Synthesis and reactivity of ortho-palladated phenylacetamides. Intramolecular C-N vs C-O reductive coupling after CO or XyNC insertion into the Pd-C bond. Synthesis of isoquinoline- and isocoumarin-based heterocycles

Article abstract of DOI:10.1021/om101110s

Aryl palladium complexes [Pd{C₆H₄CH ₂C(O)NRR′-2}I(N^N)] (N^N = N,N,N′,N′- tetramethylethylenediamine = tmeda, NRR′ = NH₂ (1a), NHMe (1b), NMe₂ (1c); N^N = 4,4′-di-tert-butyl-2,2′-bipyridyl (dbbpy), NR

Full text of DOI:10.1021/om101110s

Organometallics 2011, 30, 1079–1093 1079
DOI: 10.1021/om101110s
Synthesis and Reactivity of Ortho-Palladated Phenylacetamides.
Intramolecular C-N vs C-O Reductive Coupling after CO or XyNC
Insertion into the Pd-C Bond. Synthesis of Isoquinoline- and
Isocoumarin-Based Heterocycles
ꢀ
Jose Vicente,* Pablo Gonzalez-Herrero, Roberto Frutos-Pedreno, and Marıa-Teresa Chicote
ꢀ
~
´ ꢀ ´
Grupo de Quımica Organometalica, Departamento de Quımica Inorganica, Facultad de Quımica,
´
Universidad de Murcia, Apartado 4021, 30071 Murcia, Spain
ꢀ
Peter G. Jones*
Institut fu€r Anorganische und Analytische Chemie, Technische Universita€t Braunschweig, Postfach 3329,
38023 Braunschweig, Germany
Delia Bautista*
SAI, Universidad de Murcia, Apartado 4021, 30071 Murcia, Spain
Received November 26, 2010
Aryl palladium complexes [Pd{C6H4CH2C(O)NRR0-2}I(N∧N)] (N∧N = N,N,N0,N0-tetramethylethy-
lenediamine = tmeda, NRR0 = NH2 (1a), NHMe (1b), NMe2 (1c); N∧N = 4,40-di-tert-butyl-2,20-
bipyridyl (dbbpy), NRR0 = NHMe (1b0)) are prepared by oxidative addition of the corresponding 2-(2-
iodophenyl)acetamide to “Pd(dba)2” ([Pd2(dba)3] dba; dba = dibenzylideneacetone) in the presence of
3
the N∧N chelating ligand. Cationic cyclometalated derivatives [Pd{κ2C,O-C6H4CH2C(O)NRR0-2}-
(N∧N)]OTf (N∧N = tmeda, NRR0 = NH2 (2a), NHMe (2b), NMe2 (2c); N∧N = dbbpy, R = NHMe
(2b0)) are obtained by reacting the appropriate complex 1 with AgOTf. The reaction of 2b0 with PPh3
affords [Pd{C6H4CH2C(O)NHMe-2}(dbbpy)(PPh3)]OTf (3b0). Neutral amidate complexes of the type
[Pd{κ2C,N-C6H4CH2C(O)NR-2}(N∧N)] (N∧N = tmeda, R = H (4a), Me (4b); N∧N = dbbpy, R = Me
(4b0)) are obtained upon deprotonation of the corresponding complex 1 with KOtBu. The complex
[Pd{C6H4CH2C(O)NHMe-2}{CH(CN)2}(dbbpy)] (5b0) has been prepared by reacting 4b0 with malono-
nitrile. Acyl derivatives [Pd{C(O)C6H4CH2C(O)NRR0-2}I(N∧N)] (N∧N = tmeda, NRR0 = NH2 (6a),
NHMe (6b), NMe2 (6c); N∧N = dbbpy, NRR0 = NHMe (6b0)) have been prepared by reacting the
corresponding complex 1 with CO at low temperature; when N∧N = tmeda, prolonged reaction times and
high temperatures lead to Pd(0) and isoquinoline-1,3(2H,4H)-dione (7a), a 1:2 mixture of 2-methy-
lisoquinoline-1,3(2H,4H)-dione (7b) and 3-(dimethylamino)-1H-2-benzopyran-1-one (8b), or 3-(methyl-
amino)-1H-2-benzopyran-1-one (8c), respectively. Similar results are obtained from the reactions of 2a-c
with CO under much milder conditions, while 2b0 reacts with CO in acetone to give the isochroman-1-one
derivative N,3,3-trimethyl-1-oxo-3,4-dihydro-1H-2-benzopyrane-4-carboxamide (9). While the reaction of
1b0 with 1 equiv of XyNC (Xy = 2,6-dimethylphenyl) gives the iminoacyl complex [Pd{C(dNXy)-
C6H4CH2C(O)NHMe-2}I(dbbpy)] (10b0), the homologous products from the tmeda derivative 1a, 1b, or
1c decompose, giving Pd(0) and 1-(2,6-dimethylphenylimino)-1,2-dihydroisoquinolin-3(4H)-one (11a),
1-(2,6-dimethylphenylimino)-2-methyl-1,2-dihydroisoquinolin-3(4H)-one (11b), or 1-(2,6-dimethylphenyl-
imino)-3-(N,N-dimethylamino)-1H-2-benzopyrane (12c), respectively. The reaction of 1a or 1b0 with 3
equiv of XyNC affords trans-[Pd{C(dNXy)C6H4CH2C(O)NHR-2}I(CNXy)2] (R = H (13a), Me (13b));
the protonation of 13b with HOTf leads to [Pd{C(dNHXy)C6H4CH2C(O)NH2)-2}I(CNXy)2]OTf (14a).
Complexes [Pd{C(dNXy)C6H4{C6H4CH2C(O)NRR0-2}-2}(CNXy)(N∧N)]OTf (N∧N = tmeda,
NRR0 = NHMe (15b), NMe2 (15c); N∧N = dbbpy, NRR0 = NHMe (15b0)) are obtained by reacting
the appropriate complex 2 with 2 equiv of XyNC.
Introduction
Based on its ability to coordinate through the oxygen atom,
the amide unit can act as a directing group in palladium-
catalyzed C-H functionalization reactions,1 which may lead
to C-C2 or C-O3 coupling products. The palladium-cata-
lyzed amidations of aryl halides4-6 are among the most
Amides are commonly employed as substrates or reagents
in a variety of important palladium-mediated syntheses.
*To whom correspondence should be addressed. E-mail: jvs1@um.es,
pgh@um.es, http://www.um.es/gqo; p.jones@tu-bs.de; dbc@um.es
(1) Lyons, T. W.; Sanford, M. S. Chem. Rev. 2010, 110, 1147.
r
2011 American Chemical Society
Published on Web 02/02/2011
pubs.acs.org/Organometallics

