Palladium-assisted formation of carbon-carbon bonds. 8. Synthesis and reactivity toward internal alkynes, carbon monoxide, and isocyanides of orthopalladated dibenzylamine complexes

Article abstract of DOI:10.1021/om990143y

By refluxing of dibenzylamine and [Pd(OAc)₂]₃ (3.2:1) in acetone, the orthometalated complex [Pd{C₆H₄(CH₂NHCH ₂Ph)-2}(μ-OAc)]₂ (1) is obtained. Metathetical reaction of 1 with NaBr affords the corresponding bromo-bridging dimer [Pd{C₆H₄(CH₂NHCH ₂Ph)-2}(μ-Br)]₂ (2). Neutral ligands split the bromo bridge to give monomeric complexes [Pd{C₆H₄(CH₂-NHCH₂Ph)-2}Br(L)] [L = PPh₃, (3a), NH(CH₂Ph)₂ (3b)]. Complexes [Pd{C₆H₄(CH₂NHCH₂-Ph)-2}(acac)] (4) or [Pd{C₆H₄(CH₂NHCH₂Ph)-2}L ₂]ClO₄ [L = py (5a), L₂ = 1,5-cyclooctadiene (5b)] can be obtained by reacting complex 2 with [Tl(acac)] or with AgClO₄ and the free ligand. Complex 2 reacts with RC≡CR (R = Me, Et, Ph) to give [Pd{C(R)=C(R)C(R)=C(R)-C₆H₄(CH₂NHCH ₂Ph)-2}Br] [R = Me (6a), Et (6b), Ph (6c)] through a double insertion of the alkyne into the Pd-C bond. Complex 6a reacts with Tl(OTf) (OTf = CF₃SO₃) and neutral ligands to give [Pd{C(R)=C(R)C(R)=C(R)C₆H₄(CH₂NHCH ₂Ph)-2}L]OTf [R = Me, L = py (7), phen (8)]. Complexes 6 insert CO or isocyanides R′NC into the C-Pd bond to give 10-membered palladacycles [Pd{C(R)=C(R)C(R)=C(R)C(E)C₆H₄(CH₂NHCH ₂Ph)-2}Br] [E = O, R = Me (9a), Et (9b), Ph (9c); E = NR′, R′ = ^tBu, R = Me (10a), Et (10b); R′ = C₆H₃-Me₂-2,6, R = Me (11a), Et (11b)]. Complex 9a reacts with Tl(OTf) and neutral ligands to give [Pd{C(=O)C(R)=C(R)C(R)=C(R)C₆H₄(CH₂NHCH ₂Ph)-2}L]OTf [R = Me, L = py (12), ^tBuNC (13), phen (14)]. The crystal structures of 2·CH₂Cl₂, 7, 9a, and 13 have been solved.

Full text of DOI:10.1021/om990143y

Organometallics 1999, 18, 2683-2693
2683
P a lla d iu m -Assisted F or m a tion of Ca r bon -Ca r bon Bon d s.
8.1 Syn th esis a n d Rea ctivity tow a r d In ter n a l Alk yn es,
Ca r bon Mon oxid e, a n d Isocya n id es of Or th op a lla d a ted
Diben zyla m in e Com p lexes
J ose´ Vicente,*,† Isabel Saura-Llamas, J uana Turp´ın, and
M. Carmen Ram´ırez de Arellano‡
Grupo de Quı´mica Organometa´lica,§ Departamento de Quı´mica Inorga´nica, Facultad de
Quı´mica, Universidad de Murcia, Apartado 4021, Murcia, 30071 Spain
Peter G. J ones|
Institut fu¨r Anorganische und Analytische Chemie, Technische Universita¨t Braunschweig,
Postfach 3329, 38023 Braunschweig, Germany
Received March 1, 1999
By refluxing of dibenzylamine and [Pd(OAc)2]3 (3.2:1) in acetone, the orthometalated
complex [Pd{C6H4(CH2NHCH2Ph)-2}(µ-OAc)]2 (1) is obtained. Metathetical reaction of 1 with
NaBr affords the corresponding bromo-bridging dimer [Pd{C6H4(CH2NHCH2Ph)-2}(µ-Br)]2
(2). Neutral ligands split the bromo bridge to give monomeric complexes [Pd{C6H4(CH2-
NHCH2Ph)-2}Br(L)] [L ) PPh3, (3a ), NH(CH2Ph)2 (3b)]. Complexes [Pd{C6H4(CH2NHCH2-
Ph)-2}(acac)] (4) or [Pd{C6H4(CH2NHCH2Ph)-2}L2]ClO4 [L ) py (5a ), L2 ) 1,5-cyclooctadiene
(5b)] can be obtained by reacting complex 2 with [Tl(acac)] or with AgClO4 and the free
ligand. Complex 2 reacts with RCtCR (R ) Me, Et, Ph) to give [Pd{C(R)dC(R)C(R)dC(R)-
C6H4(CH2NHCH2Ph)-2}Br] [R ) Me (6a ), Et (6b), Ph (6c)] through a double insertion of the
alkyne into the Pd-C bond. Complex 6a reacts with Tl(OTf) (OTf ) CF3SO3) and neutral
ligands to give [Pd{C(R)dC(R)C(R)dC(R)C6H4(CH2NHCH2Ph)-2}L]OTf [R ) Me, L ) py (7),
phen (8)]. Complexes 6 insert CO or isocyanides R′NC into the C-Pd bond to give
10-membered palladacycles [Pd{C(R)dC(R)C(R)dC(R)C(E)C6H4(CH2NHCH2Ph)-2}Br] [E )
t
O, R ) Me (9a ), Et (9b), Ph (9c); E ) NR′, R′ ) Bu, R ) Me (10a ), Et (10b); R′ ) C6H3-
Me2-2,6, R ) Me (11a ), Et (11b)]. Complex 9a reacts with Tl(OTf) and neutral ligands to
give [Pd{C(dO)C(R)dC(R)C(R)dC(R)C6H4(CH2NHCH2Ph)-2}L]OTf [R ) Me, L ) py (12),
tBuNC (13), phen (14)]. The crystal structures of 2‚CH2Cl2, 7, 9a , and 13 have been solved.
In tr od u ction
The orthopalladation of aliphatic amines was initially
reported to fail for primary and secondary amines.33
Interest in orthometalated complexes arises from
their potential application in organic synthesis,2-8 in
catalysis,9-15 as chiral resolving agents,16-27 as drugs,28
and as new materials.29-32
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† E-mail: jvs@fcu.um.es.
‡ Corresponding author regarding the X-ray diffraction studies of
complexes 2 and 9a . E-mail: mcra@fcu.um.es.
§ WWW: http://www.scc.um.es/gi/gqo/.
| Corresponding author regarding the X-ray diffraction studies of
complexes 7 and 13. E-mail: jones@xray36.anchem.nat.tu-bs.de.
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10.1021/om990143y CCC: $18.00 © 1999 American Chemical Society
Publication on Web 06/15/1999

2684 Organometallics, Vol. 18, No. 14, 1999
Vicente et al.
Thus, orthopalladation using lithium tetrachloropalla-
date(II) was observed with N,N-dimethylbenzylamine
or some of its aryl-substituted derivatives containing
electron-releasing groups (2-methoxy, 3,5-dimethoxy)
but did not occur, for example, with L ) benzylamine,
dibenzylamine, and N-methyl- or N-phenylbenzylamine;
these reactions led to the adducts [PdCl2L2]. However,
using different palladium reagents and/or experimental
reaction conditions, it has been demonstrated that
benzylamine, and some of its secondary amine deriva-
tives, can be orthometalated.34-46 In this paper, we
describe for the first time the orthopalladation of
dibenzylamine and the synthesis of some derivatives of
the resulting product.
Insertion reactions of alkynes into the metal-carbon
bond of orthopalladated complexes and, in particular,
those derived from tertiary benzylamines have been
widely studied (mainly by Pfeffer).2-5,47-57 We have
reported the only study devoted to reactions of alkynes
with an orthopalladated primary benzylamine.58 As far
as we are aware, Heck has reported the only known
example of a reaction between an orthopalladated
secondary amine and one acetylene.57 In this paper, we
give account of the first study of the reactivity of a
cyclopalladated secondary amine (dibenzylamine) with
various alkynes.
The insertion reactions of alkynes into the pal-
ladium-carbon bond are interesting processes that have
been used, after depalladation,2-4 to prepare spiro-
cyclic compounds,59,60 indenols, indenones,61 carbocy-
cles,47,54,56,57,60,62,63 and oxygen,50,64,65 sulfur,5,66,67 and
nitrogen heterocycles.49,50,55,63,64,68-73 In some cases, the
palladation reaction and the insertion of the alkyne form
part of a catalytic cycle yielding interesting organic
compounds.57,74-85 Recently, Negishi has reported the
reaction of 4-octyne with PhI and CO (10-40 atm) in
the presence of Et3N and catalytic amounts of [PdCl2-
(PPh3)2] at 100-140 °C to give 2-butenolides.82 These
compounds are formed through a sequential insertion
of carbon monoxide-alkyne-carbon monoxide. In this
paper we report the isolation of products resulting from
the sequential insertion of alkyne and carbon monoxide
at atmospheric pressure and temperature into the aryl-
Pd bond. As far as we are aware, the only precedent for
such reaction is that between CO and the diinserted
product of the reaction of orthopalladated dimethylben-
zylamine with 3-hexyne, although it was performed at
50 °C and 25 psi.57
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Palladium-Assisted Formation of Carbon-Carbon Bonds
Organometallics, Vol. 18, No. 14, 1999 2685
Chemical shifts are referred to TMS [1H and 13C{1H}] or H3-
PO4 [31P{1H}]. Reactions were carried out at room temperature
without special precautions against moisture. Wa r n in g: Per-
chlorate salts may be explosive!
Ω-1 cm2 mol-1 (5.50 × 10-4 mol L-1). Anal. Calcd for C28H29
-
BrN2Pd (579.9): C, 58.00; H, 5.04; N, 4.83. Found: C, 57.48;
H, 4.83; N, 4.82. IR (Nujol, cm-1): ν(NH) ) 3240. 1H NMR
(CDCl3): δ ) 3.20 (m, 1H, NH), 3.48 (m, 2H, CH2), 3.90-4.16
(m, 5H, CH2 and NH), 4.62 (m, 2H, CH2), 6.21 (d, 1H, C6H4,
3J HH ) 7.2 Hz), 6.77-6.93 (m, 3H, C6H4), 7.31-7.73 (m, 15H,
C6H5).
Solvents and reagents were purified as follows: acetone,
distilled from KMnO4; ether, distilled from Na/benzophenone;
CH2Cl2, distilled from P2O5 and then from Na2CO3; n-hexane,
distilled from CaCl2. Dibenzylamine, 3-hexyne (Aldrich), 2-bu-
tyne, diphenylacetylene, and triphenylphosphine (Fluka) and
[Pd(OAc)2]3 (J ohnson Matthey) were used as received.
Syn th esis of [P d {C6H4(CH2NHCH2P h )-2}(µ-OAc)]2 (1).
