signals in the NMR spectra of the correꢀ
sponding palladacycles 17 and 21 indicates that orthoꢀ
palladation is a diastereoselective process.
Unlike imines 9, 14, and 15 forming individual cycloꢀ
metallated complexes 21, 1, and 2, respectively, the orthoꢀ
palladation of camphorquinone ꢀmethylbenzylimine 16
leads to a mixture of geometrical isomers (Scheme 4). The
1H NMR spectrum of complex 22 exhibits two sets of
signals with the 5 : 1 ratio of intensities.
The studies of the reaction of 2ꢀhydroxybornanꢀ3ꢀ
one imines 10 and 11 with lithium tetrachloropalladate
and palladium acetate showed that no cyclopalladation of
these compounds occured: the complexes 23 and 24 were
formed instead in 58 and 64% yields, respectively (Scheme 5).
The NMR spectra of complexes 23 and 24 with the
monodentate coordinated ligands still have all the signals
corresponding to the starting imines with their slight lowꢀ
field shift for the nuclei arranged close to palladium. The
splitting and the integral intensity of the signals for the
protons of the benzene ring correspond to the monoꢀ
substitution. The absence of the double signals indicate
the formation of individual isomers.
R = H (10, 23), Me (11, 24)
In conclusion, we for the first time studied the cycloꢀ
palladation reaction of a number of imines of the pinane
and bornane structures and found that the 2ꢀhydroxyꢀ
pinanꢀ3ꢀone derivatives readily enough underwent cycloꢀ
palladation in the reaction with lithium tetrachloropalladꢀ
ate. Unlike the pinane structures, the bornane derivatives
underwent cyclometallation only when treated with pallaꢀ
dium acetate.
Experimental
IR spectra (neat or in KBr pellets) were recorded on a Shiꢀ
madzu IR Prestige 21 spectrometer. H and 13C NMR spectra
were recorded on a Bruker AVANCEꢀIIꢀ300 spectrometer (300
(1H) and 75 MHz (13C)) in CDCl3, using residual signals of
1

748
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 3, March, 2013
Kuchin et al.
chloroform ( 7.27,  77.00) and DMSO ( 2.50) as referꢀ
44.02 (C(4)), 47.15 (C(7)), 54.05 (C(1)), 68.25 (C(11)), 126.44
(C(15)), 126.46 (C(15´)), 127.50 (C(13)), 127.56 (C(13´)),
128.18 (C(14)), 128.25 (C(14´)), 145.00 (C(12)), 145.09 (C(12´)),
181.56 (C(2)).
H
C
H
ences. The signal were assigned using the 13C NMR spectra
recorded in the Jꢀmodulation mode and the 2D correlation specꢀ
1
1
tra H—1H (COSY, NOESY) and H—13C (HSQC, HMBC).
Optical rotation was measured on a Kruss P3002RS automatic
polarimeter (Germany). Elemental analysis was performed on
an EA 1110 elemental analyzer.
(1R,2S,4S)ꢀ3ꢀBenzyliminoꢀ1,7,7ꢀtrimethylbicyclo[2.2.1]ꢀ
21
heptanꢀ2ꢀol (10). The yield was 0.68 g (53%), []D +24.1
(c 0.5, CHCl3), bright yellow oil soluble in diethyl ether, chloroꢀ
The reaction progress was monitored by TLC on Sorbfil
plates, using the hexane—Et2O and the benzene—acetone solꢀ
vent systems as eluents. To visualize compounds, the plates were
treated with the iodine vapors. AlfaꢀAesar silica gel (70—230 )
was used for column chromatography. (S)ꢀꢀMethylbenzylamine
(ee 99.5%), (1S)ꢀꢀpinene (3) (Acros Organics), camphor 4 reꢀ
crystallized from ethanol ([]D –40.9 (c 1.0, CHCl3)), and palꢀ
ladium chloride and acetate were used without additional puriꢀ
fication.