1080 Organometallics, Vol. 30, No. 5, 2011
Vicente et al.
significant examples of the amide function participating
directly in the bond formation process. These reactions have
been shown to proceed through aryl(amidate)palladium
complexes that undergo C-N reductive coupling.6-8 In
addition, a number of related Pd(II)-catalyzed amidations
of C-H bonds have been reported, for which the participa-
tion of amidate complexes has also been proposed.9
Our research group is interested in the synthesis of ortho-
functionalized aryl palladium complexes and the study of
their reactivity toward unsaturated molecules, thereby seek-
ing new routes for organic synthesis. In this article, we
describe the synthesis of aryl palladium complexes bearing
an ortho-acetamide group and of several cyclometalated
derivatives, including neutral amidate complexes. We report
also a systematic study of the reactions of these aryl com-
plexes with CO and XyNC (Xy = 2,6-dimethylphenyl). This
type of reactions have been widely studied, as they are involved
in the synthesis of acyl10-15 and iminoacyl11,13-20 palladium
complexes and also in many stoichiometric and catalytic synth-
eses of organic compounds.13-15,20-22 We report in this work
that, depending on the substituents on the amidic nitrogen, these
insertion reactions lead to isoquinoline- or isocoumarin-based
heterocycles resulting from intramolecular C-N or C-O cou-
plings. Both types of heterocyclic structures are present in
numerous natural products and biologically active molecules,
and both the development of suitable synthetic strategies and the
study of their pharmacological activity are the subjects of
intensive research.23
Experimental Section
General Considerations, Materials, and Instrumentation. Un-
less otherwise noted, all preparations were carried out at room
temperature under atmospheric conditions. Synthesis grade
solvents were obtained from commercial sources. Toluene,
CH2Cl2, and THF were degassed and dried using a Pure Solv
MD-5 solvent purification system from Innovative Technology,
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3
acetamide,25 2-(2-iodophenyl)-N-methylacetamide,26 and 2-(2-
iodophenyl)-N,N-dimethylacetamide27 were prepared according
to published procedures. All other reagents were obtained from
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Article
Organometallics, Vol. 30, No. 5, 2011 1081
commercial sources and used without further purification. NMR
spectra were recorded on Bruker Avance 200, 300, or 400 spectro-
meters usually at 298 K, unless otherwise indicated. Chemical shifts
are referred to internal TMS (1H and 13C{1H}) or external 85%
H3PO4 (31P{1H}). The assignments of the 1H and 13C{1H} NMR
spectra were made with the help of HMBC and HMQC experi-
ments. Inserted and coordinated XyNC are denoted by XyNCi and
XyNCc, respectively, and the C6H4 aryl group is denoted as Ar.
Melting points were determined on a Reichert apparatus and are
uncorrected. Elemental analyses were carried out with a Carlo Erba
1106 microanalyzer. Infrared spectra were recorded in the range
4000-200 cm-1 on a Perkin-Elmer Spectrum 100 spectrophot-
ometer using Nujol mulls between polyethylene sheets. High-reso-
lution ESI mass spectra were recorded on an Agilent 6220 Accurate-
Mass TOF LC/MS.
PPh3 (36 mg, 0.14 mmol). The resulting solution was stirred for
1 h, filtered through anhydrous MgSO4, and concentrated (1 mL).
n-Hexane (20 mL) was added to precipitate a white solid, which
was collected by filtration, washed with n-hexane (3 ꢀ 3 mL), and
vacuum-dried to give 3b0. Yield: 88 mg, 69%. Anal. Calcd
for C46H49F3N3O4PPdS: C, 59.13; H, 5.29; N, 4.50; S, 3.43.
Found: C, 58.82; H, 5.25; N, 4.38; S, 3.27. Mp: 156-159 °C. IR
(Nujol, cm-1): ν(NH), 3340; ν(CO), 1670. 1H NMR (400.9 MHz,
CDCl3): δ 8.13 (br s, 2 H, H3, dbbpy), 7.56 (m, 6 H, o-H, Ph),
7.46 (m, 3 H, p-H, Ph), 7.36 (m, 6 H, m-H, Ph), 7.30 (m, 2 H,
H5, dbbpy), 7.21 (d, 3JHH = 6.0 Hz, 1 H, H6, dbbpy), 7.18 (ddd,
5JHH = 1.2 Hz, 4JHH = 3.2 Hz, 3JHH = 8 Hz, 1 H, Ar), 7.10 (d,
3JHH = 7.6 Hz, 1 H, H6, dbbpy), 7.05 (br q, 1 H, NH), 6.92 (m, 2
H, Ar), 6.72 (td, 4JHH = 1.2 Hz, 3JHH = 7.2 Hz, 1 H, Ar), 3.65,
3.01 (AB system, 2JAB = 14.8 Hz, 2 H, CH2), 2.23 (d, 3JHH = 4.8
t
t
In the following, only representative procedures for the
synthesis of each series of analogous Pd complexes are given.
The synthesis and data for the rest of complexes are given in the
Supporting Information.
Hz, 3 H, NMe), 1.38 (s, 9 H, Bu), 1.37 (s, 9 H, Bu). 13C{1H}
NMR (100.8 MHz, CDCl3): δ 171.1 (CO), 164.5, 164.3 (C4,
2
dbbpy), 155.7, 155.6 (C2, dbbpy), 155.4 (d, JCP = 11.0 Hz,
C-Pd), 150.3, 149.9 (C6, dbbpy), 138.7 (d, 3JCP = 2.6 Hz, C, Ar),
134.6 (d, 2JCP = 12.1 Hz, o-C, Ph), 133.3 (d, 2JCP = 5.0 Hz, CH,
Ar), 132.3 (CH, Ar), 131.4 (d, 4JCP = 2.1 Hz, p-C, Ph), 129.0 (d,
Representative Procedure for∧the Syntheses of Complexes
[Pd{C6H4CH2C(O)NRR0-2}}I(N N)] (N∧N = tmeda, NRR0 =
NH2 (1a), NHMe (1b), NMe2 (1c); N∧N = dbbpy, NRR0 =
NHMe (1b0)). Synthesis of 1a. To a suspension of Pd(dba)2
(641 mg, 1.11 mmol) in CH2Cl2 (20 mL) was added tmeda
(0.25 mL, 1.67 mmol), and the mixture was stirred for 10 min
under an N2 atmosphere. 2-(2-Iodophenyl)acetamide (310 mg,
1.19 mmol) was then added, and the stirring was continued for 1 h.
The resulting suspension was filtered through Celite, and the
solution was concentrated (8 mL). Addition of Et2O (25 mL)
led to the precipitation of a pale orange solid, which was filtered
off, washed with Et2O (3 ꢀ 5 mL), and vacuum-dried to give 1a.
Yield: 339 mg, 63%. Anal. Calcd for C14H24IN3OPd: C, 34.77; H,
5.00; N, 8.69. Found: C, 34.69; H, 5.09; N, 8.57. Mp: 170 °C (dec).
3
1JCP = 51.9 Hz, i-C, Ph), 128.9 (d, JCP = 11.0 Hz, m-C, Ph),
126.1 (CH, Ar), 125.0 (CH, Ar), 123.4, 122.9 (C5, dbbpy), 119.9,
119.1 (C3, dbbpy), 46.5 (CH2), 35.5, 35.4 (CMe3), 30.2, 30.1
(CMe3), 25.8 (NMe).
Representative Procedure for the Syntheses of Complexes
[Pd{K2C,N-C6H4CH2C(O)NR-2}(N∧N)] (N∧N = tmeda, R =
H (4a), Me (4b); N∧N = dbbpy, R = Me (4b0)). Synthesis of 4a.
To a solution of 1a (107 mg, 0.22 mmol) in HOtBu (10 mL) were
added KOtBu (50 mg, 0.45 mmol) and CH2Cl2 (2 mL), and the
mixture was stirred for 2 h. The resulting suspension was filtered
through Celite, and the solvent was removed under reduced
pressure. The residue was extracted with CH2Cl2 (20 mL) and
filtered through Celite. Partial evaporation of the filtrate (1 mL)
and slow addition of n-pentane (15 mL) led to the formation of
a colorless precipitate, which was filtered off, washed with
1
IR (Nujol, cm-1): ν(NH), 3372, 3175; ν(CO), 1672. H NMR
(400.9 MHz, CDCl3): δ 7.30 (dd, 4JHH = 1.6 Hz, 3JHH = 7.6 Hz,
1 H, Ar), 7.06 (dd, 4JHH = 2.0 Hz, 3JHH = 7.6 Hz, 1 H, Ar), 6.90
(td, 4JHH = 2.0 Hz, 3JHH = 7.6 Hz, 1 H, Ar), 6.85 (td, 4JHH = 1.6
Hz, 3JHH = 7.6 Hz, 1 H, Ar), 6.26 (br, 1 H, NH), 5.26 (br, 1 H,
n-pentane (3 ꢀ 3 mL), and vacuum-dried to give 4a H2O. Yield:
3
58 mg, 74%. Anal. Calcd for C14H25N3O2Pd: C, 44.99; H, 6.74; N,
11.24. Found: C, 44.95; H, 6.87; N, 11.17. Mp: 185-190 °C. IR
(Nujol, cm-1): ν(NH), 3385, 3269; ν(CO), 1577. 1H NMR (400.9
MHz, CDCl3): δ 7.23-7.19 (m, 1 H, Ar), 6.96-6.92 (m, 1 H, Ar),
6.92-6.86 (m, 2 H, Ar), 3.85 (br, 1 H, NH), 3.72 (s, 2 H, CH2,
acetamide), 2.79-2.74 (m, 2 H, CH2, tmeda), 2.66 (s, 6 H, Me,
tmeda), 2.60 (m, 2 H, CH2, tmeda), 2.56 (s, 6 H, Me, tmeda), 1.83
(s, 2 H, H2O). 13C{1H} NMR (100.8 MHz, CDCl3): δ 179.0 (CO),
148.5 (C, Ar), 143.2 (C, Ar), 132.2 (CH, Ar), 126.0 (CH, Ar), 124.3
(CH, Ar), 123.7 (CH, Ar), 63.1 (CH2, tmeda), 58.0 (CH2, tmeda),
50.5 (Me, tmeda), 50.2 (CH2, acetamide), 48.0 (Me, tmeda).
[Pd{C6H4CH2C(O)NHMe-2}{CH(CN)2}(dbbpy)] (5b0). To a
solution of 4b0 (95.6 mg, 0.183 mmol) in CH2Cl2 (10 mL) was
added malononitrile (12.2 mg, 0.185 mmol), and the mixture
was stirred for 1 h. The resulting colorless solution was con-
centrated (1 mL), and n-pentane (30 mL) was slowly added,
whereupon a colorless solid precipitated, which was filtered off,
washed with n-pentane (3 ꢀ 5 mL), and vacuum-dried to give
2
NH), 4.76, 3.77 (AB system, JHH = 14.4 Hz, 2 H, CH2,
acetamide), 2.89-2.83 (m, 1 H, CH2, tmeda), 2.73 (s, 3 H, Me,
tmeda), 2.70 (s, 3 H, Me, tmeda), 2.72-2.62 (m, 2 H, CH2, tmeda),
2.58-2.50 (m, 1 H, CH2, tmeda), 2.43 (s, 3 H, Me, tmeda), 2.18 (s,
3 H, CH3, tmeda). 13C{1H} NMR (100.8 MHz, CDCl3): δ 175.6
(CO), 145.1 (C, Ar), 140.0 (C, Ar), 137.2 (CH, Ar), 128.1 (CH,
Ar), 125.9 (CH, Ar), 124.1 (CH, Ar), 62.6 (CH2, tmeda), 58.7
(CH2, tmeda), 50.9 (Me, tmeda), 50.8 (Me, tmeda), 49.6 (Me,
tmeda), 49.4 (Me, tmeda), 48.2 (CH2, acetamide).
Representative Procedure for the Syntheses o∧f Complexes
[Pd{K2C,O-C6H4CH2C(O)NRR0-2}(N∧N)]OTf (N N = tmeda,
NRR0 = NH2 (2a), NHMe (2b), NMe2 (2c); N∧N = dbbpy,
NRR0 = NHMe (2b0)). Synthesis of 2a. To a solution of 1a (82
mg, 0.17 mmol) in acetone (20 mL) was addedAgOTf (52 mg, 0.20
mmol). The resulting suspension was stirred for 1 h and filtered
through Celite. Partial evaporation of the filtrate (1 mL) and
addition of Et2O (20 mL) led to the precipitation of a colorless
solid, which was collected by filtration, washed with Et2O (3 ꢀ 3
mL), and vacuum-dried to give 2a. Yield: 74 mg, 86%. Anal.
Calcd for C15H24F3N3O4PdS: C, 35.62; H, 4.78; N, 8.31; S, 6.34.
Found: C, 35.78; H, 4.73; N, 8.29; S, 6.01. Mp: 190-192 °C (dec).
IR (Nujol, cm-1): ν(NH), 3400, 3330, 3202; ν(CO), 1654. 1H
NMR (400.9 MHz, (CD3)2CO): δ 8.70 (br, 1 H, NH), 8.20 (br, 1
H, NH), 7.32 (m, 1 H, Ar), 7.01-6.93 (m, 3 H, Ar), 4.22 (s, 2 H,
CH2, acetamide), 3.10 (m, 2 H, CH2, tmeda), 2.87 (m, 2 H, CH2,
tmeda), 2.84 (s, 6 H, Me, tmeda), 2.67 (s, 6 H, Me, tmeda).
13C{1H} NMR (75.5 MHz, (CD3)2CO): δ 181.6 (CO), 148.3 (C,
Ar), 135.5 (C, Ar), 133.3 (CH, Ar), 127.2 (CH, Ar), 126.4 (CH,
Ar), 125.4 (CH, Ar), 65.5 (CH2, tmeda), 57.8 (CH2, tmeda), 51.9
(Me, tmeda), 48.4 (CH2, acetamide), 47.5 (Me, tmeda).
5b0 0.25H2O. Yield: 87 mg, 81%. Anal. Calcd for C30H35.5
-
3
N5O1.25Pd: C, 60.81; H, 6.04; N, 11.82. Found: C, 60.67; H, 6.19;
N, 11.93. Mp: 169-172 °C (dec). IR (Nujol, cm-1): ν(NH),
1
3371; ν(CN), 2213, 2206; ν(CO), 1674. H NMR (400.9 MHz,
3
CDCl3): δ 8.89 (d, JHH = 5.6 Hz, 1 H, H6, dbbpy), 8.03 (d,
4JHH = 1.6 Hz, 1 H, H3, dbbpy), 7.98 (d, 4JHH = 1.6 Hz, 1 H,
H3, dbbpy), 7.68 (dd, 4JHH = 1.6 Hz, 3JHH = 5.6 Hz, 1 H, H5,
dbbpy), 7.53 (dd, 4JHH = 1.6 Hz, 3JHH = 7.2 Hz, 1 H, Ar), 7.46
(d, 3JHH = 5.6 Hz, 1 H, H6, dbbpy), 7.27 (m, 1 H, H5, dbbpy),
7.23 (dd, 4JHH = 2 Hz, 3JHH = 6.8 Hz, 1 H, Ar), 7.07 (m, 2 H,
Ar), 5.96 (br q, 3JHH = 4.4 Hz, 1 H, NH), 4.03, 3.74 (AB system,
2JAB = 15.2 Hz, 2 H, CH2), 2.71 (s, 1 H, CH(CN)2), 2.55 (d,
3JHH = 4.8 Hz, 3 H, NMe), 1.64 (s, 0.5 H, H2O), 1.46 (s, 9 H,
tBu), 1.38 (s, 9 H, tBu). 13C{1H} APT NMR (75.5 MHz, CDCl3):
δ 172.4 (CO), 164.2, 163.9 (C4, dbbpy), 155.9 (C, Ar), 155.3,
[Pd{C6H4CH2C(O)NHMe-2}(dbbpy)(PPh3)]OTf (3b0). To a
solution of 2b0 (91 mg, 0.14 mmol) in CH2Cl2 (10 mL) was added