Dibenzylamine (2 mL, 10.40 mmol) and [Pd(OAc)2]3 (2.2 g, 3.27
mmol) were refluxed in acetone (20 mL) for 2 h. Complex 1
precipitated as a dark yellow solid, which was collected,
washed with diethyl ether (3 × 15 mL), and air-dried. Yield:
3.2 g, 4.42 mmol, 90%. Mp: 160-161 °C. Anal. Calcd for
Syn th esis of [P d {C6H4(CH2NHCH2P h )-2}(a ca c)] (4). To
a solution of complex 2 (350 mg, 0.457 mmol) in CH2Cl2 (50
mL) was added solid [Tl(acac)] (278 mg, 0.915 mmol), with
stirring for 8 h. The resulting precipitate was removed by
filtration through a plug of Celite. The solvent was removed
to ca. 2 mL, and diethyl ether was added (25 mL) to obtain
complex 4 as a white solid which was collected, washed with
diethyl ether, and air-dried. Yield: 293 mg, 0.729 mmol, 80%.
Mp: 209-211 °C. ΛM ) 0 Ω-1 cm2 mol-1 (1.02 × 10-3 mol L-1).
Anal. Calcd for C19H21NO2Pd (401.8): C, 56.80; H, 5.27; N,
3.49. Found: C, 56.88; H, 5.20; N, 3.48. IR (Nujol, cm-1): ν-
C
32H34N2O4Pd2 (723.4): C, 53.13; H, 4.74; N, 3.87. Found: C,
53.19; H, 4.80; N, 4.01. IR (Nujol, cm-1): ν(NH) ) 3166.
Syn th esis of [P d {C6H4(CH2NHCH2P h )-2}(µ-Br )]2 (2). To
a suspension of complex 1 (1010 mg, 1.397 mmol) in acetone
(40 mL) was added solid NaBr (1000 mg, 9.718 mmol) and the
resulting mixture stirred for 6 h. The solvent was removed,
and the residue was taken up in CH2Cl2 (100 mL); the solution
was filtered through a plug of MgSO4 and concentrated to ca.
5 mL. Complex 2 precipitated as a bright yellow solid, which
was collected and air-dried. Yield: 840 mg, 1.10 mmol, 78%.
Mp: 113-114 °C. ΛM ) 2 Ω-1 cm2 mol-1 (5.23 × 10-4 mol L-1).
Anal. Calcd for C28H28Br2N2Pd2 (765.2): C, 43.95; H, 3.69; N,
3.66. Found: C, 44.07; H, 3.71; N, 3.63. IR (Nujol, cm-1): ν-
(NH) ) 3200. 1H NMR ([D6]acetone): δ ) 3.95 (d, 2H, CH2,
1
(NH) ) 3175. H NMR (CDCl3): δ ) 1.95 (s, 3H, Me), 2.06 (s,
3H, Me), 3.74 and 3.95 (AB part of an ABX system, 2H, CH2,
3
3
2J AB ) 14 Hz, J AX ) 12 Hz, J BX ) 3 Hz), 3.99 (dd, 1H, CH2,
2J HH ) 13.5 Hz, J HH ) 10.5 Hz), 4.26 (m, 1H, NH), 4.52 (dd,
1H, CH2, J HH ) 3 Hz), 5.34 (s, 1H, CH), 6.78 (m, 1H, C6H4),
3
3
6.96 (m, 2H, C6H4), 7.31-7.44 (m, 1H of C6H4 and 5H of Ph).
13C{1H}NMR: δ ) 27.8, 28.2 (s, Me), 56.6, 60.2 (s, CH2), 100.2
(s, CH), 120.6, 124.4, 124.9, 128.5 (s, CH, C6H4 or Ph), 129.1
(s, CH, Ph), 129.4 (s, CH, Ph), 130.8 (s, CH, C6H4 or Ph), 135.6,
145.6, 147.5 (s, C, Ph or C6H4), 186.7, 187.9 (s, CO).
2
3
3J HH ) 6.0 Hz), 4.10 (dd, 1H, CH2, J HH ) 13.5 Hz, J HH
)
Syn th esis of [P d{C6H4(CH2NHCH2P h )-2}(py)2]ClO4 (5a).
To a solution of complex 2 (115 mg, 0.150 mmol) in acetone
(20 mL) was added solid AgClO4 (70 mg, 0.30 mmol), and the
mixture was left to stand for 30 min. The resulting precipitate
of silver chloride was then removed by filtration through a plug
of MgSO4; pyridine (0.05 mL, 0.5 mmol) was added, and the
resulting colorless solution was stirred for 6 h and then filtered
again through MgSO4. The solvent was removed to ca. 2 mL,
and diethyl ether was added (25 mL) to precipitate complex
5a as a white solid, which was collected, washed with diethyl
ether, and air-dried. Yield: 109 mg, 0.195 mmol, 65%. Mp:
190-191. °C. ΛM ) 107 Ω-1 cm2 mol-1 (5.71 × 10-4 mol L-1).
Anal. Calcd for C24H24ClN3O4Pd (560.4): C, 51.45; H, 4.32; N,
7.50. Found: C, 51.75; H, 4.35; N, 7.65. IR (Nujol, cm-1): ν-
3
10.0 Hz), 4.56 (dd, 1H, CH2, J HH ) 3.0 Hz), 5.86 (s, b, 1H,
NH), 6.73-6.91 (m, 3H, C6H4 and Ph), 7.29-7.44 (m, 4H, C6H4
and Ph), 7.60-7.63 (d, 2H, Ph). 13C{1H} NMR ([D6]acetone):
δ ) 58.5 (s, CH2), 60.1 (s, CH2), 122.2 (s, CH, C6H4), 125.1 (s,
CH, C6H4), 125.6 (s, CH, C6H4), 125.5 (s, CH, C6H4), 129.0 (s,
p-CH, Ph), 129.5 (s, o-CH or m-CH, Ph), 130.4 (s, o-CH or
m-CH, Ph), 135.6 (s, CH, C6H4), 136.7 (s, i-C, Ph), 146.0 (s, C,
C6H4), 149.8 (s, C, C6H4).
Syn th esis of [P d{C6H4(CH2NHCH2P h )-2}Br (P P h 3)] (3a).
To a suspension of complex 2 (41 mg, 0.053 mmol) in acetone
(25 mL) was added solid PPh3 (29 mg, 0.11 mmol). The
resulting solution was stirred for 1 h and then filtered through
a plug of MgSO4. The solvent was removed to ca. 2 mL, and
diethyl ether (25 mL) was added to precipitate complex 3a as
a pale yellow solid, which was collected and air-dried. Yield:
42 mg, 0.065 mmol, 61%. Mp: 214-215 °C (dec). ΛM ) 0 Ω-1
cm2 mol-1 (6.53 × 10-4 mol L-1). Anal. Calcd for C32H29BrNPPd
(644.9): C, 59.60; H, 4.53; N, 2.17. Found: C, 59.69; H, 4.55;
1
2
(NH) ) 3220. H NMR (CDCl3): δ ) 3.81 (dd, 1H, CH2, J HH
3
) 11.7 Hz, J HH ) 9.6 Hz), 4.00 (m, 2H, CH2), 4.85 (dd, 1H,
2
3
CH2, J HH ) 14.7 Hz, J HH ) 4.8 Hz), 5.48 (s, b, 1H, NH), 6.03
(d, 1H, C6H4, 3J
) 6.9 Hz), 6.78 (m, 1H, C6H4), 7.01 (m, 2H,
HH
1
C6H4), 7.19-7.30 (m, 5H, Ph), 7.19-7.45 (m, 4H, m-py), 7.60
(m, 1H, p-py), 7.89 (m, 1H, p-py), 8.08 (m, 2H, o-py), 8.72 (m,
2H, o-py). 13C{1H}NMR: δ ) 58.4 (s, CH2), 62.3 (s, CH2), 122.7
(s, CH, C6H4), 125.3, 125.6 (s, m-py), 126.5 (s, CH, Ph), 128.6
(s, CH, Ph), 129.0 (s, CH, Ph), 129.9 (s, p-py), 132.5 (s, CH,
C6H4), 136.4 (s, C, Ph), 137.9 (s, CH, C6H4), 139.1 (s, CH, C6H4),
147.1 (s, C, C6H4), 149.4 (s, C, C6H4), 149.7, 151.9 (s, o-py).
N, 2.19. IR (Nujol, cm-1): ν(NH) ) 3280. H NMR (CDCl3): δ
) 3.80 (m, 3H, CH2), 4.61 (m, 3H, NH and CH2), 4.13 (m, 1H,
3
NH), 6.34 (t, 1H, H4 or H5, C6H4, J HH ) 7.2 Hz), 6.43 (t, 1H,
H4 or H5, C6H4), 6.86 (t, 1H, H6, C6H4, 3J HH ) 4J HP ) 7.2 Hz),
7.04 (d, 1H, H3), 7.25-7.46 (m, 9H, Ph), 7.70-7.77 (m, 6H,
Ph). 13C{1H}NMR (CDCl3): δ ) 54.0 (d, CH2, J PC ) 2.0 Hz),
57.3 (d, CH2, J PC ) 3.0 Hz), 122.9 (s, CH, C6H4), 124.1 (s, CH,
C6H4), 125.0 (d, CH, C6H4, J PC ) 5.1 Hz), 128.0 (d, o-CH, PPh3,
J PC ) 11.1 Hz), 128.1 (s, CH, C6H5), 128.9 (s, CH, C6H5), 129.5
(s, CH, C6H5), 130.6 (d, p-CH, PPh3, J PC ) 2.6 Hz), 131.5 (d,
i-CH, PPh3, J PC ) 49.3 Hz), 135.2 (d, m-CH, PPh3, J PC ) 11.6
Hz), 136.3 (s, C, C6H5), 137.5 (d, CH, C6H4, J PC ) 10.6 Hz),
150.2 (d, C, C6H4, J PC ) 1.1 Hz), 153.0 (s, C, C6H4). 31P{1H}
NMR (CDCl3): δ ) 42.1 (s).
Syn t h esis of [P d {C6H 4(CH2NH CH2P h )-2}(COD)]ClO4
(5b). To a solution of complex 2 (95 mg, 0.12 mmol) in acetone
(30 mL) was added solid AgClO4 (51 mg, 0.25 mmol), and the
mixture was left to stand for 30 min. The resulting precipitate
of silver chloride was then removed by filtration through a plug
of MgSO4; COD (0.05 mL, 0.3 mmol) was added, and the
resulting colorless solution was stirred for 6h and then filtered
again through MgSO4. The solvent was removed to ca. 2 mL,
and diethyl ether was added (25 mL) to precipitate complex
5b as a white solid, which was collected, washed with diethyl
ether, and air-dried. Yield: 105 mg, 0.206 mmol, 86%. Mp:
186-188 °C. ΛM ) 91 Ω-1 cm2 mol-1 (1.00 × 10-3 mol L-1).