form, acetone, benzene, and DMSO, Rf 0.5 (hexane—diethyl
1
ether, 3 : 1). IR, /cm–1: 3319 (OH), 1644 (C=N). H NMR
(CDCl3), : 0.90 (s, 3 H, C(9)H3); 0.96 (s, 3 H, C(10)H3); 1.04
(s, 3 H, C(8)H3); 1.38 (m, 1 H, H(6)); 1.66 (m, 1 H, H(5));
1.72 (m, 1 H, H(6)); 1.91 (br.s, 1 H, OH); 2.04 (m, 1 H, H(5));
2.16 (dd, 1 H, H(4), J = 4.1 Hz, J = 4.3 Hz); 3.37 (d, 1 H, H(2),
J = 4.5 Hz); 3.78 (d, 1 H, H(11), J = 15 Hz); 3.82 (d, 1 H,
H(11), J = 15 Hz); 7.25—7.37 (m, 5 H, H arom.). 13C NMR
(CDCl3), : 9.40 (C(10)), 18.83 (C(5)), 19.42 (C(8)), 19.73
(C(9)), 32.10 (C(6)), 44.17 (C(1)), 47.22 (C(4)), 52.78 (C(11)),
58.40 (C(7)), 64.68 (C(2)), 127.02 (C(15)), 128.18 (C(14)),
128.35 (C(13)), 140.01 (C(12)), 219.30 (C(3)).
(1R,2S,4S)ꢀ3ꢀ[(1S)ꢀꢀMethylbenzylimino]ꢀ1,7,7ꢀtrimethylꢀ
bicyclo[2.2.1]heptanꢀ2ꢀol (11). The yield was 83 mg (51%),
[]D21 –26.0 (c 0.5, CHCl3), bright yellow oil soluble in diethyl
ether, chloroform, acetone, benzene, and DMSO, Rf 0.6 (hexꢀ
ane—diethyl ether, 3 : 1). IR, /cm–1: 3175 (OH), 1686 (C=N).
1H NMR (CDCl3), : 0.80 (s, 3 H, C(9)H3); 0.90 (s, 3 H,
C(8)H3); 0.92 (s, 3 H, C(10)H3); 1.29 (m, 1 H, H(6)); 1.41 (d, 3 H,
C(12)H3, J = 6.5 Hz); 1.45 (m, 1 H, H(5)); 1.51 (m, 1 H,
H(4)); 1.62 (m, 1 H, H(6)); 1.89 (m, 1 H, H(5)); 1.90 (br.s,
OH); 3.30 (d, 1 H, H(2), J = 4.5 Hz); 3.93 (q, 1 H, H(11),
J = 6.5 Hz); 7.20—7.40 (m, 5 H, H arom.). 13C NMR (CDCl3),
: 9.43 (C(10)), 19.14 (C(5)), 19.20 (C(8)), 19.68 (C(9)), 24.36
(C(12)), 32.25 (C(6)), 43.89 (C(1)), 48.34 (C(4)), 58.34 (C(7)),
59.35 (C(11)), 65.64 (C(2)), 126.97 (C(16)), 127.04 (C(15)),
128.17 (C(14)), 145.78 (C(13)), 220.83 (C(3)).
20
(1R,2R,5R)ꢀ2ꢀHydroxypinanꢀ3ꢀone (5) ([]D +39 (c 0.9,
20
CHCl3), m.p. 39—40 C), (1R,4S)ꢀcamphorquinone (6) ([]D
–97.8 (c 1.5, toluene)), and (1R,2S,4S)ꢀ2ꢀhydroxybornanꢀ3ꢀone
(7) ([]D20 –132.7 (c 0.1, EtOH)) were synthesized according to
the known procedures.5—7
Preparation of imines (general procedure). The correspondꢀ
ing keto derivative (7 mmol) and primary amine (8 mmol) were
dissolved in anhydrous benzene (20 mL) or toluene (20 mL).
Then, boron trifluoride etherate (3 mmol) was added, and the
mixture was refluxed for 4—15 h. The reaction progress
was monitored by TLC (eluent a mixture of hexane—diethyl
ether, visualization by iodine). The compounds were isolated
by column chromatography on SiO2 (eluent a mixture of light
petroleum—diethyl ether). All the compounds were obtained
as oils.