1082 Organometallics, Vol. 30, No. 5, 2011
Vicente et al.
154.4 (C2, dbbpy), 150.5, 149.4 (C6, dbbpy), 139.2 (C, Ar), 135.4
(CH, Ar), 129.9 (CH, Ar), 126.3 (CH, Ar), 124.5 (CH, Ar),
124.3, 123.8 (C5, dbbpy), 121.1, 120.6 (CN), 118.5, 118.4 (C3,
dbbpy), 47.1 (CH2), 35.6, 35.5 (CMe3), 30.3, 30.2 (CMe3), 26.1
(NMe) (CH(CN)2 not observed).
C10H10NO2 [M þ H]þ requires 176.0706, found: 176.0711,
error = 3.01 ppm. 1H NMR (400.9 MHz, CDCl3): δ 8.07 (ddd,
5JHH = 0.8 Hz, 4JHH = 1.2 Hz, 3JHH = 8.0 Hz, 1 H, H8), 7.51
(ddd, 4JHH = 1.2 Hz, 3JHH = 7.2 Hz, 3JHH = 8.0 Hz, 1 H, H6),
7.18 (br d, 3JHH = 8.0 Hz, 1 H, H5), 7.12 (ddd, 4JHH = 1.2 Hz,
3JHH = 7.2 Hz, 3JHH = 8.0 Hz, 1 H, H7), 5.19 (s, 1 H, H4), 4.24
(br s, 1 H, NH), 2.86 (d, 3JHH = 5.2 Hz, 3 H, Me). 13C{1H} NMR
(100.8 MHz, CDCl3): δ161.9(CO), 156.8 (C3), 141.8 (C4a), 134.9
(C6), 129.6 (C8), 123.4 (C5), 123.2 (C7), 115.4 (C8a), 76.0 (C4),
28.8 (Me).
Representative Procedure for the Syntheses of [Pd{C(O)C6H4-
CH2C(O)NRR0-2}I(N∧N)] (N∧N = tmeda, NRR0 = NH2 (6a),
NHMe (6b), NMe2 (6c); N∧N = dbbpy, NRR0 = NHMe
(6b0)). Synthesis of 6a. CO was bubbled through a stirred
solution of 1a (105 mg, 0.18 mmol) in CH2Cl2 (10 mL)
at -17 °C for 30 min, and the resulting solution was filtered
through anhydrous MgSO4. Partial evaporation of the filtrate (1
mL) and addition of Et2O (20 mL) led to the precipitation of a
yellow solid, which was collected by filtration, washed with Et2O
(3 ꢀ 3 mL), and vacuum-dried to give 6a. Yield: 80 mg, 72%.
Anal. Calcd for C15H24IN3O2Pd: C, 35.21; H, 4.73; N, 8.21.
Found: C, 35.08; H, 4.73; N, 7.83. Mp: 165 °C (dec). IR (Nujol,
3-(Dimethylamino)-1H-2-benzopyran-1-one (8c). A solution
of 1c (61 mg, 0.12 mmol) in CHCl3 (20 mL) was stirred under
a CO atmosphere (1.4 bar) at 50 °C for 3 days. A black
precipitate of Pd gradually formed. The solvent was evaporated
under vacuum, the residue was extracted with Et2O (6 ꢀ 5 mL),
and the extracts were filtered through Celite. Compound 8c was
obtained as a bright yellow solid after evaporation of the solvent
under vacuum. Yield: 23 mg, 93%. Mp: 67-71 °C. IR (Nujol,
cm-1): ν(COO), 1752, 1734. HRMS (ESIþ, m/z): exact mass
calcd for C11H12NO2 [M þ H]þ requires 190.0863, found
1
cm-1): ν(NH), 3396, 3187; ν(CO), 1671, 1635. H NMR (400.9
MHz, CDCl3): δ 9.14 (dd, 4JHH = 1.2 Hz, 3JHH = 7.6 Hz, 1 H,
Ar), 7.51 (td, 4JHH = 1.2 Hz, 3JHH = 7.6 Hz, 1 H, Ar), 7.38 (td,
4JHH = 1.6 Hz, 3JHH = 7.6 Hz, 1 H, Ar), 7.23 (dd, 4JHH = 0.8 Hz,
3JHH = 7.6 Hz, 1 H, H3, Ar), 6.34 (s, 1 H, NH), 5.19 (s, 1 H, NH),
3.76 (s, 2 H, CH2, acetamide), 2.73 (m, 2 H, CH2, tmeda), 2.60 (s, 3
H, Me, tmeda), 2.55 (m, 2 H, CH2, tmeda), 2.47 (s, 3 H, Me,
tmeda). 13C{1H} NMR (100.8 MHz, CDCl3): δ 173.3 (CO), 139.7
(CH, Ar), 138.4 (C, Ar), 131.4 (CH, Ar), 131.2 (CH, Ar), 130.7 (C,
Ar), 127.0 (CH, Ar), 61.9 (CH2, tmeda), 57.7 (CH2, tmeda), 50.4
(Me, tmeda), 49.0 (Me, tmeda), 41.6 (CH2) (PdC not observed).
Isoquinoline-1,3(2H,4H)-dione (7a). A solution of 2a (105 mg,
0.21 mmol) in acetone (15 mL) was stirred under a CO atmo-
sphere (1.4 bar) at room temperature for 3 h. A black precipitate
of Pd gradually formed. The solvent was evaporated under
vacuum, the residue was extracted with CH2Cl2 (6 ꢀ 5 mL),
and the extracts were filtered through anhydrous MgSO4. The
filtrate was evaporated to dryness; the yellow residue was stirred
in water (15 mL), collected by filtration, and washed with water
(5 ꢀ 3 mL). The crude product was recrystallized from ethanol
to give 7a as a pale yellow microcrystalline solid. Yield: 17 mg,
51%. Mp: 224-236 °C (lit. 217,28 233-235 °C29). The 1H NMR
data are in agreement with those reported in the literature.28,29
2-Methylisoquinoline-1,3(2H,4H)-dione (7b). A solution of 2b
(111 mg, 0.21 mmol) and NEt3 (80 μL, 0.57 mmol) in acetone
(15 mL) was stirred under a CO atmosphere (1.4 bar) at room
temperature for 3 h. A black precipitate of Pd gradually formed.
The solvent was evaporated under vacuum, the residue was
extracted with CH2Cl2 (6 ꢀ 5 mL), and the extracts were filtered
through anhydrous MgSO4. The yellow filtrate was evaporated
to dryness, the residue was extracted with n-hexane (20 þ 6 ꢀ
5 mL), and the extracts were filtered through anhydrous
MgSO4. The solvent was then removed under reduced pressure
to give 7b as a colorless solid. Yield: 25 mg, 67%. Mp: 120-
122 °C (lit.30 120-121 °C). The 1H NMR data are in agreement
with those reported in the literature.30
1
190.0874, error = 5.99 ppm. H NMR (400.9 MHz, CDCl3):
δ 8.06 (m, 1 H, H8), 7.47 (ddd, 4JHH = 1.2 Hz, 3JHH = 7.2 Hz,
3JHH = 8.4 Hz, 1 H, H6), 7.14 (br d, 3JHH = 8.4 Hz, 1 H, H5),
7.08 (ddd, 4JHH = 1.2 Hz, 3JHH = 7.2 Hz, 3JHH = 8.4 Hz, 1 H,
H7), 5.21 (s, 1 H, H4), 2.99 (s, 6 H, Me). 13C{1H} NMR (100.8
MHz, CDCl3): δ 161.9 (CO), 157.0 (C3), 142.1 (C4a), 134.7 (C6),
129.6 (C8), 123.4 (C5), 122.9 (C7), 114.5 (C8a), 77.8 (C4), 37.7
(Me).
N,3,3-Trimethyl-1-oxo-3,4-dihydro-1H-2-benzopyrane-4-car-
boxamide (9). A solutionof2b0 (103 mg, 0.15 mmol) inacetone (15
mL) was stirred under a CO atmosphere (1.4 bar) for 90 min. The
resulting black suspension was filtered through Celite, and the
filtrate was concentrated to dryness. The residue was dissolved in
CH2Cl2 (15 mL), Et3N (42 μL, 0.30 mmol) was added, and the
solution was stirred for 1 h. Partial evaporation of the solvent
(2 mL) and addition of Et2O (20 mL) led to the precipitation of a
colorless solid, which was filtered off, washed with Et2O (3 ꢀ
3 mL), and vacuum-dried to give 9. Yield: 24 mg, 67%. Mp:
243-244 °C. IR (Nujol, cm-1): ν(NH), 3306; ν(CO), 1710, 1642.
HRMS (ESIþ, m/z): exact mass calcd for C13H16NO3 [M þ H]þ
requires 234.1125, found 234.1126, error = 0.54 ppm. 1H NMR
(400.9 MHz, CDCl3): δ 8.17 (d, 3JHH = 7.6 Hz, 1 H, H8), 7.61 (t,
3JHH = 7.6Hz, 1 H, H6), 7.48 (t, 3JHH =7.6 Hz, 1 H, H7), 7.33 (d,
3JHH = 7.6 Hz, 1 H, H5), 5.56 (br s, 1 H, NH), 3.72 (s, 1 H, H4),
2.79 (d, 3JHH = 4.8 Hz, 3 H, NMe), 1.60 (s, 3 H, Me2C), 1.44 (s,
3 H, Me2C). 13C{1H} APT NMR (75.5 MHz, CDCl3): δ 169.4
(CO,amide), 164.3(C1), 136.9(C4a), 134.5(C6), 130.6(C8), 128.8
(C7), 128.2 (C5), 124.2 (C8a), 81.5 (C3), 55.5 (C4), 28.0 (Me2C),
26.7 (NMe), 25.8 (Me2C).
[Pd{C(dNXy)C6H4CH2C(O)NHMe-2}I(dbbpy)] (10b0). To a
solution of 1b0 (114 mg, 0.18 mmol) in CH2Cl2 (7 mL) was added
XyNC (23 mg, 0.18 mmol); the mixture was stirred for 1 h and
concentrated under reduced pressure (2 mL). n-Pentane (30 mL)
was then added to precipitate a yellow solid, which was collected
by filtration, washed with n-pentane (3 ꢀ 3 mL), and vacuum-
3-(Methylamino)-1H-2-benzopyran-1-one (8b). A solution of
2b (81 mg, 0.16 mmol) in acetone (15 mL) was stirred under a CO
atmosphere (1.4 bar) for 2.5 h. A black precipitate of Pd
gradually formed. The solvent was evaporated under vacuum,
the residue was extracted with Et2O (6 ꢀ 5 mL), and the
combined extracts were filtered through Celite. The filtrate
was washed with a saturated aqueous solution of K2CO3 (3 ꢀ
5 mL), dried over anhydrous Na2SO4, and evaporated under
reduced pressure to give 8b as a bright yellow solid. Yield: 16 mg,
59%. Mp: 116-119 °C. IR (Nujol, cm-1): ν(N-H), 3303;
ν(COO), 1719, 1651. HRMS (ESIþ, m/z): exact mass calcd for
dried to give 10b0 0.25CH2Cl2. Yield: 110 mg, 78%. Anal. Calcd
3
for C36.25H43.5Cl0.5IN4OPd: C, 54.27; H, 5.47; N, 6.98. Found:
C, 54.01; H, 5.18; N, 7.17. Mp: 155-158 °C. IR (Nujol, cm-1):
ν(CdN), 1567; ν(CO), 1665. 1H NMR (400.9 MHz, CDCl3): δ
9.34 (d, 3JHH = 6.0 Hz, 1 H, H6, dbbpy), 9.00 (dd, 4JHH = 1.6
Hz, 3JHH = 7.2 Hz, 1 H, Ar), 7.96 (d, 3JHH = 6.0 Hz, 1 H, H6,
dbbpy), 7.93 (overlapped broad signal, 1 H, NH), 7.91 (d,
4
4JHH = 1.6 Hz, 1 H, H3, dbbpy), 7.87 (d, JHH = 1.6 Hz, 1
H, H3, dbbpy), 7.46 (dd, 4JHH = 1.6 Hz, 3JHH = 7.2 Hz, 1 H,
Ar), 7.40 (dd, 4JHH = 1.6 Hz, 3JHH = 5.6 Hz, 1 H, H5, dbbpy),
7.31-7.38 (m, 3 H, H5 dbbpy þ Ar), 6.99-6.90 (m, 3 H, Xy),
5.30 (s, 0.5 H, CH2Cl2), 4.00 (br, 2 H, CH2), 2.60 (d, 3JHH = 4.8
Hz, 3 H, NMe), 2.23 (s, 6 H, Me, Xy), 1.38, 1.37 (both s, 9 H
each, tBu). 13C{1H} NMR (100.8 MHz, CDCl3): δ 184.0 (CdN),
172.2 (CO), 163.6, 163.2 (C4, dbbpy), 155.4, 152.9 (C2, dbbpy),
(28) Huh, D. H.; Jeong, J. S.; Lee, H. B.; Ryu, H.; Kim, Y. G.
Tetrahedron 2002, 58, 9925.
(29) Deady, L. W.; Quazi, N. H. J. Heterocycl. Chem. 1994, 31, 793.
(30) Malamas, M. S.; Hohman, T. C.; Millen, J. J. Med. Chem. 1994,
37, 2043.