Anal. Calcd for C22H26ClNO4Pd (510.3): C, 51.78; H, 5.14; N,
2.74. Found: C, 51.78; H, 5.30; N, 2.76. IR (Nujol, cm-1): ν-
Syn th esis of [P d {C6H4(CH2NHCH2P h )-2}Br {(NH(CH2-
P h )2}] (3b). To a suspension of complex 2 (123 mg, 0.161
mmol) in CH2Cl2 (20 mL) was added benzylamine (60 µL, 0.32
mmol). The resulting solution was stirred for 4 h and then
filtered through a plug of MgSO4. The solvent was removed
to ca. 2 mL, and n-hexane (25 mL) was added to precipitate
complex 3b as a yellow solid, which was collected and air-dried.
Yield: 142 mg, 0.245 mmol, 76%. Mp: 124-125 °C. ΛM ) 0

2686 Organometallics, Vol. 18, No. 14, 1999
Vicente et al.
1
(NH) ) 3185. H NMR (CDCl3): δ ) 1.82 (m, 1H, CH2, COD),
h and then filtered through MgSO4. The solvent was removed
to ca. 2 mL, and diethyl ether (25 mL) was added to precipitate
complex 7 as a pale yellow solid, which was collected and air-
2.28 (m, 1H, CH2, COD), 2.68 (m, 6H, CH2, COD), 3.85 (dd,
1H, CH2, 2J HH ) 12 Hz, 3J HH ) 10 Hz), 4.01 (dd, 1H, CH2, 2J HH
3
) 15 Hz, J HH ) 1.0 Hz), 4.21 (m, 1H of CH2 and NH), 4.86
dried. Yield: 77 mg, 0.12 mmol, 60%. Mp: 174-176 °C. ΛM )
2
3
(dd, 1H, CH2, J HH ) 15 Hz, J HH ) 4.8 Hz), 5.79 (m, 2H, CH,
COD), 6.29 (m, 1H, CH, COD), 6.41 (m, 1H, CH, COD), 6.76
(d, 1H, C6H4), 7.05 (m, 2H, C6H4), 7.12-7.20 (m, 2H, C6H4),
7.42-7.50 (m, 3H, Ph), 7.59-7.63 (m, 2H, Ph). 13C{1H}NMR:
δ ) 27.5, 28.7, 29.3, 30.0 (s, CH2, COD), 58.5, 61.6 (s, CH2),
109.4, 111.2 (s, CH, COD), 120.9 (s, CH, C6H4), 124.3, 124.9
(s, CH, COD), 126.8, 127.4, 129.3 (s, CH, C6H4 or Ph), 129.5,
130.0 (s, CH, Ph), 131.1 (s, CH, C6H4 or Ph), 136.0 (s, C, Ph),
149.8, 150.1 (s, C, C6H4).
118 Ω-1 cm2 mol-1 (5 × 10-4 mol L-1). Anal. Calcd for
C
28H31F3N2O3PdS (639.0): C, 52.63; H, 4.89; N, 4.38; S, 5.02.
Found: C, 52.32; H, 5.04; N, 4.45; S, 4.80. IR (Nujol, cm-1):
ν(NH) ) 3221. 1H NMR (CDCl3, -60 °C): δ ) 1.09 (s, 3H, Me),
1.81 (s, 3H, Me), 2.16 (s, 3H, Me), 2.17 (s, 3H, Me), 2.81
(apparent triplet, 1H, NH), 3.53 (apparent doublet, 1H, CH2),
4.11 (apparent doublet, 1H, CH2), 4.27 (apparent doublet, 1H,
CH2), 4.72 (apparent doublet, 1H, CH2), 6.68 (d, 1H, o-py, 3J HH
) 5.1 Hz), 6.89 (apparent triplet, 1H, m-py), 7.12-7.54 (m,
10H, C6H4 and Ph and p-py), 7.71 (apparent triplet, 1H, m-py),
8.83 (d, 1H, o-py, J HH ) 5.1 Hz).
Syn th esis of [P d {C(R)dC(R)C(R)dC(R)C6H4(CH2NH-
CH2P h )-2}Br ] [R ) Me (6a )]. To a suspension of complex 2
(400 mg, 0.523 mmol) in CH2Cl2 (20 mL) was added MeCt
CMe (300 µL, 3.82 mmol). After 8 h, a dark yellow solution
was formed, which was filtered through a plug of MgSO4. The
solvent was removed to ca. 2 mL, and n-pentane (25 mL) was
added to precipitate complex 6a as a yellow solid, which was
collected and air-dried. Yield: 306 mg, 0.624 mmol, 60%. Mp:
154-156 °C. ΛM ) 0 Ω-1 cm2 mol-1 (7.80 × 10-4 mol L-1). Anal.
Calcd for C22H26BrNPd (490.7): C, 53.84; H, 5.34; N, 2.85.
Found: C, 53.69; H, 5.38; N, 2.75. IR (Nujol, cm-1): ν(NH) )
Syn th esis of [P d {C(R)dC(R)C(R)dC(R)C6H4(CH2NH-
CH2P h )-2}(p h en )]OTf [R ) Me (8)]. To a solution of complex
6a (115 mg, 0.234 mmol) in acetone (15 mL) was added Tl-
(OTf) (85 mg, 0.24 mmol), and the mixture was stirred for 20
min; 1,10-phenanthroline monohydrate (47 mg, 0.24 mmol)
was added, and the resulting yellow suspension was stirred
for 1 h and then filtered through MgSO4. The solvent was
removed to ca. 1 mL, and diethyl ether (25 mL) was added to
precipitate complex 8 as a bright yellow solid, which was
collected and air-dried. Yield: 130 mg, 0.176 mmol, 75%. Mp:
164-166 °C. ΛM ) 122 Ω-1 cm2 mol-1 (5.9 × 10-4 mol L-1).
Anal. Calcd for C35H34F3N3O3PdS (739.7): C, 56.78; H, 4.63;
N, 5.68; S, 4.33. Found: C, 56.61; H, 4.68; N, 5.78; S, 4.33. IR
(Nujol, cm-1): ν(NH) ) 3245. 1H NMR (CDCl3): δ ) 1.03 (s,
3H, CH3), 1.57 (s, 3H, CH3), 1.65 (s, 3H, CH3), 1.76 (s, 3H,
3202. 1H NMR (CDCl3): δ ) 1.81 (s, 3H, Me), 1.85 (s, 3H, Me),
2
2.10 (s, 3H, Me), 2.12 (s, 3H, Me), 2.87 (dd, 1H, CH2, J HH
)
13.8 Hz, 3J HH ) 12.3 Hz), 3.40 (m, 1H, NH), 3.47 (dd, 1H, CH2,
2J HH ) 13.0 Hz, J HH ) 2 Hz), 4.04 (dd, 1H, CH2, J HH ) 13.5
3
2
3
3
Hz, J HH ) 2 Hz), 4.18 (dd, 1H, CH2, J HH ) 3 Hz), 7.10-7.45
(m, 9H, C6H4 and Ph).
2
CH3), 2.83 (m, 1H, NH), 4.43 (dd, 1H, CH2, J HH ) 12.3 Hz,
Syn th esis of [P d {C(R)dC(R)C(R)dC(R)C6H4(CH2NH-
CH2P h )-2}Br ] [R ) Et (6b)]. To a suspension of complex 2
(200 mg, 0.261 mmol) in CH2Cl2 (20 mL) was added EtCtCEt
(180 µL, 1.57 mmol). After 6 h, a dark yellow solution was
formed, which was filtered through a plug of MgSO4. The
solvent was removed to ca. 2 mL, and n-hexane (25 mL) was
added to precipitate complex 6b as a yellow solid, which was
collected and air-dried. Yield: 165 mg, 0.302 mmol, 58%. Mp:
145 °C. ΛM ) 0 Ω-1 cm2 mol-1 (6.90 × 10-4 mol L-1). Anal.
Calcd for C26H34BrNPd (546.9): C, 57.10; H, 6.27; N, 2.56.
Found: C, 59.92; H, 6.34; N, 2.61. IR (Nujol, cm-1): ν(NH) )
3J HH ) 5.4 Hz), 4.48 and 4.67 (AB part of ABX system, 2H,
2
3
3
CH2, J AB ) 12 Hz, J AX ) 17 Hz, J BX ) 10 Hz), 4.74 (dd, 1H,
2
3
CH2, J HH ) 12.3 Hz, J HH ) 4 Hz), 7.05 (m, 2H, C6H4), 7.19
(m, 1H, C6H4), 7.27-7.41 (m, 6H, C6H4 and C6H5), 7.90 (dd,
3
3
1H, H3, phen, J HH ) 4.8 Hz, J HH ) 8.1 Hz), 8.11 (s, 2H, H5,
3
3
phen), 8.42 (dd, 1H, H3, phen, J HH ) 4.8 Hz, J HH ) 8.1 Hz),
4
3
8.55 (dd, 1H, H2, phen, J HH ) 1.2 Hz, J HH ) 5.4 Hz), 8.67
4
3
(dd, 1H, H4, phen, J HH ) 1.2 Hz, J HH ) 8.4 Hz), 8.71 (dd,
4
3
1H, H4, phen, J HH ) 1.2 Hz, J HH ) 8.4 Hz), 9.59 (dd, 1H,
4
3
H2, phen, J HH ) 1.2 Hz, J HH ) 4.8 Hz).
1
3
3245. H NMR (CDCl3): δ ) 1.01 (t, 3H, Me, J HH ) 7.5 Hz),
Syn t h esis of [P d {C(dO)C(R )dC(R )C(R )dC(R )C6H 4-
(CH2NHCH2P h )-2}Br ] [R ) Me (9a )]. CO was bubbled
through a solution of complex 6a (250 mg, 0.509 mmol) in CH2-
Cl2 (30 mL) for 1.5 h. After 8 h of stirring, the solution was
filtered through a plug of MgSO4. The solvent was removed
to ca. 2 mL, and diethyl ether (25 mL) was added to precipitate
complex 9a as a yellow solid, which was collected and air-dried.
Yield: 190 mg, 0.366 mmol, 72%. Mp: 187-188 °C. ΛM ) 0
3
3
1.07 (t, 3H, Me, J HH ) 7.5 Hz), 1.17 (t, 3H, Me, J HH ) 7.5
Hz), 1.34 (t, 3H, Me, 3J HH ) 7.5 Hz), 1.91 (m, 2H, Et), 2.14 (m,
1H, Et), 2.39 (m, 4H, Et), 2.60 (m, 1H, Et), 2.77 (apparent t,
2
3
1H, CH2, J HH ) J HH ) 13.0 Hz), 3.38 (m, 1H, NH), 3.38 (d,
2
2
1H, CH2, J HH ) 13.0 Hz), 4.07 (dd, 1H, CH2, J HH ) 13.5 Hz,
3J HH ) 1.5 Hz), 4.14 (dd, 1H, CH2, J HH ) 13.5 Hz, J HH ) 3.0
2
3
Hz), 7.07-7.46 (m, 9H, C6H4 and Ph).