(1R,2R,5R)ꢀ3ꢀDiphenylmethyliminoꢀ2,6,6ꢀtrimethylbicycloꢀ
21
[3.1.1]heptanꢀ2ꢀol (8). The yield was 0.9 g (49%), []D –32.2
(c 0.2, CHCl3), bright yellow oil soluble in diethyl ether, chloroꢀ
form, acetone, benzene, and DMSO, Rf 0.5 (hexane—diethyl
Synthesis of cyclopalladated complexes. A. A suspension of
palladium(II) chloride (0.2 mmol) and lithium chloride (0.5 mmol)
in methanol (5 mL) was boiled with a reflux condenser in a water
bath for 1 h. A dark red solution of lithium tetrachloropalladate
was poured to a solution of imine (0.2 mmol) and sodium acetate
(0.2 mmol) in methanol (5 mL), and the reaction mixture
was stirred at room temperature for 5—7 h. The solvent
was evaporated from the reaction mixture in vacuo, the residue
was dissolved in benzene and purified by chromatography
(SiO2, eluent a mixture of benzene—acetone). The oil left
after evaporation of the solvents was recrystallized from the sysꢀ
tem benzene—hexane to obtain the complex compound as
powders.
B. A suspension of imine (0.4 mmol) and palladium acetate
(0.4 mmol) in toluene (15 mL) was heated for 3—6 h at 60 C.
The solvent was evaporated from the reaction mixture in vacuo,
then a solution of lithium chloride (2 mmol) in methanol (5 mL)
was added to the residue. The reaction mixture was stirred for
3—5 h at room temperature. The solvent was evaporated from
the reaction mixture in vacuo, the residue was dissolved in benꢀ
zene and purified by chromatography (SiO2, eluent a mixture of
benzene—acetone). The oil left after evaporation of the solvents
was recrystallized from the system benzene—hexane to obtain
the complex compound as powders.
1
ether, 3 : 1). IR, /cm–1: 3435 (OH), 1647 (C=N). H NMR
(CDCl3), : 0.78 (s, 3 H, C(9)H3); 1.34 (s, 3 H, C(8)H3); 1.57
(d, 1 H, H(7), J = 10.6 Hz); 1.64 (s, 3 H, C(10)H3); 2.05 (m, 1 H,
H(5), J = 5.9 Hz); 2.15 (dd, 1 H, H(1), J = 5.9 Hz, J = 6.0 Hz);
2.36 (dddd, 1 H, H(7), J = 2.5 Hz, J = 5.9 Hz, J = 6.0 Hz,
J = 10.6 Hz); 2.58 (ddd, 1 H, H(4), J = 2.5 Hz, J = 5.8 Hz,
J = 18 Hz); 2.62 (s, 1 H, OH); 2.73 (dd, 1 H, H(4), J = 3.0 Hz,
J = 18 Hz); 5.73 (s, 1 H, H(11)); 7.22—7.46 (m, 10 H, H arom.).
13C NMR (CDCl3), : 22.88 (C(9)), 27.39 (C(8)), 28.14 (C(7)),
28.60 (C(10)), 33.68 (C(4)), 38.44 (C(5)), 38.49 (C(6)), 50.06
(C(1)), 66.60 (C(11)), 76.90 (C(2)), 126.77 (C(15)), 126.88
(C(15´)), 127.31 (C(13)), 127.50 (C(13´)), 128.43 (C(14)), 128.50
(C(14´)), 144.13 (C(12), C(12´)), 175.77 (C(3)).