Article
Organometallics, Vol. 30, No. 5, 2011 1083
152.9 (C6, dbbpy), 149.7 (i-C, Xy), 149.6 (C6, dbbpy), 140.0 (C,
Ar), 136.7 (CH, Ar), 131.8 (C, Ar), 130.2 (CH, Ar), 128.5 (CH,
Ar), 128.0 (CH, Xy), 126.5 (CH, Ar), 123.8, 123.5 (C5, dbbpy),
123.3 (CH, Xy), 118.6, 117.8 (C3, dbbpy), 41.7 (CH2), 35.5, 35.4
(CMe3), 30.3, 30.2 (CMe3), 26.0 (NMe), 20.7 (Me, Xy) (o-C of
Xy and CH2Cl2 not observed).
Representative Procedure for the Syntheses of Complexes
trans-[Pd{C(dNXy)C6H4CH2C(O)NRR0-2}I(CNXy)2] (NRR0 =
NH2 (13a), NHMe (13b)). Synthesis of 13a. To a solution of 1a
(93 mg, 0.19 mmol) in CH2Cl2 (20 mL) was added XyNC (78 mg,
0.59 mmol). The mixture was stirred at room temperature for
30 min and concentrated under reduced pressure (3 mL). The
addition of n-pentane (15 mL) led to the precipitation of a yellow
solid, which was filtered off, washed with n-pentane (3 ꢀ 3 mL),
1-(2,6-Dimethylphenylimino)-1,2-dihydroisoquinolin-3(4H)-
one (11a). To a solution of 1a (183 mg, 0.38 mmol) in CH2Cl2
(25 mL) was added XyNC (49.6 mg, 0.38 mmol). The mixture
was stirred for 30 min, concentrated under reduced pressure
(10 mL), and then stirred for 24 h, whereupon a black suspen-
sion formed. The solvent was removed under vacuum, the
residue was extracted with Et2O (10 ꢀ 5 mL), and the combined
extracts were filtered through anhydrous MgSO4. Evaporation of
the solvent under reduced pressure led to the precipitation of 11a
as a colorless solid. Yield: 59 mg, 58%. Mp: 149-151 °C. IR
(Nujol, cm-1): ν(N-H), 3360; ν(CO), 1694; ν(CdN), 1645.
HRMS (ESIþ, m/z): exact mass calcd for C17H17N2O [M þ
and vacuum-dried to give 13a H2O. Yield: 134 mg, 92%. Anal.
3
Calcd for C35H37IN4O2Pd: C, 53.96; H, 4.79; N, 7.19. Found: C,
53.84; H, 4.59; N, 7.25. Mp: 122-127 °C (dec). IR (Nujol, cm-1):
ν(CtN), 2180; ν(CO), 1687; ν(CdN), 1586. 1H NMR (400.9
MHz, CDCl3): δ 8.24 (d, 3JHH = 8.0 Hz, 1 H, Ar), 7.72 (br, 1 H,
NH), 7.46 (m, 2 H, Ar), 7.35 (td, 4JHH = 1.6 Hz, 3JHH = 7.6 Hz, 1
H, Ar), 7.23 (t, 3JHH = 7.6 Hz, 2 H, p-H, XyNCc), 7.08 (d, 3JHH
=
7.6 Hz, 4 H, m-H, XyNCc), 6.96 (s, 3 H, XyNCi), 5.07 (br, 1 H,
NH), 3.88 (s, 2 H, CH2), 2.22 (s, 12 H, Me, XyNCc), 2.21 (s, 6 H,
Me, XyNCi), 1.66 (br s, 2 H, H2O). 13C{1H} APT NMR (100.8
MHz, CDCl3): δ 183.6 (CdN), 173.7 (CO), 149.3 (i-C, XyNCi),
144.6 (C, Ar), 135.7 (o-C, XyNCc), 132.7 (CH, Ar), 130.7 (CH,
Ar), 130.2 (CH, XyNCc), 130.0 (C, Ar), 129.0 (CH, Ar), 128.4
(CH, XyNCi), 128.1 (CH, XyNCc), 127.3 (o-C, XyNCi), 127.1
(CH, Ar), 124.2 (CH, XyNCi), 41.6 (CH2), 19.2 (Me, XyNCi), 18.7
(Me, XyNCc); CtN and i-C of XyNCc not observed.
1
H]þ requires 265.1335, found 265.1333, error = 0.75 ppm. H
NMR (400.9 MHz, CDCl3): δ 8.52 (dd, 4JHH = 0.8 Hz, 3JHH
=
7.6 Hz, 1 H, H8), 7.63 (br, 1 H, NH), 7.55 (td, 4JHH = 1.2 Hz,
3JHH = 7.6 Hz, 1 H, H6), 7.46 (br t, 3JHH = 7.6 Hz, 1 H, H7), 7.28
3
3
(br d, JHH = 7.6 Hz, 1 H, H5), 7.09 (br d, JHH = 7.6 Hz,
2 H, m-H, Xy), 6.97 (br t, 3JHH = 7.6 Hz, 1 H, p-H, Xy), 3.97 (s,
2 H, H4), 2.08 (s, 6 H, Me, Xy). 13C{1H} NMR (100.8 MHz,
CDCl3): δ 168.4 (CO), 145.0 (CdN), 143.6 (i-C, Xy), 133.0 (C4a),
132.0 (C6), 128.6 (m-C, Xy), 127.7 (o-C, Xy), 127.65 (C5),
127.60 (C7), 127.1 (C8), 125.8 (C8a), 124.2 (p-C, Xy), 35.8 (C4),
17.9 (Me, Xy).
trans-[Pd{C(dNHXy)C6H4CH2C(O)NH2)-2}I(CNXy)2]OTf
(14a). To a solution of 13a (159.2 mg, 0.21 mmol) in CH2Cl2 (15
mL) was added HOTf (18.3 μL, 0.21 mmol), and the mixture was
stirred for 1 h. The resulting solution was concentrated under
reduced pressure (1 mL), and Et2O (30 mL) was added to
precipitate a yellow solid, which was filtered off, washed with
Et2O (3 ꢀ 3 mL), and vacuum-dried to give 14a. Yield: 173.0 mg,
91%. Anal. Calcd for C36H36F3IN4O4PdS: C, 47.46; H, 3.98; N,
6.15; S, 3.52. Found: C, 47.73; H, 3.82; N, 6.18; S, 3.48. Mp:
143-145 °C (dec). IR (Nujol, cm-1): ν(CtN), 2199; ν(CO),
1-(2,6-Dimethylphenylimino)-2-methyl-1,2-dihydroisoquinolin-
3(4H)-one (11b). To a solution of 1b (198 mg, 0.40 mmol) in
CHCl3 (20 mL) was added XyNC (52 mg, 0.40 mmol); the
mixture was refluxed for 3 h and then stirred at room temperature
for 60 h. The resulting black suspension was worked up as
described for 11a to give 11b as a pale yellow solid. Yield:
89 mg, 80%. Mp: 108-112 °C. IR (Nujol, cm-1): ν(CO), 1697;
ν(CdN), 1644. HRMS (ESIþ, m/z): exact mass calcd for
C18H19NO2 [M þ H]þ requires 279.1492, found 279.1487,
1
1650; ν(CdN), 1588. H NMR (400.9 MHz, CDCl3): δ 16.36
(br, 1 H, NH, iminium), 9.03 (br, 1 H, NH, acetamide), 8.36 (dd,
4JHH = 2.1 Hz, 3JHH = 7.2 Hz, 1 H, Ar), 7.95 (dd, 4JHH = 2.1
Hz, 3JHH = 7.2 Hz, 1 H, Ar), 7.65 (m, 2 H, Ar), 7.31 (t, 3JHH
=
7.5 Hz, 3 H, p-H, Xy), 7.13 (d, 3JHH = 7.5 Hz, 6 H, m-H, Xy),
6.04 (br, NH, acetamide), 4.06 (s, 2 H, CH2), 2.35 (s, 6 H, Me,
Xy, iminium), 2.19 (s, 12 H, Me, XyNCc). 13C{1H} NMR (75.5
MHz, CDCl3): δ 176.5 (CO), 142.1 (C, Ar), 139.7 (i-C, Xy,
iminium), 136.0 (o-C, XyNCc), 134.5 (CH, Ar), 133.9 (CH, Ar),
133.1 (CH, Ar), 132.8 (o-C, Xy, iminium), 131.3 (CH, XyNCc),
130.0 (C, Ar), 129.7 (CH, Ar), 129.4 (CH, Xy, iminium), 128.5
(CH, XyNCc), 39.2 (CH2), 18.9 (Me, Xy, iminium), 18.6 (Me,
XyNCc); CdN, CtN, and i-C of XyNCc not observed.
1
error = 1.79 ppm. H NMR (400.9 MHz, CDCl3): δ 7.35 (td,
4JHH = 1.2 Hz, 3JHH = 7.6 Hz, 1 H, H6), 7.23 (br d, 3JHH = 7.6
Hz, 1 H, H5), 7.17 (br, 1 H, H8), 7.05 (br d, 3JHH = 7.6 Hz, 2 H,
m-H, Xy), 6.99 (br t, 3JHH = 4.8 Hz, H7), 6.90 (br t, 3JHH = 7.6
Hz, 1 H, p-H, Xy), 3.93 (s, 2 H, H4), 3.50 (s, 3 H, NMe), 2.00
(s, 6 H, Me, Xy). 13C{1H} NMR (75.5 MHz, CDCl3): δ 169.0
(CO), 147.8 (CdN), 146.2 (i-C, Xy), 132.2 (C4a) 131.1 (C6), 128.4
(m-C, Xy), 127.7 (C5), 127.0 (C7), 126.7 (C8), 126.2 (br, C8a),
125.2 (o-C, Xy), 122.6 (p-C, Xy), 37.4 (C4), 29.6 (NMe), 18.2
(Me, Xy).
Representative Procedure for the Syntheses∧of Complex∧es [Pd-
{C(dNXy)C6H4CH2C(O)NRR0-2}(CNXy)(N N]OTf (N N =
tmeda, NRR0 = NHMe (15b), NMe2 (15c); N∧N = dbbpy,
NRR0 = NHMe (15b0)). Synthesis of 15b. To a solution of 2b
(125 mg, 0.24 mmol) in CH2Cl2 (15 mL) was added XyNC (63 mg,
0.48 mmol), and the resulting yellow solution was stirred for 2.5 h,
filtered through Celite, and concentrated under reduced pressure
(2 mL). The addition of Et2O (25 mL) led to the precipitation of a
yellow solid, which was filtered off, washed with Et2O (5 ꢀ 3 mL),
1-(2,6-Dimethylphenylimino)-3-(N,N-dimethylamino)-1H-2-
benzopyran (12c). To a solution of 1c (91 mg, 0.17 mmol) in
CHCl3 (15 mL) was added XyNC (23 mg, 0.17 mmol), and the
mixture was stirred at 60 °C for 24 h. Gradual formation of
colloidal Pd was observed. The solvent was removed under
vacuum, the residue was extracted with Et2O (6 ꢀ 5 mL), and
the combined extracts were filtered through anhydrous MgSO4.
Compound 12c was isolated as a yellow oil after evaporation of
the solvent under reduced pressure. Yield: 51 mg, 98%. IR
(Nujol, cm-1): ν(CdN), 1673, 1623. HRMS (ESIþ, m/z): exact
mass calcd for C19H21N2O [M þ H]þ requires 293.1648, found
293.1652, error = 1.09 ppm. 1H NMR (400.9 MHz, CDCl3): δ
and vacuum-dried to give 15b 0.5H2O. Yield: 126 mg, 66%. Anal.
3
Calcd for C34H45F3N5O4.5PdS: C, 51.61; H, 5.73; N, 8.85; S, 4.05.
Found: C, 51.51; H, 5.76; N, 8.86; S, 3.85. Mp: 103-104 °C . IR
(Nujol, cm-1): ν(NH), 3327; ν(CtN), 2182; ν(CO), 1662;
1
3
ν(CdN), 1583. H NMR (300.1 MHz, CDCl3): δ 8.20 (d, JHH
3
4
= 7.5Hz, 1 H, Ar), 7.59-7.39 (m, 4 H, Arþ NH), 7.32 (t, 3JHH
=
8.26 (d, JHH = 7.6 Hz, 1 H, H8), 7.38 (ddd, JHH = 1.2 Hz,
3JHH = 7.2 Hz, 3JHH = 7.6 Hz, 1 H, H6), 7.10-7.06 (m, 2 H, H7
=
7.5 Hz, 1 H, p-H, XyNCc), 7.14 (d, JHH = 7.5 Hz, 1 H, m-H,
XyNCc), 7.04-6.90 (m, 3 H, XyNCi), 3.81 (br, 2 H, CH2,
acetamide), 2.80 (br, 4 H, CH2, tmeda), 2.59 (d, 3JHH = 4.5 Hz,
3 H, NMe, acetamide), 2.42 (br s, 12 H, Me, tmeda), 2.17 (br s, 12
H, Me, XyNC), 1.84 (br s, 1 H, H2O). 13C{1H} NMR (75.5 MHz,
CDCl3):δ180.4(CdN), 171.3 (CO), 149.5(i-C, XyNCi), 138.2 (C,
Ar), 135.3 (o-C, XyNCc), 132.2 (CH, Ar), 131.9 (C, Ar), 131.0
(CH, Ar), 130.9 (CH, XyNCc), 130.0 (CH, Ar), 128.5 (CH,
3
þ H5), 7.03 (br d, 3JHH = 7.6 Hz, 2 H, m-H, Xy), 6.87 (t, 3JHH
7.6 Hz, 1 H, p-H, Xy), 4.94 (s, 1 H, H4), 2.60 (s, 6 H, NMe2), 2.14
(s, 6 H, Me, Xy). 13C{1H} NMR (100.8 MHz, CDCl3): δ 155.6
(C3), 148.8 (CdN), 145.4 (i-C, Xy), 138.2 (C4a), 132.4 (C6), 128.1
(o-C, Xy), 127.4 (m-C, Xy), 127.3 (C8), 123.1 (C7), 122.9 (C5),
122.4 (p-C, Xy), 117.8 (C8a), 76.0 (C4), 37.1 (NMe2), 18.2
(Me, Xy).