Ω-1 cm2 mol-1 (6.20 × 10-4 mol L-1). Anal. Calcd for C23H26
-
Syn th esis of [P d {C(R)dC(R)C(R)dC(R)C6H4(CH2NH-
CH2P h )-2}Br ] [R ) P h (6c)]. To a suspension of complex 2
(100 mg, 0.131 mmol) in CH2Cl2 (25 mL) was added PhCt
CPh (187 mg, 1.04 mmol). After 12 h, a yellow solution was
formed, which was filtered through a plug of MgSO4. The
solvent was removed to ca. 2 mL, and diethyl ether (25 mL)
was added to precipitate complex 6c as a bright yellow solid,
which was collected and air-dried. Yield: 130 mg, 0.176 mmol,
67%. Mp: 175-176 °C. ΛM ) 0 Ω-1 cm2 mol-1 (5.68 × 10-4 mol
L-1). Anal. Calcd for C42H34BrNPd (739.0): C, 68.25; H, 4.64;
N, 1.89. Found: C, 67.97; H, 4.53; N, 2.02. IR (Nujol, cm-1):
BrNOPd (518.8): C, 53.25; H, 5.05; N, 2.70. Found: C, 53.14;
H, 4.95; N, 2.68. IR (Nujol, cm-1): ν(NH) ) 3225, ν(CO) ) 1675.
1H NMR (CDCl3): δ ) 1.68 (s, 3H, Me), 1.76 (s, 3H, Me), 2.11
2
(s, 3H, Me), 2.15 (s, 3H, Me), 2.73 (apparent t, 1H, CH2, J
HH
) 3J HH ) 13.0 Hz), 3.52 (d, 1H, CH2, 2J HH ) 13.0 Hz), 3.66 (m,
1H, NH), 4.03 (d, 1H, CH2, 2J HH ) 13.0 Hz), 4.31 (dd, 1H, CH2,
3
2J HH ) 13.0 Hz, J HH ) 3 Hz), 7.07-7.46 (m, 9H, C6H4 and
Ph).
Syn t h esis of [P d {C(dO)C(R )dC(R )C(R )dC(R )C6H 4-
(CH2NHCH2P h )-2}Br ] [R ) Et (9b)]. CO was bubbled
through a solution of complex 6b (160 mg, 0.293 mmol) in CH2-
Cl2 (30 mL) for 1.5 h. After 8 h of stirring, the solution was
filtered through a plug of MgSO4. The solvent was removed
to ca. 2 mL, and diethyl ether (25 mL) was added to precipitate
complex 9b as a yellow solid, which was collected and air-dried.
Yield: 160 mg, 0.278 mmol, 95%. Mp: 178-180 °C. ΛM ) 0
1
2
ν(NH) ) 3215. H NMR (CDCl3): δ ) 2.70 (dd, 1H, CH2, J HH
3
2
) 13.5 Hz, J HH ) 3 Hz), 3.22 (dd, 1H, CH2, J HH ) 13.5 Hz,
3J HH ) 2 Hz), 3.35 (t, 1H, CH2, J HH ) J HH ) 12.9 Hz), 3.55
2
3
2
(m, 1H, NH), 4.45 (d, 1H, CH2, J HH ) 12.9 Hz), 6.70-7.70
(m, 29H, C6H4 and Ph).
Syn th esis of [P d {C(R)dC(R)C(R)dC(R)C6H4(CH2NH-
CH2P h )-2}(p y)]OTf [R ) Me (7)]. To a solution of complex
6a (100 mg, 0.204 mmol) in acetone (15 mL) was added Tl-
(OTf) (OTf ) CF3SO3) (73 mg, 0.20 mmol), and the mixture
was stirred for 20 min. Pyridine (0.1 mL, 1.00 mmol) was
added, and the resulting yellow suspension was stirred for 6
Ω-1 cm2 mol-1 (5.56 × 10-4 mol L-1). Anal. Calcd for C27H34
-
BrNOPd (574.9): C, 56.41; H, 5.96; N, 2.44. Found: C, 56.46;
H, 6.09; N, 2.45. IR (Nujol, cm-1): ν(NH) ) 3215, ν(CO) ) 1680.
1H NMR (CDCl3): δ ) 1.06 (t, 3H, Me, 3J HH ) 7.5 Hz), 1.08 (t,
3
3
3H, Me, J HH ) 7.5 Hz), 1.26 (t, 3H, Me, J HH ) 7.5 Hz), 1.49

Palladium-Assisted Formation of Carbon-Carbon Bonds
Organometallics, Vol. 18, No. 14, 1999 2687
3
(t, 3H, Me, J HH ) 7.5 Hz), 1.77 (m, 2H, Et), 2.16 (m, 3H, Et),
3H, Me), 2.12 (s, 3H, Me), 2.16 (s, 3H, Me), 2.26 (s, 3H,
2
2.43 (m, 2H, Et), 2.72 (m, 1H of Et and 1H of CH2), 3.35 (m,
MeC6H3), 2.68 (s, 3H, MeC6H3), 2.70 (d, 1H, CH2, J HH ) 13.2
2
1H, NH), 3.44 (d, 1H, CH2, J HH ) 13.0 Hz), 3.97 (d, 1H, CH2,
Hz), 3.29 (m, 1H, NH), 3.47 (d, 1H, CH2, 2J HH ) 12.3 Hz), 3.88
(d, 1H, CH2, 2J HH ) 13.2 Hz), 4.10 (d, 1H, CH2, 2J HH ) 12 Hz),
7.09-7.53 (m, 12H, C6H3, C6H4 and Ph).
2J HH ) 13.0 Hz), 4.23 (dd, 1H, CH2, J HH ) 13.0 Hz, J HH
)
2
3
3.6 Hz), 7.13-7.47 (m, 9H, C6H4 and Ph).
Syn t h esis of [P d {C(dO)C(R )dC(R )C(R )dC(R )C6H 4-
(CH2NHCH2P h )-2}Br ] [R ) P h (9c)]. CO was bubbled
through a solution of complex 6c (111 mg, 0.150 mmol) in CH2-
Cl2 (30 mL) for 1.5 h. After 8 h of stirring, the solution was
filtered through a plug of MgSO4. The solvent was removed
to ca. 2 mL, and a mixture of diethyl ether/n-hexane (1:1, 25
mL) was added to precipitate complex 9c as a yellow solid,
which was collected and air-dried. Yield: 80 mg, 0.104 mmol
70%. Mp: 205 °C. ΛM ) 0 Ω-1 cm2 mol-1 (5.20 × 10-4 mol L-1).
Anal. Calcd for C43H34BrNOPd (567.1): C, 67.33; H, 1.82; N,
4.47. Found: C, 67.68; H, 1.89; N, 4.51. IR (Nujol, cm-1): ν-
Syn th esis of [P d {C(dNC6H3Me2-2,6)C(R)dC(R)C(R)d
C(R)C6H4(CH2NHCH2P h )-2}Br ] [R ) Et (11b)]. To a solu-
tion of complex 6b (100 mg, 0.183 mmol) in CH2Cl2 (15 mL)
was added 2,6-Me2C6H3NC (24 mg, 0.183 mmol). After 9 h, a
yellow solution was formed, which was filtered through a plug
of MgSO4. The solvent was removed to ca. 2 mL, and n-hexane
(25 mL) was added to precipitate complex 11b as a yellow solid,
which was collected, washed with n-hexane, and air-dried.
Yield: 100 mg, 0.147 mmol, 81%. Mp: 160-162 °C. ΛM ) 0
Ω-1 cm2 mol-1 (5.69 × 10-4 mol L-1). Anal. Calcd for C35H43
-
BrN2Pd (678.1): C, 61.99; H, 6.39; N, 4.13. Found: C, 61.55;
1
(NH) ) 3205, ν(CO) ) 1700. H NMR (CDCl3): δ ) 2.70 (dd,
H, 6.10; N, 4.10. IR (Nujol, cm-1): ν(NH) ) 3240. 1H NMR
2
3
3
1H, CH2, J HH ) 14.1 Hz, J HH ) 2.7 Hz), 3.23 (dd, 1H, CH2,
(CDCl3, -60 °C): δ ) 0.76 (t, 3H, Me, J HH ) 6.9 Hz), 1.11 (t,
2J HH ) 14.1 Hz, J HH ) 2 Hz), 3.35 (t, 1H, CH2, J HH ) 3J HH
)
3H, Me, J HH ) 6.9 Hz), 1.37 (t, 3H, Me, J HH ) 7.2 Hz), 1.57
3
2
3
3
13.5 Hz), 3.55 (m, 1H, NH), 4.45 (d, 1H, CH2, 2J HH ) 13.5 Hz),
6.70-7.70 (m, 29H, C6H4 and Ph).
(t, 3H, Me, J HH ) 6.9 Hz), 1.81 (m, 2H, CH2), 2.08 (m, 2H,
CH2), 2.26 (s, 5H, MeC6H3 and CH2), 2.68 (s, 6H, MeC6H3, Et,
and 1H of CH2), 3.21 (m, 1H, NH), 3.46 (d, 1H, CH2, J HH
3
2
Syn th esis of [P d {C(dNtBu )C(R)dC(R)C(R)dC(R)C6H4-
(CH2NHCH2P h )-2}Br ] [R ) Me (10a )]. To a solution of
complex 6a (154 mg, 0.314 mmol) in CH2Cl2 (15 mL) was added
tBuNC (36 µL, 0.319 mmol). After 12 h, a yellow solution was
formed, which was filtered through a plug of MgSO4. The
solvent was removed to ca. 2 mL, and diethyl ether (25 mL)
was added to precipitate complex 10a as a yellow solid, which
was collected, washed with diethyl ether, and air-dried.
Yield: 120 mg, 0.209 mmol, 67%. Mp: 165-166 °C. ΛM ) 2
)
2
12.3 Hz), 3.85 (d, 1H, CH2, J HH ) 13.2 Hz), 4.13 (d, 1H, CH2,
2J HH ) 12.3 Hz), 7.08-7.47 (m, 12H, C6H3, C6H4 and Ph).
Syn t h esis of [P d {C(dO)C(R )dC(R )C(R )dC(R )C6H 4-
(CH2NHCH2P h )-2}(p y)]OTf [R ) Me (12)]. To a solution of
complex 9a (315 mg, 0.607 mmol) in CH2Cl2 (15 mL) was added
Tl(OTf) (215 mg, 0.607 mmol), and the mixture was stirred
for 5 h and then filtered through Celite. The solvent was
removed to ca. 1 mL, and a mixture of diethyl ether/n-hexane
(25 mL, 1:1) was added to precipitate a pale yellow solid, which
was taken up in CH2Cl2 (15 mL). Pyridine (0.2 mL, 2.0 mmol)
was added, and the resulting pale yellow solution was stirred
for 22 h and filtered through MgSO4. The solvent was removed
to ca. 1 mL, and diethyl ether was added to precipitate complex
12 as a pale yellow solid, which was collected and air-dried.