(1S,4S)ꢀ2ꢀDiphenylmethyliminoꢀ1,7,7ꢀtrimethylbicyclo[2.2.1]ꢀ
23
heptane (9). The yield was 1.3 g (51%), []D +19.2 (c 0.3,
CHCl3), colorless oily liquid soluble in diethyl ether, chloroꢀ
form, acetone, benzene, and DMSO, Rf 0.6 (hexane—diethyl
ether, 3 : 1). IR, /cm–1: 1682 (C=N). 1H NMR (CDCl3),
: 0.70 (s, 3 H, C(9)H3); 0.97 (s, 3 H, C(8)H3); 1.14 (s, 3 H,
C(10)H3); 1.18 (m, 1 H, H(5), J = 10 Hz); 1.42 (m, 1 H, H(6),
J = 13 Hz); 1.72 (m, 1 H, H(6), J = 13 Hz); 1.85 (m, 1 H,
H(5), J = 10 Hz); 1.94 (dd, 1 H, H(4), J = 4.3 Hz, J = 4.7 Hz);
1.96 (d, 1 H, H(3), J = 17 Hz); 2.40 (ddd, 1 H, H(3), J = 4.0 Hz,
J = 7.5 Hz, J = 17 Hz); 5.51 (s, 1 H, H(11)); 7.19—7.48 (m, 10 H,
H arom.). 13C NMR (CDCl3), : 11.58 (C(10)), 19.08
(C(8)), 19.56 (C(9)), 27.49 (C(5)), 32.04 (C(6)), 35.94 (C(3)),
Diꢀꢀchlorobis{2ꢀ[((1R,2R,5R)ꢀ2ꢀhydroxyꢀ2,6,6ꢀtrimethylꢀ
bicyclo[3.1.1]heptꢀ3ꢀylideneamino)(phenyl)methyl]phenylꢀC,N}ꢀ
dipalladium(II) (17). The yield was 133 mg (58%), m.p. 159—160 C

New cyclopalladated complexes
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 3, March, 2013
749
20
(with decomp.), []D +115.4 (c 0.4, CHCl3), yellow powder
(benzene—acetone, 10 : 1). Found (%): C, 53.10; H, 5.72;
N, 3.16. C36H44Cl2N2O2Pd2. Calculated (%): C, 52.70; H, 5.37;
N, 3.41. IR, /cm–1: 1745 (C=O), 1651 (C=N). 1H NMR
(CDCl3), : 0.92 (s, 3 H, C(9)H3); 1.06 (s, 3 H, C(10)H3); 1.09
(s, 3 H, C(8)H3); 1.57 (m, 1 H, H(6)); 1.80 (d, 3 H, C(12)H3,
J = 6.4 Hz); 1.87 (m, 1 H, H(5)); 1.88 (m, 1 H, H(6)); 2.26
(m, 1 H, H(5)); 3.62 (d, 1 H, H(4), J = 4.1 Hz); 6.30 (q, 1 H, H(11),
J = 6.4 Hz); 6.84 (d, 1 H, H(18), J = 7.2 Hz); 6.92 (dd, 1 H,
H(16), J = 7.1 Hz, J = 7.7 Hz); 6.98 (dd, 1 H, H(17), J = 7.1 Hz,
J = 7.2 Hz); 7.15 (d, 1 H, H(15), J = 7.7 Hz). 13C NMR (CDCl3),
: 9.32 (C(10)), 17.72 (C(8)), 21.11 (C(9)), 24.87 (C(5)), 26.60
(C(12)), 30.27 (C(6)), 44.39 (C(7)), 57.71 (C(4)), 60.25 (C(1)),
72.16 (C(11)), 120.16 (C(18)), 125.24 (C(17)), 125.39 (C(16)),
132.99 (C(15)), 140.84 (C(13)), 152.55 (C(14)), 175.12 (C(3)),
201.51 (C(2)).
