2248 Bull. Chem. Soc. Jpn., 77, No. 12 (2004)
Selective Oxidative Carbonylation of Amines
(18H, P(CH3)3, vt, 2JPH ¼ 3:7 Hz), 1.23 (3H, CH2CH3, t, 2JHH
¼
situ, and their structures were confirmed in solutions by NMR, ex-
cept for the acetone-coordinated carbamoylpalladium complex 4a.
Preparation of trans-[Pd(s){CON(CH2CH3)2}{P(CH3)3}2]-
BF4 (s = Acetone-d6) (4b). In an NMR tube filled with argon
was placed trans-[PdCl(CONEt2)(PMe3)2] (30.2 mg, 76.6 mmol)
and acetone-d6 (ca. 0.3 mL) was added at room temperature to dis-
solve the complex, giving a light-brown solution. Upon cooling
2
7:1 Hz), 1.06 (3H, CH2CH3, t, JHH ¼ 7:1 Hz); 13C{1H} NMR
2
(67.9 MHz, CD2Cl2, 25 ꢁC) ꢂ 184.1 (CONEt2, t, JPC ¼ 4:9
Hz), 43.1 (CH2CH3, s), 39.5 (CH2CH3, s), 14.1 (P(CH3)3, vt,
JPC ¼ 14:2 Hz), 13.9 (CH2CH3, s); 31P{1H} NMR (202 MHz,
CD2Cl2, 25 ꢁC) ꢂ ꢂ17:6 (s). IR (KBr disc) 1574 cmꢂ1 (ꢃC=O).
Found: C, 33.53; H, 7.14; N, 3.40%. Calcd for C11H28ClNOP2Pd:
C, 33.52; H, 7.16; N, 3.55%.
ꢁ
the solution at ꢂ30 C, an acetone-d6 solution of AgBF4 (0.218
3. Synthesis of [PdCl{CON(CH2CH3)2}{(C6H5)2P(CH2)3P-
(C6H5)2}] (3): To a toluene (18 mL) solution of 2 (46.0 mg,
0.60 mmol) in a 50 mL Schlenk tube was added DPPP (248
mg, 0.60 mmol) in toluene (5 mL), and the reaction mixture
was stirred for 24 h at room temperature. Toluene was removed
under reduced pressure at room temperature, and the residue
was purified by recrystallization from CH2Cl2 (2 mL) and ether
mL, 0.352 M, 76.6 mmol) was added to cause an immediate pre-
cipitation of a white precipitate of AgCl. The NMR tube was shak-
en and allowed to cause the precipitation of a white solid. An
NMR investigation of the supernatant showed the formation of a
1
cationic carbamoylpalladium complex 4b. H NMR (270.5 MHz,
3
acetone-d6, ꢂ30 ꢁC) ꢂ 3.96 (2H, CH2CH3, q, JHH ¼ 7:1 Hz),
3
3.32 (2H, CH2CH3, q, JHH ¼ 7:1 Hz), 1.39 (18H, P(CH3)3, vt,
ꢁ
3
(10 mL) at ꢂ70 C. After removing the solvent by filtration, the
JPH ¼ 3:8 Hz), 1.22 (3H, CH2CH3, t, JHH ¼ 7:1 Hz), 1.02 (3H,
3
obtained pale-yellow blocks of crystals were washed with ether
(5 mL ꢄ 3) and dried in vacuo at room temperature, yield, 65%
(254 mg, 0.388 mmol). 1H NMR (500.2 MHz, CDCl3, 25 ꢁC) ꢂ
CH2CH3, t, JHH ¼ 7:1 Hz); 13C{1H} NMR (67.9 MHz, ace-
2
tone-d6, ꢂ30 ꢁC) ꢂ 175.6 (CONEt2, t, JPC ¼ 8:7 Hz), 43.2
(CH2CH3, s), 40.5 (CH2CH3, s), 14.5 (CH2CH3, s), 13.6
(CH2CH3, s), 13.3 (P(CH3)3, vt, JPC ¼ 14:1 Hz); 31P{1H} NMR
3
7.8–7.2 (20H, C6H5, m), 3.97 (1H, CH2CH3, dq, JHH ¼ 7:1
2
3
ꢁ
Hz, JHH ¼ 14:1 Hz), 2.77 (1H, CH2CH3, dq, JHH ¼ 7:2 Hz,
(109.4 MHz, acetone-d6, ꢂ30 C) ꢂ ꢂ17:6 (vt, JPC ¼ 14:1 Hz);
2JHH ¼ 14:4 Hz), 2.73 (1H, CH2CH3, dq, 3JHH ¼ 7:2 Hz, 2JHH
¼
19F NMR (254.0 MHz, acetone-d6, ꢂ30 C) ꢂ ꢂ144:8 (s).