Yield: 236 mg, 0.354 mmol, 58%. Mp: 202 °C. ΛM ) 91 Ω-1
cm2 mol-1 (4.5 × 10-4 mol L-1). Anal. Calcd for C29H31F3N2O4-
PdS (667.1): C, 52.21; H, 4.68; N, 4.20; S, 4.80. Found: C,
52.08; H, 4.83; N, 3.50; S, 5.09. IR (Nujol, cm-1): ν(NH) ) 3230,
ν(CO) ) 1698. 1H NMR (CDCl3): δ ) 1.70 (s, 3H, Me), 1.71 (s,
3H, Me), 2.20 (s, 3H, Me), 2.29 (s, 3H, Me), 2.99 (dd, 1H, CH2,
Ω-1 cm2 mol-1 (5.57 × 10-4 mol L-1). Anal. Calcd for C27H35
-
BrN2Pd (573.9): C, 56.51; H, 6.14; N, 4.88. Found: C, 56.56;
H, 6.18; N, 4.78. IR (Nujol, cm-1): ν(NH) ) 3245, ν(CN) ) 1662,
1
1633. H NMR (CDCl3): δ ) 1.69 (s, 3H, Me), 1.73 (s, 9H, Me
t
of Bu), 1.84 (s, 3H, Me), 1.97 (s, 3H, Me), 2.00 (s, 3H, Me),
2
2.73 (m, 1H, CH2), 2.98 (m, 1H, CH2), 3.60 (d, 1H, CH2, J HH
2
) 12.5 Hz), 4.03 (m, 1H, NH), 4.27 (dd, 1H, CH2, J HH ) 12.5
Hz, 3J HH ) 3 Hz), 7.08 (m, 1H, C6H4), 7.16 (m, 1H, C6H4), 7.23-
7.46 (m, 7H, C6H4 and Ph).
Syn th esis of [P d {C(dNtBu )C(R)dC(R)C(R)dC(R)C6H4-
(CH2NHCH2P h )-2}Br ] [R ) Et (10b)]. To a solution of
complex 6b (120 mg, 0.216 mmol) in CH2Cl2 (15 mL) was added
tBuNC (25 µL, 0.216 mmol). After 12 h, a yellow solution was
formed, which was filtered through a plug of MgSO4. The
solvent was removed to ca. 2 mL, and diethyl ether (25 mL)
was added to precipitate complex 10b as a yellow solid, which
was collected, washed with diethyl ether, and air-dried.
Yield: 110 mg, 0.175 mmol, 81%. Mp: 166-168 °C. ΛM ) 0
3
2J HH ) 13.2 Hz, J HH ) 9.9 Hz), 3.49 (m, 1H, CH2), 3.71
(apparent d, 1H, CH2), 3.97 (m, 1H, NH), 4.52 (apparent d,
1H, CH2), 7.07-7.50 (m, 12H, C6H4 and Ph and py), 7.73 (m,
1 H, py), 8.46 (d, 1H, py).
Syn t h esis of [P d {C(dO)C(R )dC(R )C(R )dC(R )C6H 4-
(CH2NHCH2P h )-2}(CNtBu )]OTf [R ) Me (13)]. To a solu-
tion of complex 9a (110 mg, 0.212 mmol) in CH2Cl2 (15 mL),
was added Tl(OTf) (75 mg, 0.21 mmol), and the mixture was
Ω-1 cm2 mol-1 (5.0 × 10-4 mol L-1). Anal. Calcd for C31H43
-
BrN2Pd (630.0): C, 59.10; H, 6.87; N, 4.45. Found: C, 59.04;
H, 6.95; N, 4.38. IR (Nujol, cm-1): ν(NH) ) 3240, ν(CN) ) 1652,
stirred for 1 h and then filtered through Celite. BuNC (25
t
1
3
1626. H NMR (CDCl3): δ ) 0.90 (t, 3H, Me, J HH ) 7.5 Hz),
µL, 0.22 mmol) was added, and the resulting solution was
stirred for 23 h and filtered through Celite. The solvent was
removed to ca. 1 mL, and n-hexane (25 mL) was added to
precipitate complex 13 as a pale yellow solid, which was
collected and air-dried. Yield: 115 mg, 0.171 mmol, 81%. Mp:
135 °C. ΛM ) 145 Ω-1 cm2 mol-1 (4.8 × 10-4 mol L-1). Anal.
Calcd for C29H35F3N2O4PdS (671.1): C, 51.90; H, 5.26; N, 4.17;
S, 4.78. Found: C, 51.93; H, 5.40; N, 4.20; S, 4.73. IR (Nujol,
3
3
1.04 (t, 3H, Me, J HH ) 7.5 Hz), 1.20 (t, 3H, Me, J HH ) 7.5
Hz), 1.51 (m, 3H, Me), 1.76 (s, 9H, Me of Bu), 1.88 (m, 2H,
t
Et), 2.19 (m, 4H, Et), 2.36 (m, 4H, Et), 2.65 (m, 2H of Et and
2
1H of CH2), 3.02 (m, 1H, CH2), 3.55 (d, 1H, CH2, J HH ) 13.0
Hz), 4.02 (m, 1H, NH), 4.26 (dd, 1H, CH2, 2J HH ) 13.0 Hz, 3J HH
) 3.3 Hz), 7.14-7.42 (m, 9H, C6H4 and Ph).
Syn th esis of [P d {C(dNC6H3Me2-2,6)C(R)dC(R)C(R)d
C(R)C6H4(CH2NHCH2P h )-2}Br ] [R ) Me (11a )]. To a
solution of complex 6a (155 mg, 0.316 mmol) in CH2Cl2 (15
mL) was added 2,6-Me2C6H3NC (41 mg, 0.316 mmol). After
11 h, a dark yellow solution was formed, which was filtered
through a plug of MgSO4. The solvent was removed to ca. 2
mL, and n-hexane (25 mL) was added to precipitate complex
11a as a yellow solid, which was collected, washed with
n-hexane, and air-dried. Yield: 157 mg, 0.257 mmol, 81%. Mp:
188-190 °C. ΛM ) 0 Ω-1 cm2 mol-1 (5.14 × 10-4 mol L-1). Anal.
Calcd for C31H35BrN2Pd (621.9): C, 59.86; H, 5.67; N, 4.50.
Found: C, 59.55; H, 5.70; N, 4.43. IR (Nujol, cm-1): ν(NH) )
1
cm-1): ν(NH) ) 3196, ν(CN) ) 2195, ν(CO) ) 1688. H NMR
(CDCl3): δ ) 1.39 (s, 9H, CMe), 1,73 (s, 3H, Me), 1.79 (s, 3H,
Me), 2.18 (s, 3H, Me), 2.32 (s, 3H, Me), 2.95 (apparent t, 1H,
2
3
CH2), 3.38 (dd, 1H, CH2, J HH ) 12.0 Hz, J HH ) 4.8 Hz), 4.03
(apparent d, 1H, CH2), 4.53 (apparent d, 1H, CH2), 5.33 (m,
1H, NH), 7.06-7.49 (m, 9H, C6H4 and Ph).
Syn t h esis of [P d {C(dO)C(R )dC(R )C(R )dC(R )C6H 4-
(CH2NHCH2P h )-2}(p h en )]OTf [R ) Me (14)]. To a solution
of complex 9a (128 mg, 0.247 mmol) in CH2Cl2 (15 mL) was
added Tl(OTf)(87 mg, 0.65 mmol), and the mixture was stirred
for 1 h and then filtered through Celite. 1,10-Phenanthroline
(52 mg, 0.26 mmol) was added, and the resulting solution was
1
3249. H NMR (CDCl3, -60 °C): δ ) 1.74 (s, 3H, Me), 2.04 (s,

2688 Organometallics, Vol. 18, No. 14, 1999
Ta ble 1. Cr ysta l Da ta for Com p lexes 2‚CH2Cl2, 7, 9a , a n d 13
Vicente et al.
2‚CH2Cl2
7
9a
13
formula
Mr
C
29H30Br2Cl2N2Pd2
C28H31F3N2O3PdS
639.01
C23H26BrNOPd
518.76
C29H35F3N2O4PdS
671.05
850.07
source
CH2Cl2 slow
evaporation
yellow needle
monoclinic
7.9861(6)
22.350(2)
16.949(2)
90.960(7)
3024.9(4)
4
Et2O/CH2Cl2
liquid diffusion
colorless prism
monoclinic
10.595(2)
16.958(2)
15.978(2)
103.21(1)
2794.8(7)
4
Et2O/CH2Cl2
liquid diffusion
yellow tablet
orthorhombic
10.935(2)
n-hexane/CH2Cl2
liquid diffusion
colorless plate
monoclinic
9.5021(14)
27.997(4)
11.2982(14)
102.433(12)
2935.2(7)
4
cryst habit
cryst system
a (Å)
b (Å)
c (Å)
17.524(3)
22.241(4)
â (deg)
V (Å3)
4261.9(12)
8
Z
λ (Å)
T (K)
0.710 73
293(2)
0.710 73
173(2)
0.710 73
183(2)
0.710 73
173(2)
radiation used
monochromator
space group
cryst size (mm)
Mo KR
Mo KR
Mo KR
Mo KR
graphite
P21/n
graphite
P21/c
graphite
Pbca
graphite
P21/n
0.72 × 0.06 × 0.06
0.35 × 0.25 × 0.20
0.48 × 0.44 × 0.16
0.50 × 0.35 × 0.06
µ (mm-1
abs corr
transms
)
4.029
0.791
2.758
0.759
ψ scans
ψ scans
ψ scans
0.979/0.468
Siemens P4
ω scans
6-50
(h,+k,(l
14 234
3747
0.0411
ψ scans
0.857/0.678
Siemens P4
ω scans
0.802/0.774
Siemens P4
ω scans
0.847/0.748
Siemens P4
ω scans
diffractometer
scan method
2θ range (deg)
hkl limits
no. rflns measd
no. indep rflns
Rint
6-50
6-50
6-50
-h,(k,(l
-h,+k,(l
+h,-k,(l
7223
3377
5199
4918
9546
5173
0.0322
0.0348
0.0561
0.1465
0.0542
0.1174
0.0219
0.0292
0.0527
R1a
0.0220
0.0340
wR2b
R1 ) ∑||Fo| - |Fc||/∑|Fo| for reflections with I > 2σ(I). wR2 ) [∑[w(Fo - Fc2)2]/∑[w(Fo2)2]]0.5 for all reflections; w-1 ) σ2(F2) + (aP)2
a
b
2
+ bP, where P ) (2Fc + Fo2)/3 and a and b are constants set by the program.
2
stirred for 5 h and filtered through MgSO4. The solvent was
removed to ca. 1 mL, and diethyl ether (25 mL) was added to
precipitate complex 14 as a pale yellow solid, which was
collected and air-dried. Yield: 148 mg, 0.193 mmol, 78%. Mp:
174 °C. ΛM ) 81 Ω-1 cm2 mol-1 (3.6 × 10-4 mol L-1). Anal.
