Organometallics
Article
C 52.32, H 5.64, N 3.80. Found: C 52.03, H 5.49, N 3.68. The pre-
sence of residual solvent was confirmed by H NMR spectrum.
In Situ NMR Study. A solution of ligand 1 (0.02 mmol, 12.2 mg in
0.8 mL of deuterated solvent) was added to solid [(LNC)Pd(OAc)]2
(0.01 mmol, 6.0 mg). The resulting mixture was stirred for 24 h in the
dark and analyzed by 1H and 31P{1H} NMR spectrometry. The
reactions in dmso-d6 (δP 28.9 major, 30.6 minor), CD3CN (δP 29.4
major, 32.7 minor), or CDCl3 (δP ca. 29.6 major, 30.1 minor; broad
signals) produced mixtures of two Pd complexes in ca. 60:40 molar
ratio. When the reaction was conducted in CD3OD, pure 9 separated
directly from the reaction mixture as a microcrystalline solid.
Reaction of [(LNC)Pd(OAc)]2 with (Diphenylphosphino)-
ferrocene. A solution of FcPPh2 (74 mg, 0.20 mmol) in THF (5 mL)
was added to solid [(LNC)Pd(OAc)]2 (60 mg, 0.10 mmol). The reaction
mixture was stirred for 1 h and evaporated, and the solid residue was dried
in vacuo. Yield: 134 mg (quant.), yellow compound.
1
Preparation of [HNEt3][(LNC)PdCl(Ph2PfcCONHCH2SO3-κP)]
(8). A solution of ligand 1 (0.10 mmol, 61 mg) in dry dichloromethane
(5 mL) was added to solid [(LNC)PdCl]2 (0.050 mmol, 27.5 mg). The
resulting solution was stirred for 1 h and then concentrated to ca. 1 mL
on a rotary evaporator. The concentrated solution was added dropwise
into boiling ethyl acetate (10 mL), and the mixture was slowly cooled
to room temperature. The separated crystalline material was isolated by
suction and dried in vacuo. Yield: 73 mg (83%), ruby red crystals.
1H NMR (CDCl3): δ 1.32 (t, 3JHH = 7.4 Hz, 9 H, CH3 of Et3NH+),
4
3
2.85 (d, JPH = 2.7 Hz, 6 H, CH3N), 2.99 (q, JHH = 7.4 Hz, 6 H,
4
CH3CH2), 4.12 (d, JPH = 2.2 Hz, 2 H, CH2NMe2), 4.46−4.51 (m,
4 H, C10H8 + CH2S), 4.63 (bs, 2 H, fc), 4.84 (br s, 2 H, fc), 4.90 (br s,
2 H, fc), 6.24 (td, J = 6.4, 1.1 Hz, 1 H, C6H4), 6.38 (td, J = 7.5, 1.3 Hz,
1 H, C6H4), 6.83 (td, J = 7.4, 1.1 Hz, 1 H, C6H4), 6.90 (unresolved t,
1 H, NH), 6.38 (dd, J = 7.4, 1.5 Hz, 1 H, C6H4), 7.30−7.44 (m, 6 H,
PPh2), 7.50−7.60 (m, 4 H, PPh2). 13C{1H} NMR (CDCl3): δ 8.70
4
1H NMR (CDCl3): δ 1.38 (s, 3 H, CH3CO2), 2.75 (d, JPH = 2.7
4
Hz, 6 H, NMe2), 4.00 (virtual q, J′ = 2.0 Hz, 2 H, fc), 4.05 (d, JPH
=
2.3 Hz, 2 H, NCH2), 4.32 (m, 2 H, fc), 4.40 (s, 5 H, fc), 6.49 (dd, J =