soluble in chloroform, acetone, benzene, and DMSO, Rf 0.4
(benzene—acetone, 10 : 1). Found (%): C, 57.80; H, 5.64;
N, 2.66. C46H52Cl2N2O2Pd2. Calculated (%): C, 58.20; H, 5.49;
N, 2.95. IR, /cm–1: 3204 (OH), 1632 (C=N). 1H NMR
(CDCl3), : 0.62 (s, 3 H, C(9)H3); 1.30 (s, 3 H, C(8)H3); 1.36
(d, 1 H, H(4), J = 20 Hz); 1.88 (m, 1 H, H(5)); 2.06 (s, 3 H,
C(10)H3); 2.15—2.30 (m, 3 H, H(1), H(4), H(7)); 2.58
(m, 1 H, H(7)b); 3.95 (s, 1 H, H(11)); 6.20 (d, 1 H, H(17),
J = 7.6 Hz); 6.55 (s, 1 H, OH); 6.91 (dd, 1 H, H(15), J = 7.4 Hz,
J = 7.8 Hz); 6.98 (d, 2 H, H arom., J = 7 Hz); 7.10 (dd,
1 H, H(16), J = 7.4 Hz, J = 7.6 Hz); 7.22—7.35 (m, 3 H,
H arom.); 7.60 (d, 1 H, H(14), J = 7.8 Hz). 13C NMR (CDCl3),
: 22.92 (C(9)), 27.13 (C(8)), 27.73 (C(10)), 28.86 (C(7)),
36.30 (C(4)), 38.00 (C(5)), 40.57 (C(6)), 51.65 (C(1)),
75.32 (C(11)), 88.39 (C(2)), 124.71 (C(15)), 124.83 (C(16)),
124.93 (C(17)), 127.68 (pꢀCPh), 127.82 (oꢀCPh), 128.93 (mꢀCPh),
135.85 (C(14)), 140.51 (CAr), 142.48 (C(12)), 157.49 (C(13)),
187.77 (C(3)).
transꢀDichlorobis[(1R,2S,4S)ꢀ3ꢀbenzyliminoꢀ1,7,7ꢀtrimethꢀ
ylbicyclo[2.2.1]heptanꢀ2ꢀolꢀN]palladium(II) (23). The yield was
20
80 mg (58%), m.p. 159—160 C (with decomp.), []D +138.9
(c 0.2, acetone), yellow powder soluble in acetone, benzene, and
DMSO, Rf 0.7 (benzene—acetone, 5 : 1). Found (%): C, 58.50;
H, 6.70; N, 3.55. C34H46Cl2N2O2Pd. Calculated (%): C, 59.00;
H, 6.60; N, 3.81. IR, /cm–1: 3456 (OH), 1638 (C=N).
1H NMR (DMSOꢀd6), : 0.73 (s, 3 H, C(10)H3); 0.74 (s, 3 H,
C(9)H3); 0.92 (s, 3 H, C(8)H3); 1.20 (m, 1 H, H(5)); 1.26 (m, 1 H,
H(6)); 1.47 (m, 1 H, H(6)); 1.78 (m, 1 H, H(5)); 2.09 (m, 1 H,
H(4)); 3.43 (d, 1 H, H(2), J = 7 Hz); 3.81 (d, 1 H, H(11´),
J = 12 Hz); 4.36 (d, 1 H, H(11), J = 12 Hz); 4.78 (br.d, 1 H,
OH, J = 7 Hz); 7.30—7.65 (m, 5 H, H arom.). 13C NMR
(DMSOꢀd6), : 10.06 (C(10)), 18.82 (C(8)), 19.87 (C(9)), 19.95
(C(5)), 30.37 (C(6)), 43.43 (C(1)), 47.82 (C(4)), 56.52 (C(11)),
59.74 (C(7)), 68.44 (C(2)), 127.92 (C(15)), 128.27 (C(14)),
130.76 (C(13)), 137.21 (C(12)), 214.88 (C(3)).
transꢀDichlorobis{(1S,4S)ꢀ2ꢀdiphenylmethyliminoꢀ1,7,7ꢀtriꢀ
methylbicyclo[2.2.1]heptaneꢀN}palladium(II) (20). The yield was
100 mg (82%), m.p. 169—170 C (with decomp.), []D +200
20
(c 0.03, CHCl3), orange powder soluble in acetone, benzene,
and DMSO, Rf 0.7 (benzene—acetone, 10 : 1). Found (%):
C, 67.80; H, 6.69; N, 3.37. C46H54Cl2N2Pd. Calculated (%):
C, 68.10; H, 6.65; N, 3.45. IR, /cm–1: 1622 (C=N). 1H NMR
(DMSOꢀd6), : 0.57 (s, 3 H, C(9)H3); 0.90 (s, 3 H, C(8)H3);
1.01 (s, 3 H, C(10)H3); 1.15 (m, 1 H, H(5)); 1.24 (m, 1 H,
H(6)); 1.67 (m, 1 H, H(6)); 1.75 (m, 1 H, H(5)); 1.80 (m, 1 H,
H(4)); 1.94 (d, 1 H, H(3), J = 17 Hz); 2.29 (m, 1 H, H(3),
J = 17 Hz); 5.52 (s, 1 H, H(11)); 7.15—7.45 (m, 10 H, H arom.).