1084 Organometallics, Vol. 30, No. 5, 2011
Vicente et al.
Table 1. Crystallographic Data for 1b0, 2b0 Me2CO, 3b0, and 4b0 0.5CH2Cl2
3
3
1b0
2b0 Me2CO
3b0
4b0 0.5CH2Cl2
3
3
formula
fw
T (K)
λ (A)
cryst syst
C27H34IN3OPd
649.87
100(2)
0.71073
orthorhombic
Pna21
13.4414(6)
11.7373(5)
17.4652(8)
90
90
90
2755.4(2)
4
1.567
1.817
0.0203
0.0473
C31H40F3N3O5PdS
730.12
100(2)
0.71073
triclinic
P1
10.2621(5)
13.5328(7)
14.1804(7)
63.950(2)
71.051(2)
72.364(2)
1643.30(14)
2
C46H49F3N3O4PPdS
934.31
100(2)
0.71073
triclinic
P1
12.2756(5)
13.6966(5)
14.0469(5)
70.198(4)
82.776(4)
76.276(4)
2156.00(14)
2
C27.5H34ClN3OPd
564.43
100(2)
0.71073
triclinic
P1
12.1373(5)
13.4080(6)
16.7547(7)
95.000(2)
99.522(2)
105.510(2)
2566.23(19)
4
˚
space group
˚
a (A)
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
3
˚
V (A )
Z
F
calcd (Mg m-3
)
1.476
0.688
0.0484
0.1189
1.439
0.576
0.0291
0.0703
1.461
0.852
0.0532
0.1082
μ (mm-1
R1a
)
wR2b
P
P
P
P
a R1 =
Fo|-|Fc
/
|Fo| for reflections with I > 2σ(I). b wR2 = [ [w(Fo2 - Fc2)2]/ [w(Fo2)2]0.5 for all reflections; w-1 = σ2(F2) þ (aP)2 þ bP,
2
where P = (2Fc þ Fo2)/3 and a and b are constants set by the program.
Table 2. Crystallographic Data for 5b0, 6b0, 8b, 9, and 10b0
5b0
6b0
8b
9
10b0
formula
fw
T (K)
λ (A)
cryst syst
C30H35N5OPd
588.03
100(2)
0.71073
monoclinic
P21/c
10.6664(2)
26.7297(3)
10.2585(2)
90
108.641(3)
90
2771.36(8)
4
1.409
0.701
0.0224
0.0533
C28H34IN3O2Pd
677.88
103(2)
1.54184
monoclinic
P21/c
19.8663(6)
10.1395(3)
14.4269(5)
90
109.676(4)
90
2736.39(15)
4
1.645
14.554
0.0342
0.0921
C10H9NO2
175.18
110(2)
0.71073
monoclinic
P21/c
19.5562(5)
11.9837(3)
7.2383(2)
90
100.198(4)
90
1669.55(8)
8
1.394
C13H15NO3
233.26
100(2)
0.71073
monoclinic
Pn
7.8580(2)
9.7895(2)
8.1530(2)
90
108.008(3)
90
596.45(2)
2
1.299
C36H43IN4OPd
781.04
100(2)
0.71073
monoclinic
C2/c
31.3723(16)
12.4240(6)
21.9332(11)
90
118.671(2)
90
7500.7(6)
8
1.383
1.348
0.0268
0.0701
˚
space group
˚
a (A)
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
3
˚
V (A )
Z
F
calcd (Mg m-3
)
μ (mm-1
R1a
)
0.098
0.093
0.0266
0.0711
0.0342
0.0852
P
wR2b
P
P
P
a R1 =
Fo|-|Fc
/
|Fo| for reflections with I > 2σ(I). b wR2 = [ [w(Fo2 - Fc2)2]/ [w(Fo2)2]0.5 for all reflections; w-1 = σ2(F2) þ (aP)2 þ bP,
where P = (2Fc þ Fo2)/3 and a and b are constants set by the program.
2
XyNCcþi), 127.5 (CH, Ar), 124.5 (CH, XyNCi), 60.9 (CH2,
tmeda), 49.5 (Me, tmeda), 41.4 (CH2, acetamide), 26.1 (NMe,
acetamide), 19.8 (Me, XyNCi), 18.6 (Me, XyNCc); CtN and i-C
of XyNCc and o-C of XyNCi not observed.
14a (free with SADI); ordered methyl groups, rigid; all others,
riding. Special features of refinement: 1b0: The Flack parameter is
t
0.001(14). One Bu group is disordered over two positions. 2b0:
The triflate anion is disordered over two positions. An ill-defined
region of residual electron density was tentatively interpreted as a
disordered acetone. Its hydrogen atoms were not included in the
refinement. 4b0: One tBu group is disordered over two positions. 9:
In the absence of significant anomalous scattering, Friedel oppo-
site reflections were merged and the Flack parameter is thus
meaningless. 10b0: A region of residual electron density could
not be interpreted in terms of realistic solvent molecules, even
allowing for possible disorder. For this reason the program
SQUEEZE (A. L. Spek, University of Utrecht, Netherlands)
was employed to remove mathematically the effects of the solvent.
Standard deviations of refined parameters should be interpreted
X-ray Structure Determinations. Crystals suitable for X-ray
diffraction studies were obtained by liquid-liquid diffusion from
CH2Cl2/n-hexane: 1b0, 3b0, 4b0 0.5CH2Cl2; CH2Cl2/n-pentane:
3
6b0, 10b0, 13b CH2Cl2, 14a; acetone/Et2O: 2b0 Me2CO; CDCl3/
3
3
n-pentane: 5b0; CH2Cl2/Et2O: 9, 15c, or by sublimation at low
pressure: 8b, 11b. Numerical details are presented in Tables 1-3.
The data for 1b0, 2b0, 4b0, 10b0, 11b, and 13b0 were collected on a
Bruker Smart APEX CCD diffractometer using monochromated
Mo KR radiation in ω-scan mode. The data for 6b0 were collected
on an Oxford Diffraction Nova O diffractometer using mirror-
focusedCuKR radiation inω-scan mode. The data for 3b0, 5b0, 8b,
9, 14a, and15c werecollected on anOxford DiffractionXcalibur S
diffractometer using monochromated Mo KR radiation in ω-scan
mode. The structures were solved by direct methods and refined
anisotropically on F2 using the program SHELXL-97 (G. M.
3
˚
with caution. The void volume per cell was 1021 A , with a void
electron count per cell of 240. This solvent was not taken into
account when calculating derived parameters such as the formula
weight, because the nature of the solvent was uncertain.
Sheldrick, UniversityofGottingen).31 Restraintstolocalaromatic
€
Results and Discussion
ring symmetry or light-atom displacement factor components
were applied in some cases. Treatment of hydrogen atoms is as
follows: NH free except for 1b0, 2b0, 6b0, 10b0 (free with DFIX) and
Syntheses of Ortho-Palladated Phenylacetamides and Cy-
clometalated Derivatives. Aryl derivatives of the type [Pd-
{C6H4CH2C(O)NRR0-2}}I(N∧N)] (N∧N=tmeda, NRR0=NH2
(31) Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, 64, 112.

Article
Organometallics, Vol. 30, No. 5, 2011 1085
Table 3. Crystallographic Data for 11b, 13b CH2Cl2, 14a, and 15c
3
11b
13b CH2Cl2
3
14a
15c
formula
fw
T (K)
λ (A)
cryst syst
C
278.34
100(2)
0.71073
monoclinic
P21/n
13.0014(12)
7.8134(7)
15.2139(14)
90
111.926(2)
90
1433.7(2)
4
1.290
0.081
0.0599
0.1265
18H18N2O
C37H39Cl2IN4OPd
859.92
100(2)
0.71073
monoclinic
P21/c
19.2766(8)
8.5432(6)
23.3527(9)
90
110.859(2)
90
3593.8(3)
4
1.589
1.559
0.0266
0.0633
C36H36F3IN4O4PdS
911.05
100(2)
0.71073
triclinic
P1
8.3013(3)
14.7697(4)
16.4066(4)
87.250(3)
75.566(4)
76.134(4)
1891.16(10)
2
C35H46F3N5O4PdS
796.23
100(2)
0.71073
monoclinic
P21/c
10.6738(2)
14.8048(3)
22.7526(4)
90
92.482(3)
90
3592.07(12)
4
1.472
0.635
0.0239
0.0454
˚
space group
˚
a (A)
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
3
˚
V (A )
Z
F
calcd (Mg m-3
)
1.600
1.419
0.0278
0.0728
μ (mm-1
R1a
)
wR2b
P
P
P
P
a R1 =
Fo|-|Fc
/
|Fo| for reflections with I > 2σ(I). b wR2 = [ [w(Fo2 - Fc2)2]/ [w(Fo2)2]0.5 for all reflections; w-1 = σ2(F2) þ (aP)2 þ bP,
2
where P = (2Fc þ Fo2)/3 and a and b are constants set by the program.
(1a), NHMe (1b), NMe2 (1c); N∧N=dbbpy, NRR0=NHMe
(1b0); Scheme 1) were synthesized by oxidative addition of
the corresponding 2-(2-iodophenyl)acetamides to “Pd-
Scheme 1
(dba)2” ([Pd2(dba)3] dba; dba = dibenzylideneacetone) in
3
the presence of tmeda or dbbpy. The reactions took place at
room temperature in toluene, THF, or CH2Cl2, and the
products were isolated in yields over 60%.
The reactions of complexes 1 with 1 equiv of AgOTf led to
the precipitation of AgI and the formation of the corresponding
cationic cyclopalladated derivatives [Pd{κ2C,O-C6H4CH2C-
(O)NRR0-2}(N∧N)]OTf (N∧N = tmeda, NRR0 = NH2
(2a), NHMe (2b), NMe2 (2c); N∧N =dbbpy, NRR0 = NHMe
(2b0)), which were isolated in high yields. In these complexes,
the amide function is coordinated to the metal through the
oxygen atom, as revealed by the IR and NMR spectra and the
crystal structure of 2b0 (see below). The reaction of 2b0 with 1
equiv of PPh3 led to the splitting of the Pd-O bond to give the
phosphino complex [Pd{C6H4CH2C(O)NHMe-2}(dbbpy)-
(PPh3)]OTf (3b0) in 69% yield.
Deprotonation of the amide function in complex 1a, 1b, or
1b0 with KOtBu in HOtBu led to the neutral cyclopalladated
derivatives [Pd{κ2C,N-C6H4CH2C(O)NR-2}(N∧N)] (N∧N =
tmeda, R = H (4a), Me (4b); N∧N = dbbpy, R = Me (4b0)),
which result from the displacement of the iodo ligand by the
nitrogen of the anionic amidate group and were isolated in
moderate to good yields. When NEt3 was used instead,
deprotonation of the amide occurred only to a small extent,
as detected by NMR. A significantly higher amount of the
amidate complexes 4 (around 33%) was detected by NMR
after treatment of the cationic complexes 2a, 2b, or 2b0 with
excess NEt3 in acetone.
In order to explore their basic character and usefulness for
the preparation of other derivatives, we studied the reactivity
of 4a and 4b0 toward the methylene-active compounds mal-
ononitrile, acetylacetone, methyl cyanoacetate, and dimeth-
yl malonate. However, only the most acidic of these reagents,
malononitrile,32 reacted to give the expected derivatives [Pd-
{C6H4CH2C(O)NHR-2}{CH(CN)2}(N∧N)] (N∧N = tmeda,
R = H (5a); N∧N = dbbpy and R = Me (5b0)); whereas 5b0
was obtained using 1 equiv of malononitrile, the formation
of 5a required an excess of this reagent and the complex
could not be isolated in pure form, probably because of
the lower basicity of the C(O)NH group as compared to
C(O)NMe.
Reactions with CO and Decomposition of the Resulting Acyl
Complexes. The reactions of complexes 1 with CO in CH2Cl2
at -17 °C afforded the insertion products [Pd{C(O)C6H4-
CH2C(O)NRR0-2}I(N∧N)] (N∧N = tmeda, NRR0 = NH2
(6a), NHMe (6b), NMe2 (6c); N∧N = dbbpy, NRR0 =
NHMe (6b0)), which were isolated in high yields (Scheme 2).
The isolation of these compounds in pure form required low
temperature because they slowly lose CO in solution at room
temperature to give the parent arylpalladium compounds.
Moreover, the tmeda complexes 6a-c gradually decom-
posed when kept in solution under CO at room or higher
(32) Bordwell, F. G. Acc. Chem. Res. 1988, 21, 456.