ꢁ
3
2
14:4 Hz), 2.63 (1H, CH2CH3, dq, JHH ¼ 7:0 Hz, JHH ¼ 14:0
Hz), 2.55–0.87 (2H, CH2CH3 of dppp, dd,), 2.18–1.79 (2H, CH2
of dppp, m), 1.44–1.32 (2H, CH2 of dppp, m), 0.87 (3H, CH2CH3,
NMR Data for [Pd(s){CON(CH2CH3)2}{(C6H5)2P(CH2)3P-
(C6H5)2}]BF4 (s = THF-d8) (4c): 31P{1H} NMR (109.4 MHz,
2
2
THF-d8, ꢂ20 ꢁC) ꢂ 16.1 (d, JPP ¼ 59:4 Hz), ꢂ3:9 (d, JPP
¼
3
3
dd, JHH ¼ 7:1 Hz, JHH ¼ 7:1 Hz), 0.48 (3H, CH2CH3, dd,
59:4 Hz).
3JHH ¼ 7:1 Hz, JHH ¼ 7:1 Hz); 13C{1H} NMR (75.6 MHz,
Synthesis of [Pd(acetone){CON(CH2CH3)2}{P(C6H5)3}2]-
BF4 (4a). In a 25 mL Schlenk tube was placed trans-[PdCl-
(CONEt2)(PPh3)2] (204 mg, 0.266 mmol) dissolved in a mixture
of CH2Cl2 (5 mL) and acetone (1 mL). After cooling the solution
2
CD2Cl2, 25 ꢁC) ꢂ 186.0 (CONEt2, dd, JPC ¼ 24:3, 160.7 Hz),
2
3
136–128 (C6H5, m), 43.4 (CH2CH3, d, JPC ¼ 2:5 Hz), 40.1
3
1
(CH2CH3, d, JPC ¼ 3:7 Hz), 28.2 (CH2PPh2, dd, JPC ¼ 28:6
3
1
ꢁ
Hz, JPC ¼ 6:2 Hz), 27.0 (CH2PPh2, d, JPC ¼ 18:1 Hz), 19.1
to 0 C, an acetone solution of AgBF4 (0.266 mL, 1.00 M, 0.266
3
(Ph2PCH2CH2CH2PPh2, d, JPC ¼ 5:0 Hz), 13.5 (CH2CH3, s),
mmol) was added to cause the immediate precipitation of AgCl.
After removing the precipitate by filtration, pentane (15 mL)
was slowly added, and the system was allowed to stand for 3 d
to cause the deposition of colorless blocks of crystals. After re-
moving the solvent by filtration, the crystals were washed with
5 mL of pentane three times and dried at ꢂ30 ꢁC to give the ace-
tone-coordinated 4a in 97% yield. Since the crystals are prone to
lose the solvent molecules, they were kept at a low temperature in
the mother liquor before subjecting to X ray analysis.
13.2 (CH2CH3, s); 31P{1H} NMR (202.5 MHz, CD2Cl2, 25 ꢁC)
ꢂ 9.0 (d, 2JPP ¼ 69:2 Hz), ꢂ8:8 (d, 2JPP ¼ 69:2 Hz); IR (KBr disc)
1584 cmꢂ1 (ꢃC=O). Found: C, 58.21; H, 5.48; N, 2.21%. Calcd for
C32H36ClNOP2Pd: C, 58.73; H, 5.54; N, 2.14%.