Calcd for C36H34F3N3O4PdS (768.2): C, 56.29; H, 4.46; N, 5.47;
S, 4.17. Found: C, 55.63; H, 4.73; N, 5.06; S, 3.43. IR (Nujol,
cm-1): ν(NH) ) 3269, 3230; ν(CO) ) 1688. 1H NMR ([D6]-
acetone): δ ) 1.43 (s, 3H, Me), 1.95 (s, 3H, Me), 2.26 (s, 3H,
Me), 2.34 (s, 3H, Me), 3.28 (m, 2H, CH2), 3.42 (m, 1H, NH),
3.67 (apparent d, 1H, CH2), 4.96 (dd, 1H, CH2, J HH ) 13.2,
Maximum ∆/σ ) 0.001, and maximum ∆F ) 1.78 e- Å-3. For
compound 7 the final R(F) [I > 2σ(I)] was 0.0292, for 351
parameters and 11 restraints. Maximum ∆/σ ) 0.001, and
maximum ∆F ) 0.35 e- Å3. For compound 9a the final R(F) [I
> 2σ(I)] was 0.0220, for 248 parameters and 225 restraints.
Maximum ∆/σ ) 0.001, and maximum ∆F ) 0.34 e- Å-3. For
compound 13 the final R(F) [I > 2σ(I)] was 0.0348, for 372
parameters and 11 restraints. Maximum ∆/σ ) 0.002, and
maximum ∆F ) 0.38 e- Å-3. Restraints were applied to local
ring symmetry and U components of neighboring light atoms.
The programs use the neutral atom scattering factors, ∆f ′ and
∆f ′′, and absorption coefficients from the International Tables
for Crystallography.88 Selected bond lengths and angles for the
compounds are found in Tables 2-5.
3
J HH ) 3.6 Hz), 6.63 (d, 1H, C6H4, J HH ) 7.5 Hz), 6.91 (t, 1H,
3
3
C6H4, J HH ) 7.5 Hz), 7.07 (t, 1H, C6H4, J HH ) 7.5 Hz), 7.34-
3
7.58 (m, 6H, C6H4 and C6H5), 7.73 (dd, 1H, H3, phen, J HH
)
4.8 Hz, 3J HH ) 8.1 Hz), 8.14 (dd, 1H, H3, phen, 3J HH ) 4.5 Hz,
3J HH ) 7.8 Hz), 8.25 (d, 1H, H5, phen, 3J HH ) 9.0 Hz), 8.31 (d,
Resu lts
3
3
1H, H5, phen, J HH ) 9.0 Hz), 8.73 (d, 1H, H4, phen, J HH
)
8.1 Hz), 8.81 (s, b, 1H, H2), 8.88 (dd, 1H, H4, phen, 3J HH ) 8.1
By the refluxing in acetone of a mixture of dibenzyl-
amine and [Pd(OAc)2]3 (3.2:1 molar ratio), the complex
[Pd{C6H4(CH2NHCH2Ph)-2}(µ-OAc)]2 (1) precipitated as
a deep yellow solid which was isolated in high yield
(90%) (Scheme 1). The bromo complex [Pd{C6H4(CH2-
NHCH2Ph)-2}(µ-Br)]2 (2), obtained by reacting 1 with
NaBr, reacts with neutral ligands L to give complexes
[Pd{C6H4(CH2NHCH2Ph)-2}Br(L)] [L ) PPh3, (3a ),
NH(CH2Ph)2 (3b)], with Tl(acac) to give [Pd{C6H4(CH2-
NHCH2Ph)-2}(acac)] (4), and with AgClO4 and pyridine
(py) or 1,5-cyclooctadiene (COD) to give cationic com-
plexes [Pd{C6H4(CH2NHCH2Ph)-2}L2] [L ) py, (5a ), L2
) COD (5b)].
3
Hz), 9.82 (d, 1H, H2, phen, J HH ) 3.6 Hz).
X-r a y Str u ctu r e Deter m in a tion s. Crystals of 2‚CH2Cl2,
7, 9a , and 13 were mounted on glass fibers and transferred
to the diffractometer (Siemens P4) as summarized in Table 1.
Cell constants were refined from ca. 60 reflections in the 2θ
range 10-25°. The structure of 9a was solved by direct
methods, and the others were solved by the heavy-atom
method; all structures were subjected to anisotropic full-matrix
least-squares refinement. Programs used were SHELXL-97 (7
and 13)86 and SHELXL-93 (2‚CH2Cl2 and 9a ).87 Hydrogen
atoms bonded to nitrogen were refined freely; others were
included using rigid methyl groups or a riding model. For
compound 2‚CH2Cl2 the dichloromethane molecule is disor-
dered over two sites (68 and 32% occupancy) and the maximum
difference peak is at ca. 1 Å of the Pd(1) atom. The final R(F)
[I > 2σ(I)] was 0.0542, for 327 parameters and 301 restraints.
We attempted a double orthometalation of dibenzyl-
amine using different reaction conditions. Thus, by the
(86) Sheldrick, G. M. SHELXL 97; University of Go¨ttingen: Go¨t-
tingen, Germany, 1997.
(87) Sheldrick, G. M. SHELXL 93; University of Go¨ttingen: Go¨t-
tingen, Germany, 1993.
(88) International Tables for Crystallography; Wilson, A. J . C., Ed.;
Kluwer Academic Publishers: Dordrecht, The Netherlands, 1992; Vol.
C, Tables 6.1.1.4 (pp 500-502), 4.2.6.8 (pp 219-222), and 4.2.4.2 (pp
193-199).

Palladium-Assisted Formation of Carbon-Carbon Bonds
Organometallics, Vol. 18, No. 14, 1999 2689
a
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles (d eg) for Com p lex 2‚CH2Cl2
Pd(1)-C(1)
1.962(14)
2.430(2)
1.983(13)
2.436(2)
Pd(1)-N(1)
2.092(9)
2.580(2)
2.069(11)
2.585(2)
Pd(1)-Br(1)
Pd(1)-Br(1)#1
Pd(1A)-N(1A)
Pd(1A)-Br(1A)
Pd(1A)-C(1A)
Pd(1A)-Br(1A)#2
C(1)-Pd(1)-N(1)
83.4(5)
96.3(3)
82.8(5)
96.4(3)
C(1)-Pd(1)-Br(1)
94.8(4)
85.59(7)
95.2(4)
85.71(7)
N(1)-Pd(1)-Br(1)#1
C(1A)-Pd(1A)-N(1A)
N(1A)-Pd(1A)-Br(1A)
Br(1)-Pd(1)-Br(1)#1
C(1A)-Pd(1A)-Br(1A)#2
Br(1A)#2-Pd(1A)-Br(1A)
a
Symmetry transformations: #1, -x, -y, -z + 2; #2, -x - 1, -y, -z + 2.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Com p lex 7
Sch em e 1
Pd-C(40)
Pd-C(38)
Pd-C(37)
2.007(3)
2.226(3)
2.229(3)
Pd-N(11)
Pd-N(1)
2.088(2)
2.189(2)
C(40)-Pd-N(11)
C(40)-Pd-N(1)
N(11)-Pd-N(1)
C(40)-Pd-C(38)
C(40)-Pd-C(37)
91.40(11) N(11)-Pd-C(37)
175.88(11) N(1)-Pd-C(37)
170.31(10)
89.83(10)
36.22(10)
92.65(9)
C(38)-Pd-C(37)
64.48(11) C(10)-N(1)-C(30) 110.1(2)
86.05(11) N(1)-C(30)-C(31) 112.8(2)
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Com p lex 9a
Pd-C(1)
Pd-C(4)
Pd-C(5)
1.980(2)
2.168(2)
2.204(2)
Pd-N
Pd-Br
2.201(2)
2.5197(4)
O-C(1)
1.207(3)
1.472(4)
1.333(3)
1.500(3)
1.412(3)
C(1)-Pd-C(4)
C(1)-Pd-C(5)
C(4)-Pd-C(5)
N-Pd-C(5)
80.45(10)
94.20(10)
37.69(9)
90.77(8)
90.85(7)
C(1)-C(2)
C(2)-C(3)
C(3)-C(4)
C(4)-C(5)
C(1)-Pd-Br
Ta ble 5. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Com p lex 13
Pd-C(13)
Pd-C(14)
Pd-C(10)
Pd-C(9)
2.020(3)
2.038(4)
2.202(3)
2.228(3)
2.233(3)
1.474(5)
O(1)-C(13)
C(9)-C(10)
N(1)-C(8)
N(1)-C(7)
N(2)-C(14)
1.201(4)
1.398(5)
1.486(5)
1.491(4)
1.143(4)
Pd-N(1)
N(2)-C(15)
C(13)-Pd-C(14) 88.29(14) C(9)-Pd-N(1)
89.55(12)
C(13)-Pd-C(10) 79.47(13) C(14)-N(2)-C(15) 173.1(4)
C(13)-Pd-C(9)
C(10)-Pd-C(9)
C(14)-Pd-N(1)
97.86(13) O(1)-C(13)-C(12) 123.6(3)
36.78(12) O(1)-C(13)-Pd
86.71(13) C(12)-C(13)-Pd
118.8(3)
117.4(2)
Ph)-2}Br] [E ) O, R ) Me (9a ), Et (9b); E ) NR′, R′ )
tBu, R ) Me (10a ), Et (10b); R′ ) C6H3Me2-2,6, R ) Me
(11a ), Et (11b)] in good yields. When an excess of
isocyanide is used, oily residues are obtained that
cannot be isolated as solids. Complex 6c reacted with
heating of complex 1 in acetonitrile or chlorobenzene,
no reaction took place. By reaction of complex 1 with
AgClO4 in acetone, a substitution of the acetato ligand
by acetone occurred, as shown by 1H NMR spectroscopy.
Reaction of 4 with PPh3 or pyridine gave mixtures of
[Pd{C6H4(CH2NHCH2Ph)-2}(C-acac)(L)] (L ) PPh3, py)
and other products (by NMR spectroscopy). We also
attempted to palladate two molecules of dibenzylamine
by refluxing 3b in acetonitrile for 5 h. However, it was
recovered unchanged.
A suspension of 2 in dichloromethane reacts with an
excess of alkyne RCtCR (1:6-8 molar ratio) to give a
solution from which complex [Pd{C(R)dC(R)C(R)dC(R)-
C6H4(CH2NHCH2Ph)-2}Br] [R ) Me (6a ), Et (6b), Ph
(6c)], resulting from a double insertion of the alkyne
into the Pd-C bond, is obtained (Scheme 2). Complex
6a reacts with Tl(OTf) (OTf ) CF3SO3) and neutral
ligands L to give [Pd{C(R)dC(R)C(R)dC(R)C6H4(CH2-
NHCH2Ph)-2}L]OTf [R ) Me, L ) py (7), phen (8)]
(Scheme 2). Complexes 6a ,b insert CO or isocyanides
R′NC into the C-Pd bond to give 10-membered palla-
dacycles [Pd{C(E)C(R)dC(R)C(R)dC(R)C6H4(CH2NHCH2-
t
CO to give complex 9c, but reaction with BuNC leads
to a mixture of coordinated and inserted derivatives as
shown by two bands in the IR spectrum, at 2192 and
1650 cm-1. When the mixture was heated in chloroform,
it was recovered unchanged.