1086 Organometallics, Vol. 30, No. 5, 2011
Vicente et al.
Scheme 2
Scheme 3
temperatures (Scheme 2). Complete decomposition of 6a was
observed after 30 h of reaction of 1a with CO (1.4 bar) at
50 °C in CDCl3 to give quantitatively colloidal palladium,
(tmedaH)I,33 and isoquinoline-1,3(2H,4H)-dione (7a) (homo-
phthalimide),28,29,34 resulting from the reductive C-N cou-
pling. Decomposition of 6b, formed in situ from 1b under CO,
was considerably slower and reached only 71% after 3 days
(1.4 bar, 50 °C), giving an approximately 1:2 mixture of
2-methylisoquinoline-1,3(2H,4H)-dione30 (7b) and the new
isocoumarin derivative 3-(methylamino)-1H-2-benzopyran-
1-one (8b), resulting from C-N and C-O couplings, respec-
tively. Complex 6c also decomposed under CO (1.4 bar, 3 days,
50 °C), giving via a C-O coupling exclusively the new
compound 3-(dimethylamino)-1H-2-benzopyran-1-one (8c),
which was isolated in 93% yield.
A possible reaction pathway for the C-N and/or C-O
coupling processes from the tmeda derivatives 6a-c is out-
lined in Scheme 3. We assume that an equilibrium is estab-
lished between 6 and the intermediate complex A, in which
the tmeda ligand is monocoordinated and the acetamide
group is O-coordinated, increasing the acidities of both the
NH (if present) and CH2 protons. The nonbonded tmeda
nitrogen might reasonably be responsible for the deprotona-
tion of the NH and/or CH2 groups, either intra- or inter-
molecularly. The different nature of the proton involved
determines in turn the nature of the corresponding deproton-
ated complex, an amidato B, similar to 4, or an aminoeno-
lato B0, which could then undergo a C-N or C-O reductive
coupling, respectively. While for 6c only the C-O coupling
can take place, for 6a and 6b both the C-N and C-O
coupling products are possible and the relative proportions
in which they are obtained are expected to be determined by
the relative concentrations of intermediates B and B0, largely
dictated by the relative acidities of NH and CH2 protons, as
well as by the rates of the reductive coupling steps. According
to literature data,32,35 NH protons are somewhat more acidic
than R-CH protons in amides, but in the case of the NHMe
derivative the difference between the acidities of these two
types of protons will be diminished because of the electron-
donating methyl group. Therefore, in the case of 6a, the
deprotonation and coupling steps lead to 7a because of the
higher concentration of the corresponding amidate B and/or
the more rapid C-N coupling compared to the C-O cou-
pling. For 6b, the deprotonation of the methylene group
competes with that of the NHMe group, giving a 1:2 mixture
of 7b and 8b, perhaps because the steric repulsion of the
methyl substituent makes the C-N coupling slower than the
C-O coupling. Correspondingly, the slower decomposition
of 6b than of 6a (see above) can be caused by the slower C-N
coupling in the amidate B corresponding to 6b than that in
the unsubstituted analogue 6a. We note that a similar reason-
ing has been used to explain the general observation that
palladium-catalyzed intermolecular amidations of aryl ha-
lides are much slower when acyclic secondary amides are
used instead of primary amides.5
In contrast to the tmeda derivative 6b, the dbbpy complex
6b0 gave only traces of 7b and 8b after 30 h under CO (1.4 bar)
at 50 °C. The stability of 6b0 can be attributed to the better
coordination ability and lower basicity of the dbbpy ligand,
which hinders its participation as a base in the process. When
the reaction of 1b0 with CO was carried out in the presence of
NEt3, the reductive coupling did take place to an appreciable
extent, although it was rather slow (49% after 48 h at 50 °C)
and gave exclusively the isoquinolinedione 7b; as mentioned
above, NEt3 deprotonates complex 1b0 to give, to a small
extent, only amidate complex 4b0, which would react with
CO to give solely the C-N coupling product.
(33) Chitsaz, S.; Breyhan, T.; Pauls, J.; Neumuller, B. Z. Anorg. Allg.
Chem. 2002, 628, 956.
(34) Barnard, I. F.; Elvidge, J. A. J. Chem. Soc., Perkin Trans. 1 1983,
1813.
(35) Bordwell, F. G.; Fried, H. E. J. Org. Chem. 1991, 56, 4218.

Article
Organometallics, Vol. 30, No. 5, 2011 1087
Scheme 4
The reaction of the cationic cyclometalated tmeda com-
of the Pd-N bonds relative to 1a-c, it is likely that the
deprotonation step does not involve the participation of the
tmeda ligand and it is carried out by the acetone used as solvent
(Scheme 4).
plex 2a, 2b, or 2c with CO (1.4 bar, 3 h at room temperature
in acetone) led to the formation of colloidal Pd and solutions
containing 7a (100% yield), 7b þ 8b (82% total yield; 0.4:1
molar ratio), or 8c (92% yield), respectively, at a much faster
rate than their parent iodocomplexes 1a-c (Scheme 4). This
is a new example of a well-known behavior: the rates of
migratory insertions or catalytic reactions involving some
such processes are enhanced when they involve cationic
species and a coordination position is easily accessible to
the molecule to be inserted.36 At a preparative scale, com-
pound 7a was isolated in 51% yield, while by extracting an
Et2O solution of the mixture of 7b and 8b with aqueous
K2CO3, compound 8b was isolated in 59% yield. In order to
avoid the formation of 8b and thus isolate 7b, we carried out
the reaction of 2b with CO in the presence of NEt3, which
gave exclusively 7b (67% yield); as previously noted for the
reaction of 1b0 with CO, this result is explained by the
formation of the amidate 4b, which then reacts with CO to
give the C-N coupling product. The formation of the
organic products from the reactions of 2a-c with CO must
involve amidate and aminoenolate intermediates similar to
those proposed for the reactions of the iodo complexes 1a-c
with CO. However, given the higher acidity of the acetamide
protons in the cationic complexes 2a-c and the strengthening
We have found that the dbbpy complex 2b0 shows a
different behavior toward CO than do 2a-c. Thus, 2b0
reacted with CO (1.4 bar) in acetone at room temperature
to give the isochroman-1-one derivative N,3,3-trimethyl-
1-oxo-3,4-dihydro-1H-2-benzopyrane-4-carboxamide (9),
along with colloidal palladium and (dbbpyH)OTf, in a process
that involves the participation of the solvent. A possible
reactionpathwayfortheformationof9isoutlinedinScheme4.
The better coordination ability of dbbpy relative to tmeda may
stabilize the aminoenolate intermediate C, making the reduc-
tive C-O coupling more difficult and favoring the reaction
with a protonated acetone molecule to give D. This step is
related to the previously reported reactions of N,N-disubsti-
tuted 3-amino-1H-2-benzopyran-1-ones with aldehydes to
give 3,4-dihydro-1H-2-benzopyrane-4-carboxamides analo-
gous to 9,37 although these require more energetic conditions,
such as refluxing of the reagents in acetic acid, ethanol, or
acetonitrile. Next, the deprotonation of D would afford the
alcoholato complex E and, finally, compound 9 would result
from a C-O reductive coupling.
The neutral amidate complexes 4a and 4b or 4b0 also
reacted rapidly with CO at room temperature in acetone to
give Pd(0) and high yields of 7a and 7b, respectively, which
result from a C-N coupling, probably occurring through an
intermediate such as F (Scheme 4). This fact additionally
(36) Dekker, G.; Elsevier, C. J.; Vrieze, K.; van Leeuwen, P. W. N. M.
Organometallics 1992, 11, 1598. Ozawa, F.; Hayashi, T.; Koide, H.;
Yamamoto, A. J. Chem. Soc., Chem. Commun. 1991, 1469. Yamamoto,
A. J. Organomet. Chem. 1995, 500, 337. Rix, F. C.; Brookhart, M.;
White, P. S. J. Am. Chem. Soc. 1996, 118, 4746. Kayaki, Y.; Tsukamoto,
H.; Kaneko, M.; Shimizu, I.; Yamamoto, A.; Tachikawa, M.; Nakajima, T.
J. Organomet. Chem. 2001, 622, 199.
(37) Boyd, G. V.; Monteil, R. L.; Lindley, P. F.; Mahmoud, M. M. J.
Chem. Soc., Perkin Trans. 1 1978, 1351.

1088 Organometallics, Vol. 30, No. 5, 2011
Vicente et al.
suggests that, in solution, the amidates are not in equilibri-
um, at least to an appreciable extent, with their isomeric
aminoenolates.
Reactions with XyNC. The reaction of the dbbpy complex
1b0 with 1 equiv of XyNC (Xy = 2,6-dimethylphenyl) gave
the insertion product [Pd{C(dNXy)C6H4CH2C(O)NHMe-
2}I(dbbpy)] (10b0) (Scheme 5). However, the analogous
iminoacyl derivatives could not be isolated when starting
from the tmeda derivatives 1a and 1b because they immedi-
ately started to decompose, even at low temperature, giving
colloidal Pd, (tmedaH)I, and the C-N coupling products
1-(2,6-dimethylphenylimino)-1,2-dihydroisoquinolin-3(4H)-
one (11a) or 1-(2,6-dimethylphenylimino)-2-methyl-1,2-dihy-
droisoquinolin-3(4H)-one (11b), respectively. As observed for
the previous C-N couplings, the decomposition is much
faster for the unsubstituted derivative 1a (30 min at room
temperature) than for its methyl-substituted analogue 1b,
the latter requiring harsher reaction conditions (3 h at
61 °C). Compounds 11 are new members of the small family
of imino derivatives of isoquinoline-1,3(2H,4H)-dione.34,38
The reaction of 1c with 1 equiv of XyNC gave a mixture
containing a new organometallic derivative, probably the
expected insertion product, and unreacted starting materi-
al, which could not be separated. However, heating this
mixture at 60 °C for 24 h led to its gradual decomposition to
give colloidal Pd, (tmedaH)I, and an almost quantitative
yield of the new iminoisocoumarin derivative 1-(2,6-dimethyl-
phenylimino)-3-(N,N-dimethylamino)-1H-2-benzopyran
(12c), resulting from a C-O coupling. Although the for-
mation of these organic products probably takes place
through reaction pathways analogous to that proposed
for the reactions of 1a-c with CO, the experimental data
clearly show that, for 1a and 1b, the C-N couplings are
much faster than in the reactions with CO, and also than the
C-O couplings. This would explain the isolation of only
one iminoacyl complex and the absence of C-O coupling
products in these reactions with XyNC.
Scheme 5
The reactions of 1a or 1b0 with 3 equiv of XyNC gave
trans-[Pd{C(dNXy)C6H4CH2C(O)NHR-2}I(CNXy)2] (R =
H (13a), Me (13b)), which result from the displacement of the
chelating ligands by two of the isocyanide molecules and the
insertion of a third isocyanide into the Pd-C bond. The
occupancy of both positions cis to the iminoacyl ligand
prevents the coordination of the acetamide group and conse-
quently rules out any coupling process such as that observed
in the equimolecular reaction (see above and Scheme 5). The
0
˚
Figure 1. Thermal ellipsoid plot (50% probability) and crystal packing of complex 1b . Selected bond distances (A) and angles (deg):
Pd(1)-C(2) 1.986(3), Pd(1)-N(1) 2.128(2), Pd(1)-N(2) 2.0735(19), Pd(1)-I(1) 2.5671(2); C(2)-Pd(1)-N(2) 94.02(9); C(2)-Pd-
(1)-N(1) 172.50(9), N(2)-Pd(1)-N(1) 78.63(8), C(2)-Pd(1)-I(1) 88.66(8), N(2)-Pd(1)-I(1) 177.33(6), N(1)-Pd(1)-I(1) 98.69(6),
C(1)-C(2)-Pd(1) 123.40(19), C(3)-C(2)-Pd(1) 118.16(19).