4. Synthesis of trans-[PdCl{CONH(CH2CH2CH3)}{P-
(C6H5)3}2]14f (7): To an acetonitrile suspension (20 mL) of
trans-[PdCl2(PPh3)2] (510 mg, 0.726 mmol) in a 100 mL Schlenk
tube was added PrNH2 (0.298 mL, 3.63 mmol), and the reaction
mixture was stirred under a balloon pressure of CO at room tem-
perature. After the reaction for 24 h, a pale-yellow suspension was
obtained. The solvent was removed by filtration, and the residue
was purified by rꢁecrystallization from CH2Cl2 (10 mL) and ether
(40 mL) at ꢂ30 C. After removing the solvent by filtration, the
obtained crystals were washed with pentane (2 mL ꢄ 3) and dried
in vacuo. The pale-yellow blocks (220 mg, yield 40%) obtained
were identified as 7 by comparing the spectroscopic data.
1H NMR (500.2 MHz, CDCl3, 0 ꢁC) ꢂ 7.6–7.2 (30H, C6H5),
3
3.71 (2H, CH2CH3, q, JHH ¼ 7:0 Hz), 2.45 (2H, CH2CH3, q,
3JHH ¼ 7:0 Hz), 1.33 (6H, CO(CH3)2, br) 0.58 (2H, CH2CH3, t,
3
3JHH ¼ 7:0 Hz), 0.22 (2H, CH2CH3, t, JHH ¼ 7:0 Hz);
13C{1H} NMR (125.8 MHz, CDCl3, 0 ꢁC) ꢂ 220.7 (CO(CH3)2,
2
s), 168.4 (CON, t, JPC ¼ 6:5 Hz), 135–128 (C6H5), 43.3
(CH2CH3, s), 42.5 (CH2CH3, s), 30.8 (CO(CH3)2, s), 12.31
(CH2CH3,ꢁ s), 12.27 (CH2CH3, s); 31P{1H} NMR (202.5 MHz,
ꢁ
ꢁ
1H NMR (500.2 MHz, CDCl3, 25 C) ꢂ 7.3–7.8 (30H, C6H5),
CDCl3, 0 C) ꢂ 18.0 (s); 19F NMR (470.5 MHz, CDCl3, 0 C) ꢂ
3
3
4.58 (1H, NH, t, JHH ¼ 4:9 Hz), 1.94 (2H, NHCH2, dt, JHH
¼
ꢂ151:1 (s); IR (KBr disc) ꢃC=O ¼ 1681 (acetone), ꢃC=O ¼ 1613
cmꢂ1 (CONEt2). Found: C, 60.23; H, 5.06; N, 1.65%. Calcd for
C44H46BF4NO2P2Pd: C, 60.33; H, 5.29; N, 1.60%.
3
3
4:9 Hz, JHH ¼ 7:4 Hz), 0.57 (2H, CH2CH2CH3, tq, JHH ¼ 7:4
3
3
Hz, JHH ¼ 7:4 Hz), 0.38 (3H, CH3, t, JHH ¼ 7:4 Hz);
13C{1H} NMR (125.8 MHz, CDCl3, 25 ꢁC) ꢂ 180.8 (CON, t,
2JPC ¼ 5:7 Hz), 135–128 (C6H5), 43.5 (NHCH2, s), 21.8
(CH2CH2CH3, s), 11.0 (CH3, s); 31P{1H} NMR (202.5 MHz,
Synthesis of [Pd(CH3CN){CON(CH2CH3)2}{P(C6H5)3}2]-
BF4 (4a0). In a 25 mL Schlenk tube was placed complex 1
(200 mg, 0.261 mmol) dissolved in a mixture of CH2Cl2 (4 mL)
and acetonitrile (1 mL). After cooling the solution to ꢂ30 ꢁC,
an acetone solution of AgBF4 (0.261 mL, 1.00 M, 0.261 mmol)
was added to cause the immediate precipitation of AgCl. After re-
moving the precipitate by filtration, pentane (10 mL) was slowly
added, and the system was allowed to stand for 2 d at ꢂ30 ꢁC
to give colorless blocks of crystals. After removing the solvent
by filtration, the crystals were washed with 3 mL of pentane four
ꢁ
CDCl3, 25 C) ꢂ 20.1 (s).
Preparation of Cationic Carbamoylpalladium Complexes.
The cationic carbamoylpalladium complexes 4 were prepared by
treating the corresponding carbamoylchloropalladium complexes
1–3 with an acetone solution of AgBF4 at low temperature. Rep-
resentative examples of preparation of the cationic complexes are
described below. Most of the cationic complexes were prepared in