13C NMR (DMSOꢀd6), : 12.02 (C(10)), 19.28 (C(8)),
19.62 (C(9)), 27.42 (C(5)), 32.12 (C(6)), 35.95 (C(3)), 43.73
(C(4)), 47.24 (C(7)), 54.00 (C(1)), 67.85 (C(11)), 126.80
(C(15)), 126.81 (C(15´)), 127.55 (C(13)), 127.60 (C(13´)), 128.60
(C(14)), 128.64 (C(14´)), 145.56 (C(12)), 145.68 (C(12´)),
197.26 (C(2)).
transꢀDichlorobis{(1R,2S,4S)ꢀ3ꢀ[(1S)ꢀꢀmethylbenzylimiꢀ
no]ꢀ1,7,7ꢀtrimethylbicyclo[2.2.1]heptanꢀ2ꢀolꢀN}palladium (II)
(24). The yield was 92 mg (64%), m.p. 162—163 C (with deꢀ
20
comp.), []D +94.4 (c 0.3, CHCl3), yellow powder soluble in
chloroform, acetone, benzene, and DMSO, Rf 0.8 (benzꢀ
ene—acetone, 5 : 1). Found (%): C, 60.60; H, 7.40; N, 4.61.
C36H50Cl2N2O2Pd. Calculated (%): C, 60.55; H, 6.99; N, 4.36.
IR, /cm–1: 3192 (OH), 1643 (C=N). 1H NMR (CDCl3),
: 0.89 (s, 3 H, C(9)H3); 0.91 (s, 3 H, C(10)H3); 1.07 (s, 3 H,
C(8)H3); 1.39 (m, 1 H, H(6)); 1.70 (d, 3 H, C(12)H3,
J = 7 Hz); 1.79 (m, 1 H, H(6)); 2.02 (m, 1 H, H(5)); 2.55
(m, 1 H, H(5)); 3.37 (dd, 1 H, H(4), J = 4.0 Hz, J = 4.2 Hz);
3.70 (d, 1 H, H(2), J = 4 Hz); 3.80 (br.s, 1 H, OH); 4.69
(q, 1 H, H(11), J = 7 Hz); 7.20—7.70 (m, 5 H, H arom.).
13C NMR (CDCl3), : 9.67 (C(10)), 18.78 (C(8)), 19.69 (C(9)),
20.37 (C(5)), 21.41 (C(12)), 31.91 (C(6)), 43.62 (C(1)),
50.49 (C(4)), 60.34 (C(7)), 60.99 (C(11)), 65.66 (C(2)), 128.02
(C(15)), 128.35 (C(16)), 129.90 (C(14)), 139.14 (C(13)),
216.15 (C(3)).
Diꢀꢀchlorobis{2ꢀ[((1S,4S)ꢀ1,7,7ꢀtrimethylbicyclo[2.2.1]ꢀ
heptꢀ2ꢀylideneamino)(phenyl)methyl]phenylꢀC,N}dipalladium(II)
(21). The yield was 90 mg (45%), m.p. 161—162 C (with deꢀ
comp.), []D20 +114.5 (c 0.2, CHCl3), yellow powder soluble in
chloroform, acetone, benzene, and DMSO, Rf 0.7 (benzꢀ
ene—acetone, 10 : 1). Found (%): C, 59.80; H, 5.75; N, 3.39.
C46H52Cl2N2Pd2. Calculated (%): C, 60.20; H, 5.68; N, 3.06.