Article
Organometallics, Vol. 30, No. 5, 2011 1089
reaction of 13a with 1 equiv of triflic acid led to the proton-
ation of the iminoacyl nitrogen to give trans-[Pd{C(dNHXy)-
C6H4CH2C(O)NH2-2}I(CNXy)2]OTf (14a), formally con-
taining an N-stabilized carbene ligand.
of the NHMe and NMe2 derivatives 2b, 2c, and 2b0 with
2 equiv of XyNC produced the insertion of one XyNC into
the Pd-C bond and the displacement of the O-coordinated
amide group by a second XyNC (Scheme 5)∧ to give
[Pd{C(dNXy)C6H4CH2C(O)NRR0-2}(CNXy)(N N)]OTf
(N∧N = tmeda, NRR0 = NHMe (15b), NMe2 (15c);
N∧N = dbbpy, NRR0 = NHMe (15b0)). The use of only 1
equiv of isocyanide led to the same compounds, but half of the
unreacted starting materials were recovered. The formation of
organic products is probably hindered because the C-N
and/or C-O coupling processes are more difficult than
the C-N coupling from the primary acetamide in 2a, and
The reactions of the cationic complexes 2 with XyNC were
attempted in order to explore the possible formation of
coupling products. In the case of the NH2 derivative 2a,
the 1:1 reaction led to the formation of a new complex that
could not be conveniently characterized because of its in-
stability, while the 1:2 reaction led to the formation of the
C-N coupling product 11a almost quantitatively. Probably,
the unstable compound from the 1:1 reaction is an insertion
product and the second equivalent of XyNC favors the C-N
coupling by displacing one of the N atoms of the tmeda
ligand, which can then act as a base. In contrast, the reactions
Figure 4. Thermal ellipsoid plot (50% probability) of one of the
two independent molecules of the structure of complex 4b0.
˚
Figure 2. Thermal ellipsoid plot (50% probability) of complex
Selected bond distances (A) and angles (deg): Pd(1)-C(1)
0
˚
3b . Selected bond distances (A) and angles (deg): Pd-C(1)
1.9906(14), Pd-N(11) 2.1070(11), Pd-N(21) 2.1749(12), Pd-P
2.2643(4), C(1)-C(2) 1.399(2), C(1)-C(6) 140.1(2); C(1)-
Pd-N(11) 90.68(5), C(1)-Pd-N(21) 166.96(5), N(11)-Pd-N-
(21) 77.00(4), C(1)-Pd-P 85.01(4), N(11)-Pd-P 174.92(3),
N(21)-Pd-P 107.07(3), C(2)-C(1)-Pd 122.99(11), C(6)-C(1)-
Pd 166.4(11).
1.983(4), Pd(1)-N(3) 2.012(3), Pd(1)-N(2) 2.049(3), Pd(1)-N-
(1) 2.111(3), N(3)-C(8) 1.319(5), N(3)-C(9) 1.465(5), C(8)-O-
(1) 1.264(5); C(1)-Pd(1)-N(3) 86.02(14), C(1)-Pd(1)-N(2)
98.02(14), N(3)-Pd(1)-N(1) 98.19(12), N(2)-Pd(1)-N(1)
77.74(12), C(8)-N(3)-C(9) 114.8(3), C(8)-N(3)-Pd(1) 123.7(3),
C(9)-N(3)-Pd(1) 121.5(2), O(1)-C(8)-N(3) 124.9(4), O(1)-
C(8)-C(7) 119.0(3), N(3)-C(8)-C(7) 116.1(3).
0
˚
Figure 3. Thermal ellipsoid plot (50% probability) and crystal packing of complex 2b . Selected bond distances (A) and angles (deg):
Pd(1)-C(2) 1.991(4), Pd(1)-N(2) 2.023(3), Pd(1)-O(1) 2.031(2), Pd(1)-N(1) 2.089(3), O(1)-C(8) 1.263(4), C(8)-N(3) 1.317(4),
N(3)-C(9) 1.453(4); C(2)-Pd(1)-N(2) 100.15(13), C(2)-Pd(1)-O(1) 88.74(12), N(2)-Pd(1)-N(1) 79.23(11), O(1)-Pd(1)-N(1)
91.97(10), C(8)-O(1)-Pd(1) 121.1(2), C(8)-C(7)-C(1) 110.7(3), O(1)-C(8)-N(3) 120.0(3), O(1)-C(8)-C(7) 121.7(3), N(3)-C-
(8)-C(7) 118.3(3), C(8)-N(3)-C(9) 123.1(3).

1090 Organometallics, Vol. 30, No. 5, 2011
Vicente et al.
thus the reaction sequence ends with the formation of the
stable compound 15b, 15b0, or 15c.
singlet (4a), an AB system (4b), or a very broad resonance
(4b0). The latter resolves as an AB system at 233 K (see
Experimental Section and SI for details). Therefore, the rate
of the ring flipping process follows the order 2 > 4a > 4b0 >
4b. The mutual repulsion between the H6 of dbbpy or the Me
group of tmeda with the R group of the amidate in complexes
4 and the absence of such repulsions in complexes 2 could
account for the above-mentioned differences.
The amidate complexes 4a, 4b, and 4b0 reacted only
sluggishly with XyNC. In all three cases, the main product
was the C-N coupling compound 11a or 11b, but the
reactions required heating at 60 °C in CHCl3 for 16-48 h,
and the organic compounds were obtained contaminated by
decomposition products.
Spectroscopic Features. The methylenic protons are ob-
served in the room-temperature 1H NMR spectra of the aryl
complexes 1 and 3b0 as an AB system because the aryl ligand
does not lie in the coordination plane and its rotation around
the Pd-C bond must be restricted. In the iminoacyl complex
10b0 such restriction is observed only at low temperatures
(see Experimental Section and SI for details), while the RT
spectrum shows the methylenic protons as a broad singlet.
The singlet observed for the CH2 protons in the spectra of
complexes 2 and 6 must be attributed, respectively, to a fast
ring flipping process that makes them equivalent and to the
lower steric demand of the O atom with respect to the NXy
group present in 10b0. In the cyclic amidate complexes 4 the
methylenic protons generate, at room temperature, a broad
The solid-state IR spectra of the Pd complexes that con-
tain the free acetamide group show the ν(CdO) band in the
range 1636-1687 cm-1, that is, at frequencies similar to or
slightly higher than those corresponding to 2-(2-iodophe-
nyl)acetamides (C6H4ICH2CONRR0, with NRR0 = NH2
(1659 cm-1), NHMe (1641 cm-1), NMe2 (1642 cm-1)). The
cationic cyclopalladated derivatives 2 show lower energies
for this band (∼1615 cm-1) because of the coordination of
the amide function through the O atom, which must cause a
slight decrease in the C-O bond order. The even lower
energy of the ν(CdO) band found in the amidate complexes
Figure 7. Thermal ellipsoid plot (50% probability) of complex
0
˚
10b . Selected bond distances (A) and angles (deg): Pd(1)-C(10)
1.995(2), Pd(1)-N(1) 2.0928(17), Pd(1)-N(2) 2.1557(17), Pd-
(1)-I(1) 2.5753(2), N(3)-C(10) 1.285(3), N(4)-C(8) 1.330(3),
O(1)-C(8) 1.226(3); C(10)-Pd(1)-N(1) 97.37(7), N(1)-Pd-
(1)-N(2) 78.10(6), C(10)-Pd(1)-I(1) 90.25(6), N(2)-Pd(1)-I-
(1) 96.52(5), C(10)-N(3)-C(31) 122.77(17), C(8)-N(4)-C(9)
122.1(2), O(1)-C(8)-N(4) 123.1(2), O(1)-C(8)-C(7) 121.9(2),
N(4)-C(8)-C(7) 114.9(2), N(3)-C(10)-C(2) 117.88(18), N-
(3)-C(10)-Pd(1) 122.49(15), C(2)-C(10)-Pd(1) 119.61(14).
Figure 5. Thermal ellipsoid plot (50% probability) of complex
0
˚
5b . Selected bond distances (A) and angles (deg): Pd-C(1)
1.9925(13), Pd-N(21) 2.0793(11), Pd-C(31) 2.0903(13), Pd-
N(11) 2.1402(11), O-C(8) 1.2243(17), C(8)-N(1) 1.3406(19),
C(9)-N(1) 1.449(2); C(1)-Pd-N(21) 94.59(5), C(1)-Pd-
C(31) 87.06(5), N(21)-Pd-C(31) 175.99(5), C(1)-Pd-
N(11) 169.10(5), N(21)-Pd-N(11) 78.33(4), C(31)-Pd-N(11)
100.55(5), C(32)-C(31)-C(33) 111.95(12).
0
˚
Figure 6. Thermal ellipsoid plot (50% probability) and crystal packing of complex 6b . Selected bond distances (A) and angles (deg):
Pd-C(1) 1.970(4), Pd-N(11) 2.085(3), Pd-N(21) 2.168(3), Pd-I 2.5820(4), O(1)-C(1) 1.211(5), C(2)-C(3) 1.431(6), C(2)-C(7)
1.396(6); C(1)-Pd-N(11) 94.52(15), C(1)-Pd-N(21) 170.39(14), N(11)-Pd-N(21) 77.57(13), C(1)-Pd-I 88.33(11), N(11)-Pd-I
174.29(9), N(21)-Pd-I 100.04(9), O(1)-C(1)-Pd 118.3(3), O(1)-C(1)-C(2) 122.6(3), C(2)-C(1)-Pd 118.8(3).

