Palladium-Neocuproine Catalyzed Aerobic Oxidation of Alcohols
FULL PAPERS
(
1
75 MHz, CDCl ): d 163.8, 150.2, 146.0, 145.7, 136.2, 136.1,
CHCH ), 1.0 ± 0.8 (t, J 7.3 Hz, 6H, 2 CH CH ); 13C NMR
3
3
2
3
28.8, 126.9, 126.5, 125.5, 122.8, 122.7, 39.6, 32.0, 30.2, 22.6, 14.0.
(75 MHz, CDCl ): d 167.3, 145.5, 136.2, 127.3, 125.5, 120.5,
3
40]
2
-(Trichloromethyl)-1,10-phenanthroline (8):[
Product
44.3, 30.3 and 30.1, 20.2 and 20.1, 12.2.
[40]
was purified via column chromatography (silica, CH Cl /
2,9-Bis(trichloromethyl)-1,10-phenanthroline (19):
mp
):
2
2
1
MeOH, 95/5, R ꢁ 0.66) to afford a pale yellow solid; yield:
214 ± 2158C (lit. 214 ± 2168C); H NMR(400 MHz, CDCl
3
f
1
1
.4 g (4.7 mmol, 90%); mp 164 ± 1668C (dec.); H NMR
d 8.44 (d, J 8.5 Hz, 2H, H4 H7), 8.33 (d, J 8.5 Hz, 2H,
13
(
8
400 MHz, CDCl ): d 9.28 (dd, J 4.4 Hz, 1.7 Hz, 1H, H9),
H3 H8), 7.96 (s, 2H, H5 H6); C NMR(100 MHz, CDCl
d 158.0, 143.3, 138.2, 129.2, 127.6, 120.5, 98.2.
):
3
3
.41 (d, J 8.5 Hz, 1H, H3), 8.33 (d, J 8.5 Hz, 1H, H2), 8.27
(
7
dd, J 8.1 Hz, 1.8 Hz, 1H, H7), 7.89 (d, J 8.8 Hz, 1H, H5),
.83 (d, J 8.8 Hz, 1H, H6), 7.67 (dd, J 8.1 Hz 4.4 Hz, 1H,
13
H8); C NMR(100 MHz, CDCl ): d 157.7, 151.3, 146.1,
3
Syntheses of Palladium Complexes
1
43.9, 138.0, 136.2, 129.3, 128.8, 128.7, 125.6, 123.4, 119.7, 98.1.
42]
1
,10-Phenanthroline-2,9-dicarboxylic acid (10):[
mp
(
Neocuproine)Pd(OAc)2:
A
solution of neocuproine
1
2
388C (dec.) (lit. 2388C); H NMR(300 MHz, DMSO- d ):
6
(5.5 mmol, 1.25 g) in anhydrous CH Cl (20 mL) was added
2
2
d 8.74 (d, J 8.2 Hz, 2H, H4 H7), 8.43 (d, J 8.2 Hz, 2H,
to a solution of Pd(OAc) (5.0 mmol, 1.12 g) in anhydrous
2
H3 H8), 8.21 (s, 2H, H5 H6), 6.4 (s broad, 2 COOH);
toluene (100 mL) at room temperature under nitrogen. The
mixture was stirred overnight and P. E. (40 ± 608C) was added
to precipitate the complex. A yellow solid was filtered off,
13
C NMR(75 MHz, DMSO- d ): d 166.1, 148.1, 144.6, 138.1,
6
1
30.4, 128.3, 123.3.