5.5, 1.3 Hz, 1 H, C6H4), 6.55 (td, J = 7.7, 1.6 Hz, 1 H, C6H4), 6.92 (td,
J = 7.3, 1.2 Hz, 1 H, C6H4), 7.05 (dd, J = 7.4, 1.5 Hz, 1 H, C6H4),
7.36−7.47 (m, 6 H, PPh2), 7.69 (m, 4 H, PPh2). 13C{1H} NMR
(CDCl3): δ 24.05 (CH3CO2), 49.91 (d, 3JPC = 2 Hz, NMe2), 70.21 (s,
3
(CH3 of Et3NH+), 46.19 (CH2 of Et3NH+), 50.16 (d, JPC = 2 Hz,
NCH3), 53.43, 55.72 (CH2S and CH2NMe2); 69.69, 73.62, 74.20 (CH
of fc); 74.34 (d, JPC = 7 Hz, CH of fc), 74.98 (Cipso of fc), 122.49 (CH
of C6H4), 123.77 (CH of C6H4), 124.92 (d, JPC = 5 Hz, CH of C6H4),
127.99 (d, JPC = 11 Hz, CH of PPh2), 130.82 (CH of PPh2), 131.41 (d,
1JPC = 49 Hz, Cipso of PPh2), 134.34 (d, JPC = 12 Hz, CH of PPh2),
138.39 (d, JPC = 11 Hz, CH of C6H4), 148.10 (d, JPC = 2 Hz, C-Pd of
C6H4), 152.17 (C-CH2 of C6H4), 169.58 (CO). 31P{1H} NMR
(CDCl3): δ 32.8 (s). IR (Nujol, cm−1): ν 3293 (s), 2695 (s), 1738
(m), 1650 (m), 1633 (m), 1580 (w), 1535 (s), 1305 (m), 1288 (m),
1246 (m), 1214 (m), 1174 (vs), 1098 (m), 1068 (w), 1041 (s), 996
(vw), 969 (vw), 845 (m), 814 (vw), 751 (m), 744 (m), 696 (m), 622
(m), 543 (w), 522 (m), 509 (m), 487 (vw), 471 (w), 437 (m). ESI−-
MS: m/z 783 ([(LNC)PdCl(Ph2PfcCONHCH2SO3)]−). Anal. Calcd
for C39H39N3PdClPFeO4S·0.3CH2Cl2·0.3AcOEt (936.5): C 51.94, H
5.60, N 4.49. Found: C 51.35, H 5.60, N 4.31. The amount of
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CH of fc), 71.15 (d, JPC = 7 Hz, CH of fc), 72.51 (d, JPC = 3 Hz,
NCH2), 72.72 (d, JPC = 57 Hz, C-P of fc), 74.51 (d, JPC = 10 Hz, CH
of fc), 122.76, 123.88, 124.62 (d, JPC = 5 Hz) (3× CH of C6H4);
127.84 (d, JPC = 10 Hz, CH of PPh2), 130.24 (d, 4JPC = 2 Hz, CHpara of
PPh2), 131.34 (d, 1JPC = 49 Hz, Cipso of PPh2), 134.39 (d, JPC = 12 Hz,
CH of PPh2), 138.02 (d, JPC = 10 Hz, CH of C6H4), 146.25 (d, JPC
=
5 Hz, C-Pd of C6H4), 148.63 (d, JPC = 2 Hz, C-CH2 of C6H4), 176.92
(CH3CO2). 31P{1H} NMR (CDCl3): δ 29.6 (s). ESI+-MS: m/z 692
([M + Na]+), 611 ([(LNC)Pd(FcPPh2) + H]+).
Pd-Catalyzed Cyanation of Aryl Bromides. A General
Procedure. A reaction vessel was charged with aryl bromide (1.0
mmol), potassium carbonate (138 mg, 1.0 mmol), potassium hexa-
cyanoferrate(II) trihydrate (212 mg, 0.5 mmol), and a palladium
source (2 mol % with respect to the aryl bromide). The flask was
equipped with a magnetic stirring bar, flushed with argon, and sealed.