Article
Organometallics, Vol. 30, No. 5, 2011 1091
˚
Figure 8. Thermal ellipsoid plot (50% probability) and hydrogen bonds of complex 13b. Selected bond distances (A) and angles (deg):
Pd(1)-C(11) 1.971(2), Pd(1)-C(31) 1.978(2), Pd(1)-C(21) 2.051(2), Pd(1)-I(1) 2.7037(2), C(1)-C(2) 1.417(3), C(2)-C(3) 1.402(3),
C(21)-N(3) 1.270(3), C(31)-N(1) 1.150(3), C(11)-N(2) 1.148(3), C(2)-C(21) 1.495(3); C(11)-Pd(1)-C(31) 179.05(9), C(11)-Pd-
(1)-C(21) 90.04(8), C(31)-Pd(1)-C(21) 89.93(8), C(11)-Pd(1)-I(1) 88.52(6), C(31)-Pd(1)-I(1) 91.55(6), C(21)-Pd(1)-I(1)
177.44(6), N(2)-C(11)-Pd(11) 175.91(19), N(3)-C(21)-Pd(1) 123.52(16), C(2)-C(21)-Pd(1) 115.62(15), N(1)-C(31)-Pd(1)
176.49(19).
˚
Figure 9. Thermal ellipsoid plot (50% probability) and hydrogen bonding of complex 14a. Selected bond distances (A) and angles
(deg): Pd-C(40) 1.964(2), Pd-C(30) 1.971(2), Pd-C(20) 2.025(2), Pd-I 2.6250(2), O(1)-C(2) 1.249(3), N(1)-C(2) 1.315(3),
N(2)-C(20) 1.303(3), N(2)-C(21) 1.441(3), N(3)-C(30) 1.145(3), N(3)-C(31) 1.397(3), N(4)-C(40) 1.147(3), N(4)-C(41)
1.405(3); C(40)-Pd-C(20) 91.82(8), C(30)-Pd-C(20) 89.87(9), C(40)-Pd-I 89.00(6), C(30)-Pd-I 89.48(6), C(20)-N(2)-C(21)
125.47(18), C(30)-N(3)-C(31) 174.1(2), C(40)-N(4)-C(41) 176.2(2), O(1)-C(2)-N(1) 122.4(2), O(1)-C(2)-C(1) 119.96(19),
N(1)-C(2)-C(1) 117.64(19), N(2)-C(20)-C(11) 119.94(19), N(3)-C(30)-Pd 177.7(2), N(4)-C(40)-Pd 177.24(18).
4 (∼1580 cm-1) is typical of metal complexes with this kind
of ligand8,39 and can be ascribed to the delocalization of the
negative charge over the N-CdO group, which significantly
decreases the C-O bond order.
The aromatic ring of the aryl ligand in complexes 1b0 and
3b0 (Figures 1 and 2, respectively) is almost perpendicular to
the Pd coordination mean plane, as is commonly found in
ortho-substituted arylpalladium derivatives and attributed
to the steric demand of the ortho substituent.8,10,18,22,40 This
is in agreement with the NMR data mentioned above. The
Pd-C bond distances are normal for this type of derivative.
The molecules in 1b0 are connected through three nonclassi-
Crystal Structures. The crystal structures of complexes 1b0
(Figure 1), 2b0 Me2CO (Figure 3), 3b0 (Figure 2),
3
4b0 0.5CH2Cl2 (Figure 4), 5b0 (Figure 5), 6b0 (Figure 6),
3
10b0 (Figure 7), 13b CH2Cl2 (Figure 8), 14a (Figure 9), and
3
15c (Figure 10) and the organic compounds 8b, 9, and 11b
(see Supporting Information) were determined by means of
X-ray diffraction studies. All the Pd complexes exhibit
slightly distorted square-planar environments around the
metal. The greatest distortions are caused by the small bite of
the dbbpy ligand (angles N-Pd-N around 78°).
cal hydrogen bonds C-H O, giving chains along the c axis
3 3 3
(Figure 1). The triflate anion in 3b0 is connected to the cation
through one N-H O hydrogen bond involving the acet-
3 3 3
amide moiety (Figure 2).
The structure of 2b0 (Figure 3) was solved as an acetone
monosolvate. The acetamide group is coordinated to the Pd
atom through the oxygen, forming a six-membered ring with
a pseudoboat conformation. The Pd(1)-O(1) bond distance
€
(38) Mohrle, H.; Rohn, C. Z. Naturforsch., B: Chem. Sci. 2007, 62,
249.
(39) Yamamoto, T.; Sano, K.; Osakada, K.; Komiya, S.; Yamamoto,
A.; Kushi, Y.; Tada, T. Organometallics 1990, 9, 2396.
ꢀ
(40) Vicente, J.; Abad, J. A.; Fernandez-de-Bobadilla, R.; Jones,
P. G.; Ramırez de Arellano, M. C. Organometallics 1996, 15, 24.

1092 Organometallics, Vol. 30, No. 5, 2011
Vicente et al.
As observed for 1b0 and 3b0, the aromatic ring of the
aryl ligand in 5b0 is practically perpendicular to the Pd
coordination mean plane. The acetamide group is connected
through an N-H N hydrogen bond to one of the CN
3 3 3
groups of a neighboring molecule, forming inversion-sym-
metric dimers.
The benzoyl ligand in complex 6b0 (Figure 6) is practically
˚
planar (mean deviation 0.024 A, excluding the acetamide
group), and its mean plane forms an angle of 91.8° with the
mean plane of atoms Pd-I-N(11)-N(21)-C(1) (mean
˚
deviation 0.085 A). The Pd-C bond distance is normal for
this type of compound.10,14,19 The acetamide groups of
adjacent molecules are connected through N-H OdC
3 3 3
hydrogen bonds, thus forming infinite chains (Figure 6).
Unlike the benzoyl group in 6b0, the iminoacyl group in
10b0 (excluding the acetamide group) is not planar (Figure 7).
Thus, the mean plane of the aromatic ring (atoms C(1-6),
˚
mean deviation 0.016 A) is rotated by 46.2° with respect to
Figure 10. Thermal ellipsoid plot (50% probability) of complex
˚
the C2-C10-N3 plane. In turn, the latter substends an angle
of 72.2° to the mean Pd coordination plane (Pd-I-N(1)-
N(2)-C(10), mean deviation, 0.191 A). The particular con-
15c. Selected bond distances (A) and angles (deg): Pd-C(30)
1.9253(18), Pd-C(10) 2.0327(16), Pd-N(5) 2.1625(14), Pd-N-
(4) 2.2029(13), O(1)-C(2) 1.225(2), N(1)-C(2) 1.352(2), N-
(2)-C(10) 1.266(2), N(3)-C(30) 1.154(2); C(30)-Pd-C(10)
84.73(7), C(10)-Pd-N(5) 97.61(6), C(30)-Pd-N(4) 95.17(6),
N(5)-Pd-N(4) 83.10(5), N(3)-C(30)-Pd 177.73(15), N-
(2)-C(10)-C(11) 119.42(14), C(10)-N(2)-C(21) 127.90(14).
˚
formation of the iminoacyl ligand appears to originate from
the formation of an intramolecular hydrogen bond between
the NH group and the iminoacyl N atom. The Pd(1)-C(10)
˚
bond distance of 1.995(2) A and the arrangement of the
iminoacyl ligand are similar to those found in [Pd-
{C(dNXy)C6H4OC(O)Me-2}I(bpy)].19
˚
of 2.031(2) A is similar to that found for the ortho-palladated
arylurea [Pd{κ2C,O-C6H4NHC(O)NHTo-2}(tmeda)]OTf15
The structure of complex 13b (Figure 8) was solved as a
CH2Cl2 monosolvate. The arrangement and conformation
of the iminoacyl ligand are very similar to those found in
and several O-coordinated amides.41 The C(8)-O(1) bond
distance of 1.263(4) A is slightly longer than the correspond-
˚
ing distance in the free acetamide group of complex 1b0
10b0, including the intramolecular N-H N hydrogen
3 3 3
˚
(1.227(3) A), because of the coordination to palladium
through the oxygen atom. Consequently, the C(8)-N(3)
bond distance of 1.317(4) A is shorter than that found for
˚
1b (1.333(4) A). The triflate anion in 2b is connected to the
cation through one N-H O hydrogen bond, giving dou-
ble chains parallel to the b axis (Figure 3).
˚
bond. The Pd(1)-C(21) bond distance of 2.051(2) A is
similar to that found for [Pd{C(dNXy)C6H4OC(O)Me-2I-
˚
(CNXy)2].19 The molecules are connected through nonclas-
0
0
sical hydrogen bonds C-H O, giving dimers.
3 3 3
3 3 3
The coordination environment around the palladium atom
in complex 14a (Figure 9) is identical to that found in 13b. The
conformation and arrangement of the protonated iminoacyl
ligand resemble those found for the iminoacyl ligand in 10b0
and 13b, except that the hydrogen bond is now formed between
the NH group of the protonated iminoacyl and the oxygen of
the acetamide group. The two H atoms of the NH2 group are
involved in hydrogen bonds with two oxygen atoms of differ-
ent triflate anions, one within the asymmetric unit and one
related by inversion (Figure 9). The protonation of the imi-
noacyl N atom causes a slight lengthening of the C-N bond
Compound 4b0 (Figure 4) crystallized with two formula
units and one CH2Cl2 molecule in the asymmetric unit. The
amidate group is coordinated to the Pd atom through the
nitrogen, forming a six-membered ring with a pseudoboat
conformation. The Pd-N(3) bond distance of 2.012(3) or
2.009(3) A is typical of palladium amidate complexes.42 The
˚
˚
C(8)-O(1) bond length of 1.264(5) or 1.257(5) A is slightly
longer than the corresponding distance in the free acetamide
group of complex 1b0, consistent with a significant delocali-
zation of the negative charge over the N-CdO group.
The structure of 5b0 shows the malononitrilato ligand
bonded to the Pd atom through the central carbon (Figure 5).
Prior to this work, only two crystal structures of Pd complexes
containing this ligand had been reported, namely, [Pd(C6F5)-
˚
˚
distance (1.303(3) A) as compared to 13b (1.270(3) A), which
reflects a decrease in the C-N bond order, while the Pd(1)-C-
(20) bond distance of 2.025(2) A is slightly shorter than that
˚
˚
found for 13b (2.051(2) A). These data suggest some degree of
carbene character for the Pd-C bond.
{CH(CN)2}(tmeda)]43 and [{Pd(C6F5)2{μ-CH(CN)2}}2]2- 44
.
The arrangement of the iminoacyl ligand in 15c (Figure 10)
is similar to that found for 10b0 and 13b, except that there is
no intramolecular hydrogen bonding. Analogous structures
have been found for [Pd{C(dNXy)C6H4OH-2}(CNXy)-
(41) Kiers, N. H.; Feringa, B. L.; Kooijman, H.; Spek, A. L.; van
ꢀ
Leeuwen, P. W. N. M. Chem. Commun. 1992, 1169. Sole, D.; Vallverdu,
L.; Solans, X.; Font-Bardia, M. Chem. Commun. 2005, 2738. Sole, D.;
Solans, X.; Font-Bardia, M. Dalton Trans. 2007, 4286.
(42) Liao, C.-Y.; Chan, K.-T.; Zeng, J.-Y.; Hu, C.-H.; Tu, C.-Y.; Lee,
H. M. Organometallics 2007, 26, 1692. Zaitsev, V. G.; Shabashov, D.;
ꢀ
ꢀ
(bpy)]OTf Et2O19 and [Pd{C(dNXy)C6H4NH2-2}(CNXy)-
3
(bpy)]OTf.17
€
Daugulis, O. J. Am. Chem. Soc. 2005, 127, 13154. Behrens, H.; Frohlich,
R.; Wurthwein, E.-U. Eur. J. Org. Chem. 2005, 3891. Haas, K.;
Conclusions
€
€
Ehrenstorfer-Schafers, E.-M.; Polborn, K.; Beck, W. Eur. J. Inorg.
Chem. 1999, 465.
(43) Ruiz, J.; Martınez, M. T.; Rodrıguez, V.; Lopez, G.; Perez, J.;
The present work is the first systematic study on the
reactivity of ortho-palladated phenylacetamides, which includes
the preparation of cyclometalated derivatives and their reactions
toward CO and XyNC. We have shown that intramolecular
ꢀ
Chaloner, P.; Hitchcock, P. B. Dalton Trans. 2004, 3521.
ꢀ
ꢀ
ꢀ
(44) Ruiz, J.; Rodrıguez, V.; Lopez, G.; Casabo, J.; Molins, E.;
Miratvilles, C. Organometallics 1999, 18, 1177.

Article
Organometallics, Vol. 30, No. 5, 2011 1093
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and Fundacion Seneca (04539/GERM/06) for financial
support.
ꢀ
C-N and C-O reductive couplings take place under relatively
mild conditions after the insertion of CO or XyNC into the
Pd-C bond. Depending on the substituents on the amidic
nitrogen, C-N and/or C-O couplings may occur. As far as we
are aware, the palladium-mediated C-O couplings reported
here are the first involving an amide function. A series of new
heterocyclic compounds have been obtained, including iso-
coumarins, imino derivatives of isoquinoline-1,3(2H,4H)-
dione, and one iminoisocoumarin.
Supporting Information Available: Experimental procedures
and spectroscopic and analytical data for 1b, 1c, 1b0, 2b, 2c, 2b0,
4b, 4b0, 6b, 6c, 6b0, 13b, 15c, and 15b0. Variable-temperature 1H
NMR spectra of 4b0 and 10b0. X-ray structure descriptions for
8b, 9, and 11b. Listing of all refined and calculated atomic
coordinates, anisotropic thermal parameters, bond lengths and
angles, and CIF files for 1b0, 2b0 Me2CO, 3b0, 4b0 0.5CH2Cl2,
3
3
5b0, 6b0, 8b, 9, 10b0, 11b, 13b CH2Cl2, 14a, and 15c. This material
ꢀ
Acknowledgment. We thank Ministerio de Educacion
y Ciencia (Spain), FEDER (CTQ2007-60808/BQU),
3
is available free of charge via the Internet at http://pubs.acs.org.