Complex 9a reacts with Tl(OTf) and neutral ligands
L to give [Pd{C(dO)C(R)dC(R)C(R)dC(R)C6H4(CH2-
t
NHCH2Ph)-2}L]OTf [R ) Me, L ) py (12), BuNC (13),
phen (14)] (Scheme 3).
We have carried out a great number of different
reactions in order to obtain organic derivatives. Thus,
we attempted to eliminate the palladium atom by
reduction of complexes 6a and 9a with PPh3 or py, but
although decomposition took place, no organic products
were isolated. When these complexes were reacted with
Zn, NaBH4, or LiAlH4, the starting materials were
recovered. We tried to break the C-Pd bond of complex
6a by using HX (X ) Cl, Br) or oxidizing agents (Cl2-
IPh, H2O2), and again, in all cases reactions take place

2690 Organometallics, Vol. 18, No. 14, 1999
Vicente et al.
42
89
Sch em e 2
h
or in acetone 8 h
and the yield was poor (40-
44%). The difficulty (but not impossibility) of cyclo-
metalating primary amines has been discussed
widely.34,37,38,40-42
To have a more soluble starting material, we ex-
changed the acetato ligand for bromo by reacting
complex 1 with NaBr to give complex 2. From 2 we have
prepared neutral and cationic complexes 3-5 resulting
from the cleavage of the bromo bridge [using PPh3 (3a )
or NH(CH2Ph)2 (3b)] or by substitution of the bromo
ligand by anionic [acetylacetonato (4)] or neutral [py (5a )
or COD (5a )] ligands (see Scheme 1).
Attempts at double orthometalation of dibenzylamine
by heating solutions of 1, in acetonitrile or chloroben-
zene, or by reacting 1 with AgClO4 proved unsuccessful,
although both methods have been applied for the
palladation of primary amines.38,40,42 A third potential
route to double orthometalation, by reacting the acac
complex 4 with PPh3 or pyridine, also failed. We
expected that the C-acac ligand in the resulting complex
[Pd{C6H4(CH2NHCH2Ph)-2}(C-acac)(L)] (L ) PPh3, py)
(detected by NMR) could deprotonate the nonpalladated
phenyl group. Benzylamine have been cyclopalladated
using [Pd(acac)2].37
The reaction of 2 with excess of alkynes takes place
by insertion of two molecules of the alkyne into the
Pd-C bond to give complexes [Pd{C(R)dC(R)C(R)d
C(R)C6H4(CH2NHCH2Ph)-2}Br] [R ) Me (6a ), Et (6b),
Ph (6c)] (see Scheme 2). This behavior is the same
as that observed in reactions of different alkynes
with
cyclopalladated
primary58
and
tertiary
amines.3,47-49,51,55,57,73,90 The only precedent for this
insertion reaction with a cyclopalladated secondary
amine is that reported by Heck between diphenyl-
acetylene and orthopalladated N-methyl-3,4-dimeth-
oxybenzylamine bromo dimer.57 Although the
insertion of one molecule of an alkyne into a [Pd]-
aryl bond always leads to a cis-arylvinylpalladium
complex,3,5,51,53,55,60,66,67,71,73,91-93 the product resulting
from a second insertion into the Pd-C bond usually
displays a [Pd]-cis-C(R)dC(R)-trans-C(R)dC(R)-aryl ge-
ometry, which requires the isomerization of the first
inserted alkyne. However, we have isolated and struc-
turally characterized a diinserted product of this type
with cis-cis geometry.93 According to the crystal struc-
ture of some derivatives of 6a (see below) we have
proposed the usual [Pd]-cis-C(R)dC(R)-trans-C(R)dC(R)-
aryl geometry, which is also in agreement with the
proposal that this is the preferred arrangement when
the starting compound is a cyclopalladated complex.93
Complex 6a reacts with Tl(OTf) and neutral ligands
to give cationic complexes [Pd{C(R)dC(R)C(R)dC(R)-
C6H4(CH2NHCH2Ph)-2}L]OTf [R ) Me, L ) py (7), phen
(8)].
Sch em e 3
but complicated mixtures were obtained from which no
pure compounds could be isolated. Similar reactions
with complex 9a led to similar disappointing results.
Whereas complexes 6a ,b insert CO or isocyanides into
the C-Pd bond to give the corresponding 10-membered
palladacycles 9-11 in good yields (Scheme 2), 6c inserts
(89) Vicente, J . Unpublished results.
(90) Maassarani, F.; Pfeffer, M.; Borgne, G. L. Organometallics 1990,
9, 3003.
Discu ssion
The cyclopalladation of dibenzylamine using [Pd-
(OAc)2]3 was very easily achieved by refluxing a mixture
(3.2:1 molar ratio) of both reagents in acetone for 2 h
giving a high yield (90%) of the complex 1, whereas that
of benzylamine required refluxing in acetonitrile for 4
(91) Ossor, H.; Pfeffer, M.; J astrzebski, J . T. B. H.; Stam, C. H. Inorg.
Chem. 1987, 26, 1169.
(92) Dupont, J .; Pfeffer, M.; Daran, J .-C.; Gouteron, J . J . Chem. Soc.,
Dalton Trans. 1988, 2421.
(93) Vicente, J .; Abad, J . A.; Ferna´ndez-de-Bobadilla, R.; J ones, P.
G.; Ram´ırez de Arellano, M. C. Organometallics 1996, 15, 24.

Palladium-Assisted Formation of Carbon-Carbon Bonds
Organometallics, Vol. 18, No. 14, 1999 2691
Sch em e 4
CO to give the corresponding complex 9c, but its
t
reaction with BuNC lead to a mixture of coordinated
and inserted derivatives. Insertion of CO6,94-111 and
isocyanides1,6,108-118 into the C-Pd bond of alkyl-,
π-allyl-, and arylpalladium complexes are very well
studied reactions, but those leading to complexes 9-11
have, as their only precedent, a CO insertion reported
in the above-mentioned work by Heck.57 However, in
this case, the CO insertion took place at 50 °C and 25
psi. Recently, the reaction of 4-octyne with ArI (Ar )
Ph, p-tolyl) and CO (10-40 atm) in the presence of Et3N
and catalytic amounts of [PdCl2(PPh3)2] at 100-140 °C
to give 2-butenolides has been reported.82 A sequential
insertion of carbon monoxide-alkyne-carbon monoxide
was postulated (Scheme 4). We have attempted to
F igu r e 1. Ellipsoid representation (50% probability),
showing the labeling scheme of one of the centrosymmetric
dimers of complex 2‚CH2Cl2.
prepare PhCH2C6H4C(Me)dC(Me)C(Me)dC(Me)CO2-
Me-2 by reacting 9a with Et3N in MeOH following a
similar reported reaction of cyclopalladated complexes
with CO and Et3N.7 However, although reaction takes
place (as shown by extensive decomposition to Pd metal)
even after removal of the metal, Et3NHBr, and some
starting material, we could not separate the mixture of
organic products.
Complex 9a reacts with Tl(OTf) and neutral ligands
to give cationic complexes [Pd{C(dO)C(R)dC(R)C(R)d
C(R)C6H4(CH2NHCH2Ph)-2}L]OTf [R ) Me, L ) py
(94) Vicente, J .; Abad, J . A.; Frankland, A. D.; Ram´ırez de Arellano,
M. C. Chem. Commun. 1997, 959.
t
(12), BuNC (13), phen (14)] (Scheme 3). Complexes 7
(95) Garrou, P. E.; Heck, R. F. J . Am. Chem. Soc. 1976, 98, 4115.
(96) Yamamoto, A. J . Organomet. Chem. 1995, 500, 337.
(97) Yamamoto, Y. Bull. Chem. Soc. J pn. 1995, 68, 433.
(98) Delis, J . G. P.; Rep, M.; Ru¨lke, R. E.; van Leeuwen, P.; Vrieze,
K.; Fraanje, J .; Goubitz, K. Inorg. Chim. Acta 1996, 250, 87.
(99) Green, M. J .; Britovsek, G. J . P.; Cavell, K. J .; Skelton, B. W.;
White, A. H. Chem. Commun. 1996, 1563.
(100) Ankersmit, H. A.; Loken, B. H.; Kooijman, H.; Spek, A. L.;
Vrieze, K.; van Koten, G. Inorg. Chim. Acta 1996, 252, 141.
(101) Dekker, G.; Buijs, A.; Elsevier, C. J .; Vrieze, K.; Vanleeuwen,
P.; Smeets, W. J . J .; Spek, A. L.; Wang, Y. F.; Stam, C. H. Organo-
metallics 1992, 11, 1937.
(102) J in, H.; Cavell, K. J .; Skelton, B. W.; White, A. H. J . Chem.
Soc., Dalton Trans. 1995, 2159.
(103) Reger, D. L.; Garza, D. G. Organometallics 1993, 12, 554.
(104) Markies, B. A.; Kruis, D.; Rietveld, M. H. P.; Verkerk, K. A.
N.; Boersma, J .; Kooijman, H.; Lakin, M. T.; Spek, A. L.; van Koten,
G. J . Am. Chem. Soc. 1995, 117, 5263.
and 12 contain only one molecule of pyridine even when
an excess of this ligand is used.
Str u ctu r e of Com p lexes. The insolubility of com-
plex 1 in organic solvents prevents the recording of its
NMR spectra. However, it has been formulated as a
dimer by analogy to all reported complexes of this
type,119-121 including complex 2 whose crystal structure
has been solved (see below). Both N atoms in complex
2 are chiral centers, and cis/ trans isomerism at the two
palladium atoms led up to six possible stereoisomers.
The solid-state crystal structure of 2 is that of the trans-
RS isomer (Figure 1), and NMR data in acetone-d6 is
in accordance with this structure. More likely, however,
due to the similar behavior in acetone solution of 2 and
RS-[Pd(C6H4CHMeNH2-2)(µ-Br)2],40 the NMR data of 2
could be those of [Pd{C6H4(CH2NHCH2Ph)-2}(Br)(ac-
etone-d6)].
(105) Wehman, P.; Rulke, R. E.; Kaasjager, V. E.; Kamer, P. C. J .;
Kooijman, H.; Spek, A. L.; Elsevier, C. J .; Vrieze, K.; Vanleeuwen, P.
J . Chem. Soc., Chem. Commun. 1995, 331.
(106) Toth, I.; Elsevier, C. J . J . Am. Chem. Soc. 1993, 115, 10388.
(107) Ozawa, F.; Hayashi, T.; Koide, H.; Yamamoto, A. J . Chem.
Soc., Chem. Commun. 1991, 1469.
The crystal structure of 2‚CH2Cl2 is the first of a
cyclopalladated secondary amine and also the first
bromo-bridged cyclopalladated amine. The few reported
bromo-bridged cyclopalladated complexes are derived
from imines or azobenzene.122-126 For complex 2‚CH2-
Cl2 there are two independent centrosymmetric pal-
(108) Kim, Y. J .; Song, S. W.; Lee, S. C.; Lee, S. W.; Osakada, K.;
Yamamoto, T. J . Chem. Soc., Dalton Trans. 1998, 1775.