The solvent (1,4-dioxane/water, 1:1; 4 mL) was added via syringe, and
the sealed flask was transferred into an oil bath maintained at 100 °C.
After stirring for 18 h, the reaction mixture was cooled and quenched
with water (2 mL), ethyl acetate (5 mL), and mesitylene (120 mg,
1.0 mmol) as an internal standard. After the organic layer was analyzed
by NMR spectroscopy, it was separated and washed with brine
(10 mL). The aqueous layer was extracted with ethyl acetate (3×
5 mL). The organic extracts were combined, dried over magnesium
sulfate, and evaporated under reduced pressure. The crude product
was purified by flash column chromatography over silica using an ethyl
acetate/hexanes mixture to give pure nitriles after evaporation.
Carboxylic acids 11k and 11l were isolated similarly after acidification
of the reaction mixture with 3 M HCl.
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clathrated solvents was corroborated by H NMR spectroscopy.
Preparation of [(LNC)Pd(Ph2PfcCONHCH2SO3-κ2P,O)] (9).
Ligand 1 (0.10 mmol, 61 mg) was dissolved in chloroform (3 mL),
and the solution was added to a solution of [(LNC)Pd(OAc)]2 (0.050
mol, 28 mg) in the same solvent (2 mL). The resulting mixture was
stirred for 24 h and concentrated to ca. 1 mL. The solution was filtered
through a pad of Celite, and the filtrate containing 9 and 9a was
carefully layered with diethyl ether. Subsequent crystallization by
liquid-phase diffusion over several days gave a crystalline material,
which was filtered off, washed with diethyl ether, and carefully dried to
afford analytically pure 9. Yield: 43 mg (58%), orange crystals.
1H NMR (CDCl3): δ 2.84 (d, 4JPH = 2.5 Hz, 6 H, CH3N), 3.98 (vq,
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J′ = 2.0 Hz, 2 H, fc), 4.09 (br s, 2 H, fc), 4.44 (d, JHH = 6.5 Hz, 2 H,
CH2S), 4.50 (vt, J′ = 2.0 Hz, 2 H, fc), 4.56 (br s, 2 H, fc), 5.69 (s, 2 H,
CH2NMe2), 6.26 (t, J = 6.7 Hz, 1 H, C6H4), 6.36 (dt, J = 7.6, 1.2 Hz, 1
H, C6H4), 6.83 (dt, J = 7.2, 0.6 Hz, 1 H, C6H4), 6.96 (dd, J = 7.5, 1.5
Hz, 1 H, C6H4), 7.34−7.47 (m, 6 H, PPh2), 7.67−7.76 (m, 4 H, PPh2),
9.09 (t, 3JHH = 6.5 Hz, 1 H, NH). 13C{1H} NMR (CDCl3): δ 49.88 (d,
3JPC = 2 Hz, NCH3), 56.34 (CH2S), 72.10 (d, 3JPC = 4 Hz, CH2NMe2),
Characterization Data. 4-Cyanoanisole (11a): 1H NMR (CDCl3):
δ 3.86 (s, 3 H, CH3O), 6.96 (dm, 3JHH = 6.8 Hz, 2 H, C6H4), 7.59 (dm,
3JHH = 7.0 Hz, 2 H, C6H4) (ref 36). 4-Cyanotoluene (11b): 1H NMR
3
(CDCl3): δ 2.42 (s, 3 H, CH3), 7.27 (dm, JHH = 7.9 Hz, 2 H, C6H4),
7.54 (dm, 3JHH = 8.1 Hz, 2 H, C6H4) (ref 36). 3-Cyanotoluene (11c):
1H NMR (CDCl3): δ 2.34 (s, 3 H, CH3), 7.32−7.49 (m, 4 H, C6H4)
1
72.19 (d, JPC = 57 Hz, C-P of fc), 72.87, 73.35 (unresolved d) and
73.40 (CH of fc); 74.98 (C-CONH of fc), 76.37 (d, JPC = 10 Hz, CH
of fc), 122.76 (CH of C6H4), 124.58 (CH of C6H4), 125.40 (d, JPC = 5
1
(ref 37). 2-Cyanotoluene (11d): H NMR (CDCl3): δ 2.55 (s, 3 H,
CH3), 7.27 (tm, 3JHH = 8.2 Hz, 1 H, H5 of C6H4), 7.32 (dm, 2JHH = 7.3
Hz, 1 H, H6 of C6H4), 7.48 (td, 3JHH = 7.6 Hz, 4JHH = 1.4 Hz, 1 H, H4 of
C6H4), 7.60 (dd, 3JHH = 8.2 Hz, 4JHH = 1.4 Hz, 1 H, H3 of C6H4) (ref 36).