IR, /cm–1: 1625 (C=N). H NMR (CDCl3), : 0.80 (s, 3 H,
1
C(9)H3); 0.99 (s, 3 H, C(8)H3); 1.07 (m, 1 H, H(5));
1.73—2.00 (m, 5 H, H(6), H(5), H(3), H(4), H(6)); 2.04
(s, 3 H, C(10)H3); 2.89 (dd, 1 H, H(3), J = 3.6 Hz, J = 17 Hz);
5.67 (s, 1 H, H(11)); 6.55 (br, 1 H, H(14)); 6.79 (br, 1 H, H(15));
6.92 (m, 1 H, pꢀHPh); 7.04 (m, 2 H, H(16), H(17)); 7.27 (m, 2 H,
mꢀHPh); 8.02 (d, 2 H, oꢀHPh, J = 7 Hz). 13C NMR (CDCl3),
: 13.16 (C(10)), 19.01 (C(8)), 20.17 (C(9)), 26.71 (C(5)), 31.35
(C(6)), 39.61 (C(3)), 43.14 (C(4)), 49.98 (C(7)), 55.80 (C(1)),
80.06 (C(11)), 121.06 (C(17)), 124.53 (C(16)), 125.23 (pꢀCPh),
126.68 (oꢀCPh), 126.95 (C(15)), 128.36 (C(14)), 134.54 (mꢀCPh),
140.13 (C(12), C(12´)), 151.11 (C(13)), 193.07 (C(2)).
This work was financially supported by the Ural Branch
of the Russian Academy of Sciences (Project No. 12ꢀUꢀ
3ꢀ1015).
Diꢀꢀchlorobis{2ꢀ[((1S,4S)ꢀ1,7,7ꢀtrimethylꢀ2ꢀoxobicycloꢀ
[2.2.1]heptꢀ3ꢀylideneamino)(phenyl)methyl]phenylꢀC,N}dipalꢀ
ladium(II) (22). The yield was 89 mg (54%), m.p. 167—168 C
(with decomp.), []D +28.7 (c 0.2, CHCl3), yellow powder
soluble in chloroform, acetone, benzene, and DMSO, Rf 0.7
References
20
1. J. Dupont, C. S. Consorti, J. Spencer, Chem. Rev., 2005,
105, 2527.

750
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 3, March, 2013
Kuchin et al.
2. V. V. Dunina, O. N. Gorunova, P. A. Zykov, K. A. Kochetꢀ
kov, Russ. Chem. Rev. (Engl. Transl.), 2011, 80, 51 [Usp. Khim.,
2011, 80, 53].
7. I. Fleming, R. B. Woodward, J. Chem. Soc. (C), 1968, 1289.
8. Ya. A. Gur´eva, O. A. Zalevskaya, L. L. Frolova, I. N. Alekꢀ
seev, A. V. Kuchin, Khim. Prirod. Soedin., 2010, 6, 783 [Chem.
Nat. Compd. (Engl. Transl.), 2011, 46, 920].
9. O. A. Zalevskaya, Ya. A. Gur´eva, L. L. Frolova, I. N. Alekꢀ
seev, P. A. Slepukhin, A. V. Kuchin, Koordinats. Khim.,
2013, 39, 41 [Russ. J. Coord. Chem. (Engl. Transl.), 2013,
39, 135].
3. O. A. Zalevskaya, Y. A. Gur´eva, L. L. Frolova, I. N. Alekꢀ
seev, A. V. Kutchin, Natural Science, 2010, 2, 1194.
4. Ya. A. Gur´eva, O. A. Zalevskaya, L. L. Frolova, I. N. Alekꢀ
seev, P. A. Slepukhin, A. V. Kuchin, Zh. Obshch. Khim., 2012,
82, 1117 [Russ. J. Gen. Chem. (Engl. Transl.), 2012, 82].
5. K. G. Carlson, J. K. Pierce, J. Org. Chem., 1971, 36, 2319.
6. K. Hattori, T. Yoshida, K. Rikuta, T. Miyakoshi, J. Chem.
Soc. Jpn, Chem. Lett., 1994, 1885.
Received December 19, 2012