1
,10-Phenanthroline-2-carboxylic acid (11): 2-Cyano-1,10-
phenanthroline (4.9 mmol, 1.0 g) in concentrated HCl (35%,
0 mL) was stirred for 6 hours at 908C. After cooling the
washed with acetone and dried under vacuum; yield: 1.78 g
1
(4.0 mmol, 80%); H NMR(300 MHz, CDCl ): d 8.39 (d, J
3
2
8.4 Hz, 2H, H4 H7), 7.88 (s, 2H, H5 H6), 7.41 (d, J
solution was poured on ice (250 g) and concentrated NaHCO3
8.4 Hz, 2H, H3 H8), 2.89 (s, 6H, 2 ArCH ), 2.08 (s, 6H, 2
3
1
3
was added to pH ꢁ 4. A white precipitate was filtered off at
O CCH ); C NMR(75 MHz, CDCl ): d 178.5 (2 CO), 165.2
2
3
3
0
2
5
8
8C, and air-dried; yield: 1.0 g (4.5 mmol, 91%); mp 263 ± (C2 C9), 147.2 (C10a C10b), 138.5 (C4 C7), 127.9
658C (dec.); 1H NMR(400 MHz, D 2O): d 7.74 (d, J
.2 Hz, 1H, H9), 7.69 (d, J 8.2 Hz, 1H, H7), 6.94 (dd, J
.2 Hz, 5.5 Hz, 1H, H8), 6.82 (d, J 8.4 Hz, 1H, H3), 6.58, (d,
(C4a C6a), 126.7 and 126.4 (C3 C5 C6 C8), 24.5 (2
ArCH ), 23.0 (2 O CCH ).
3
2
3
Other complexes were prepared similarly. Complexation
times ran from 5 h for unhindered 8 and 9 to circa 60 h for 15
and 19.
J 8.3 Hz, 1H, H4), 6.55 (d, J 9.0 Hz, 1H, H6), 6.42 (d, J
.0 Hz, 1H, H5); 1 C NMR(100 MHz, D O): d 168.0, 149.1,
3
9
1
1
2
48.0, 144.7, 139.8, 138.0, 137.1, 131.7, 131.0, 130.4, 128.5, 126.9,
26.6.
2
-Cyano-1,10-phenanthroline (13):[43] mp 263 ± 2658C
1
Syntheses of Substrates
(
1
8
dec.); H NMR(300 MHz, CDCl ): d 9.26 (dd, J 4.4 Hz,
3
.6 Hz, 1H, H9), 8.40 (d, J 8.2 Hz, 1H, H4), 8.30 (dd, J
.0 Hz, 1.6 Hz, 1H, H7), 7.94 (d, J 8.5, 2H, H5 and H3), 7.83
2
,6-Dimethylnon-2-en-8-ol:
A
solution of citronellal
(
40 mmol, 6.16 g, 7.24 ml) in anhydrous ether (80 mL) was
(
d, J 8.8 Hz, 1H, H6), 7.72 (dd, J 8.1 Hz, 4.4 Hz, 1H, H8);
added under nitrogen to a solution of MeMgI (44 mmol) in
anhydrous ether (60 mL) at 08C. The reaction mixture was
stirred for 1 hour at 08C and then for 1 hour at reflux
temperature. The solution was cooled to 08C, hydrolysed and
neutralised with 1 M HCl to pH ꢁ 7. The organic phase was
separated; the aqueous phase was extracted with 2 Â 50 mL
ether. The combined organic phases were washed with water
13
C NMR(75 MHz, CDCl ; 12 signals!): d 151.9, 146.7, 145.3,
3
1
37.3, 136.4, 133.4, 129.9, 129.3, 126.3, 125.8, 124.2, 117.5.