3
Hz, CH of C6H4), 128.64 (d, JPC = 11 Hz, CHmeta of PPh2), 129.96
1
4
(d, JPC = 49 Hz, Cipso of PPh2), 131.34 (d, JPC = 2 Hz, CHpara of
PPh2), 128.20 (d, 2JPC = 13 Hz, CHortho of PPh2), 138.65 (d, JPC = 13
Hz, CH of C6H4), 143.23 (d, JPC = 4 Hz, Cipso of C6H4), 148.21 (d,
JPC = 2 Hz, Cipso of C6H4), 173.07 (CO). 31P{1H} NMR (CDCl3):
δ 30.4 (s). IR (Nujol, cm−1): ν 3238 (s), 1588 (m), 1578 (vs), 1556
(vs), 1402 (m), 1338 (w), 1323 (m), 1294 (vw), 1250 (m), 1214 (s),
1195 (vw), 1180 (vs), 1157 (vw), 1095 (m), 1072 (vw), 1037 (vs),
1002 (w), 978 (vw), 964 (vw), 898 (w), 870 (w), 845 (w), 830 (vw),
752 (m), 746 (m), 706 (w), 697 (m), 630 (m), 596 (m), 540 (w), 518
(m), 491 (m), 479 (m), 456 (vw), 445 (m), 440 (w). ESI+-MS: m/z
769 ([(LNC)Pd(Ph2PfcCONHCH2SO3) + Na]+), 747 ([(LNC)Pd-
(Ph2PfcCONHCH2SO3) + H]+). Anal. Calcd for C33H33O4PFeN2S
(746.9): C 53.06, H 4.45, N 3.75. Found: C 52.69, H 4.57, N 3.57.
1
4-tert-Butylbenzonitrile (11e): H NMR (CDCl3): δ 1.33 (s, 9 H,
CH3), 7.48 (dm, 3JHH = 8.8 Hz, 2 H, C6H4), 7.59 (dm, 3JHH = 8.8 Hz,
2 H, C6H4) (ref 38). 4-(Trifluoromethyl)benzonitrile (11f): 1H
NMR (DMSO-d6): δ 7.84 (d, 3JHH = 7.7 Hz, 2 H, C6H4), 8.06 (d, 3JHH
=
7.9 Hz, 2 H, C6H4). Spectra recorded in CDCl3 corresponded with the
literature data (ref 36). 4-Cyanoacetophenone (11g): 1H NMR
(CDCl3): δ 2.65 (s, 3 H, CH3), 7.78 (dm, 3JHH = 8.0 Hz, 2 H, C6H4),
8.05 (dm, 3JHH = 8.1 Hz, 2 H, C6H4) (ref 39). 4-Cyanobiphenyl (11h):
1H NMR (CDCl3): δ 7.42−7.51 (m, 3 H, C12H9), 7.57−7.61 (m, 2 H,
C12H9), 7.66−7.74 (m, 4 H, C12H9) (ref 38). 4-Chlorobenzonitrile
1
3
(11i): H NMR (CDCl3): δ 7.47 (dm, JHH = 8.8 Hz, 2 H, C6H4),
736
dx.doi.org/10.1021/om2011529 | Organometallics 2012, 31, 729−738