(109) Campora, J .; Graiff, C.; Palma, P.; Carmona, E.; Tiripicchio,
A. Inorg. Chim. Acta 1998, 269, 191.
(110) Kayaki, Y.; Shimizu, I.; Yamamoto, A. Bull. Chem. Soc. J pn.
1997, 70, 917.
(111) Gutierrez, E.; Nicasio, M. C.; Paneque, M.; Ruiz, C.; Salazar,
V. J . Organomet. Chem. 1997, 549, 167.
(112) Delis, J . G. P.; Aubel, P. G.; Vrieze, K.; Vanleeuwen, P.;
Veldman, N.; Spek, A. L.; Vanneer, F. J . R. Organometallics 1997, 16,
2948.
(113) Yamamoto, Y. Coord. Chem. Rev. 1980, 32, 193.
(114) Singleton, E.; Oosthuizen, H. E. Adv. Organomet. Chem. 1983,
22, 209.
(119) Omae, I. Organometallic Intramolecular-Coordination Com-
pounds; Elsevier: Amsterdam, The Netherlands, 1986.
(120) Dunina, V. V.; Zalevskaya, O. A.; Potapov, V. M. Russ. Chem.
Rev. 1988, 57, 250.
(121) Ryabov, A. D. Chem. Rev. 1990, 90, 403.
(115) Veya, P.; Floriani, C.; Chiesivilla, A.; Rizzoli, C. Organome-
tallics 1993, 12, 4899.
(116) Onitsuka, K.; Ogawa, H.; J oh, T.; Takahashi, S.; Yamamoto,
Y.; Yamazaki, H. J . Chem. Soc., Dalton Trans. 1991, 1531.
(117) Onitsuka, K.; Yanai, K.; Takei, F.; J oh, T.; Takahashi, S.
Organometallics 1994, 13, 3862.
(122) Barro, J .; Granell, J .; Sainz, D.; Sales, J .; Fontbardia, M.;
Solans, X. J . Organomet. Chem. 1993, 456, 147.
(123) Vila, J . M.; Gayoso, M.; Pereira, M. T.; Ortigueira, J . M.;
Ferna´ndez, A.; Bailey, N. A.; Adams, H. Polyhedron 1993, 12, 171.
(124) Crispini, A.; Ghedini, M.; Neve, F. J . Organomet. Chem. 1993,
448, 241.
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K. J . Organomet. Chem. 1993, 456, 287.
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J . J .; Thornton-Pett, M. J . Organomet. Chem. 1991, 401, 385.

2692 Organometallics, Vol. 18, No. 14, 1999
Vicente et al.
ladium dimers with coplanar coordination planes. With
few exceptions, this disposition is normal in dimeric
halo-bridging cyclometalated complexes of d8 ele-
ments.127 The Pd-Br bond distances in 2 [2.430(2)-
2.436(2) Å (trans to N), 2.580-2.585(2) (trans to C) Å]
are consistent with the greater trans influence of the
aryl group than the amine. Similar values for these bond
lengths and also for the C-Pd [1.962(14), 1.983(13) Å]
and the N-Pd [2.069(11), 2.092(9) Å] bond distances
have been found in bromo-bridged cyclopalladated imines
and azobenzene [Pd-Br, 2.639(1)-2.548(4) Å (trans to
C), 2.450(1)-2.439(3) Å (trans to N); C-Pd, 1.954(24)-
2.021(7); N-Pd, 2.022(18)-2.050(5)].
The structure proposed for complex 3a takes into
account the inherent instability of Pd(II) complexes
containing one C and one P donor ligands in mutually
trans positions128 (transphobia).94,129 The proposed ge-
ometry of the dibenzylamine adduct 3b is based on
that of the related complex [Pd{C6H4{CH(Me)NH2}-
2}Br{NH2CH(Me)Ph}].130 The proposed structures for
complexes 6, 9b,c, and 10-12 are based on the crystal
structure of 7, 9a , and 13 and those of related
complexes.47-49,51,52,57,92,131,132 The structures proposed
for 8 and 14 are based on the assumption that they are
square-planar complexes. However, a pentacoordination
involving an additional π-bond between the trans-vinyl
group and the palladium atom cannot be discarded.
F igu r e 2. Ellipsoid representation (50% probability),
showing the labeling scheme of complex 7 and the triflate
anion and the cation interaction. H atoms (except N-H)
are omitted for clarity.
The IR spectra of all complexes show a ν(NH) band
in the range 3166-3280 cm-1. Those resulting after CO
insertion show a ν(CO) band in the range of 1675-1700
cm-1. Those complexes resulting after isocyanide inser-
tion show one or two bands in the range of 1626-1662
cm-1, one of which should be assigned to ν(CN). Simi-
larly, complexes 11a ,b show three bands in the range
of 1660-1580 cm-1, one of which should also be assigned
to ν(CN). In complex 13, ν(CN) appears at 2195 cm-1
as expected for a coordinated isonitrile.
F igu r e 3. Ellipsoid representation (50% probability),
showing the labeling scheme of complex 9a .
The structure of complex 7 (Figure 2) is similar to that
of related complexes resulting from the insertion of
alkynes into cyclopalladated complexes; i.e., it shows the
first alkyne molecule inserted as a trans-vinyl group
π-bonded to palladium, while the second one is cis, with
the last carbon atom σ-bonded to palladium and coor-
dinated trans to the amine N atom. However, 7 is the
only cationic complex of this family of X-ray structurally
characterized complexes; all the others are neutral
complexes of the type [Pd{C(R1)dC(R2)C(R3)dC(R4)-
Ar}X] [Ar ) (Cp)FeC5H3CH2NMe2-2, X ) Cl, R1 ) R2 )
R3 ) R4 ) Ph,47 Et;48,57 Ar ) C6H4CH2NdCH(C6H3Cl2-
2,6)-2, X ) Br, R1 ) R2 ) R3 ) R4 ) Ph;131 X ) Cl, R1
) R2 ) R3 ) R4 ) Ph, Ar ) (Cp)FeC5H3CHdNR5-2, R5
132
) CH2Ph,52 CHMeC6H11, CH2C9H15
;
Ar ) C6H4CH2-
NMe2, X ) Br, R1 ) R3 ) Me, R2 ) R4 ) Ph, R1 ) R4 )
(126) Vila, J . M.; Gayoso, M.; Pereira, M. T.; Rodriguez, M. C.;
Ortigueira, J . M.; Thornton-Pett, M. J . Organomet. Chem. 1992, 426,
267.
F igu r e 4. Ellipsoid representation (50% probability),
showing the labeling scheme of the cation of complex 13.
(127) Aullon, G.; Ujaque, G.; Lledos, A.; Alvarez, S.; Alemany, P.
Inorg. Chem. 1998, 37, 804.
(128) Pearson, R. G. Inorg. Chem. 1973, 12, 712.
(129) Vicente, J .; Arcas, A.; Bautista, D.; J ones, P. G. Organome-
tallics 1997, 16, 2127.
(130) Albert, J .; Granell, J .; Luque, A.; Minguez, J .; Moragas, R.;
Fontbardia, M.; Solans, X. J . Organomet. Chem. 1996, 522, 87.
(131) Albert, J .; Granell, J .; Sales, J .; Solans, X. J . Organomet.
Chem. 1989, 379, 177.
(132) Zhao, G.; Wang, Q. G.; Mak, T. C. W. Tetrahedron: Asymmetry
1998, 9, 2253.
Me, R2 ) R3 ) Ph;49 Ar ) C6H4CH2NMe2, X ) Cl, R1 )
Ph, R2 ) Me, R3 ) R4 ) CO2Me;51 Ar ) C6H4NdC(Me)-
NHPh, X ) Cl, R1 ) R3 ) Ph, R2 ) R4 ) CO2Et].92 There
is no crystal structure of any complex related to com-
plexes 9a and 13.
Because complexes 7, 9a (Figure 3), and 13 (Figure
4) present some common features, we will discuss their

Palladium-Assisted Formation of Carbon-Carbon Bonds
Organometallics, Vol. 18, No. 14, 1999 2693
structures together. The Pd, the three atoms directly
σ-coordinated to it, and the midpoint of the π-bonded
CdC group display a very distorted square-planar
coordination: the angles between the planes L-Pd-N
[L ) N(11) (7), Br (9a ), C(14) (13)] and C(n)-Pd-X (n
) 40 (7), 1 (9a ), 13 (13); X ) midpoint of CdC)] are 5.1°
(7), 24.9° (9a ), and 28.2° (13). The angles between the
CdC segments and the mean coordination planes are
50.8° (7), 57.6° (9a ), and 40.8° (13). The Pd-Namine bond
distances [2.189(2) (7), 2.201(2) (9a ), 2.233(3) (13) Å] are
significantly longer than the Pd-Npyridine bond distance
in 7 [2.088(2) Å] and even longer than the Pd-Namine
bond distance in complex 2 [2.041(2) Å], as attributable
to the trans influence of the ligands: σ-bonded C >
π-bonded alkene > Br. The Pd-Br bond distance in 9a
[2.5197(4) Å] is intermediate between those in complex
2 [2.430(2) (trans to N), 2.580(2) (trans to C) Å] sug-
gesting the series of trans influence: aryl > π-bonded
alkene > Namine. The Pd-C bond distances do not differ
greatly, at around 2 Å [2.007(3) (7), 1.980(2) (9a ), 2.020-
(3) (13) Å]. The CdO bond distances are normal for acyl
complexes [1.207(3) (9a ), 1.201(4) (13) Å].133 In complex
7, the triflate anion is hydrogen bonded with the NH
group [H‚‚‚O, 2.51(3) Å; N‚‚‚O, 3.178(4), Å; N-H‚‚‚O,
145(2)°] (Figure 2). Complex 9a forms dimers through
a pair of hydrogen bonds between the oxygen atom of
the carbonyl group and the NH group [H‚‚‚O, 2.08 Å;
N‚‚‚O, 2.932(3), Å; N-H‚‚‚O, 152°] (Figure 5). In com-
plex 13, the triflate anion bridges, intramolecularly, the
NH group, via a hydrogen bond [H‚‚‚O, 2.21(3) Å;
F igu r e 5. View of the dimers formed in 9a through
hydrogen bonds.
N‚‚‚O, 3.011(4) Å; N-H‚‚‚O, 169(3)°], and the palladium
atom via a weak Pd‚‚‚O contact [Pd‚‚‚O, 3.076 Å].
Ack n ow led gm en t. We thank the DGES (Grant
PB97-1047) and the Fonds der Chemischen Industrie
for financial support. M.C.R.A. thanks the Ministerio
de Educacio´n y Cultura (Spain) for a contract.
Su p p or tin g In for m a tion Ava ila ble: Tables giving crys-
tal data and structure refinement details, positional and
thermal parameters, and bond distances and angles for 2, 7,
9a , and 13 (26 pages). This material is available free of charge
via the Internet at http://pubs.acs.org.
(133) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, T. J . Chem. Soc., Dalton Trans. 1989, S1.
OM990143Y