2
-sec-Butyl-1,10-phenanthroline (14): A solution of sec-
BuLi (33.3 mmol, 1.3 M in cyclohexane) was added in 2 hours
at À 108C to a solution of 1,10-phenanthroline (30 mmol,
5
.4 g) in anhydrous toluene/Et O (250 mL/50 mL). The mix-
2
ture was stirred for 6 h at 08C, then overnight at room
(
25 mL) and dried over MgSO . After filtration the filtrate was
4
temperature. Work-up was as usual.[ The product was
36]
concentrated under reduced pressure and the residue was
purified via bulb-to-bulb distillation (bp 1008C/0.5 mbar) to
afford a colourless liquid; yield: 5.1 g (30 mmol, 75%);
purified via column chromatography (silica, P. E./Et O, 40/60,
2
R ꢁ 0.04) to afford a yellow syrup; yield: 1.9 g (8.1 mmol,
f
1
2
1
7%); H NMR(400 MHz, CDCl ): d 9.21 (dd, J 4.4 Hz,
1
3
H NMR(400 MHz, CDCl 3): d 5.11 (t, J 7.1 Hz, 1H,
.8 Hz, 1H, H9), 8.12 (dd, J 8.0 Hz, 1.8 Hz, 1H, H7), 8.10 (d,
CH), 3.90 (m, 1H, CHOH), 1.99 (m, 2H), 1.90 (s, 1H, OH),
J 8.3 Hz, 1H, H4), 7.66 (d, J 8.7, 1H, H5/6), 7.61 (d, J 8.7,
1
.68 (s, 3H, CCH ), 1.60 (s, 3H, CCH ), 1.55 ± 1.45 (m, 2H),
3
3
1
8
H, H5/6), 7.52 (dd, J 8.1 Hz, 4.4 Hz, 1H, H8), 7.49 (d, J
.2 Hz, 1H, H3), 3.49 (q, J 7.2 Hz, 1H, ArCH), 1.82 (m, 2H,
1.36 (t, J 6.7 Hz, 2H), 1.18 (t, J 6.3 Hz, 4H), 0.91 (dd, J
1
3
6.6 Hz, 2.0 Hz, 3H, CH ); C NMR(100 MHz, CDCl ; mixture
3
3
CH ), 1.41 (d, J 7.2 Hz, 3H, CHCH ), 0.95, (t, J 7.4 Hz, 3H,
of stereoisomers): d 131.2, 131.2, 124.8, 66.3, 65.6, 46.9, 46.8,
2
3
13
CH CH ); C NMR(100 MHz, CDCl ): d 167.9, 150.2,
37.7, 37.0, 29.5, 29.1, 25.7, 25.5, 25.4, 24.3, 23.6, 20.0, 19.3, 17.7;
2
3
3
1
1
46.2, 145.4, 136.4, 135.9, 128.7, 127.1, 126.4, 125.4, 122.5,
MS: m/z 170 (M , 15), 137 (7), 109 (55), 96 (46), 95 (46), 87
20.4, 44.6, 30.2, 20.7, 12.2.
2
(67), 82 (100), 81 (55), 69 (75), 67 (41), 55 (50), 45 (52).
,9-Di-sec-butyl-1,10-phenanthroline (15)[
36]
(mixture of
1-(p-Tolyl)-hept-3-yn-1-ol: BuLi (21 mmol, 1.6 M in hex-
ane) was added under nitrogen to a solution of 1-hexyne
(20 mmol, 1.64 g, 2.3 mL) in anhydrous THF (40 mL) at À
788C. After 1 hour stirring at À 788C, the mixture was stirred
for 1 hour at 08C and cooled again to À 788C. A solution of p-
tolualdehyde (20 mmol, 2.4 g, 2.4 mL) in THF (20 mL) was
added drop-wise and the reaction mixture was allowed to
isomers): A very pure fraction was obtained via column
chromatography (silica, CH Cl , R ꢁ 0), which solidified upon
2
2
f
1
standing; mp 65 ± 688C (uncrystallized); H NMR(300 MHz,
CDCl ): d 8.14 (d, J 8.4 Hz, 2H, H4 H7), 7.68 (s, 2H,
3
H5 H6), 7.50 (d, J 8.2 Hz, 2H, H3 H8), 3.32 (m, 2H, 2
ArCH), 2.0 ± 1.7 (m, 4H, 2 CH ), 1.46 (d, J 7.0 Hz, 6H, 2
2
Adv. Synth. Catal. 2003, 345, 1341 ± 1352
asc.wiley-vch.de
¹ 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1349