1
3
G
3
G
3
. A solution of G
3
G
2.5 (1.0 g, 0.34 mmol) in a mixture
3
7.24–7.37 (m, 64H). C NMR (75 MHz, CDCl ) d (ppm):
of dichloromethane and methanol (1 : 1, v/v, 30 ml) was added
to ethylenediamine (7.0 ml, 114.0 mmol), and stirred for 14 days
at room temperature upon the completion of the reaction. The
172.98, 171.48, 160.24, 160.04, 159.99, 159.91, 141.95, 141.72,
139.51, 139.45, 139.32, 137.63, 137.46, 136.86, 133.34, 133.09,
128.89, 128.68, 128.58, 128.11, 127.67, 107.90, 107.69, 106.59,
106.50, 101.67, 100.65, 70.15, 70.06, 58.56, 58.36, 58.29, 54.78,
51.65, 49.94, 49.69, 49.41, 49.16, 45.80, 36.40, 33.94, 33.72,
1
product was obtained as a white solid (1.02 g, 95%). H NMR
(
300 MHz, CDCl ) d (ppm): 2.30–3.98 (m, 150H), 4.88–4.93
3
3
1
(
m, 30H), 6.47–6.59 (m, 21H), 7.29 (br s, 40H), 7.96 (br s, 10H),
3
32.70, 32.41. P NMR (162 MHz, CDCl
3
) d (ppm): ꢀ28.56.
1
+
MS (MALDI-TOF): m/z calcd for [M + 4O + Na] : 2699.1,
9
1
1
5
3
.31 (br s, 1H). C NMR (150 MHz, CDCl ) d (ppm): 174.11,
+
73.02, 160.14, 139.23, 136.78, 128.58, 128.00, 127.56, 108.52,
[M–P(O)Ph
Elemental analysis calcd for [C167
N, 2.68%. Found: C, 76.13; H, 6.08; N, 2.19%. In situ catalyst
2
+ 4O + Na] : 2485.5; found: 2699.9; 2485.8.
07.33, 106.63, 106.46, 101.57, 100.46, 70.06, 58.11, 52.64,
157 5 16 4
H N O P
]: C, 76.73; H, 6.05;
0.00, 44.90, 44.34, 39.93, 37.59, 34.02. MS (MALDI-TOF):
+
31
m/z calcd for [M + Na] : 3211.7; found: 3213.3.
G
3
G
1
DiPPd
2
:
3
P NMR (162 MHz, CDCl ) d (ppm): 9.75.
General procedure for the synthesis of Janus dendritic
phosphines and their Pd-catalysts
G
3
G
2
DiP. To a stirred solution of a phosphonium salt
(
0.24 g, 0.81 mmol) with triethylamine (0.12 ml, 0.81 mmol)
Dendritic phosphines. The bis(hydroxymethy1)phosphonium
in dichloromethane and methanol (1 : 1, v/v, 25 ml) was added
chloride salt ([PPh
tive yields by treatment of PPh
and concentrated hydrochloric acid according to the reported
2
(CH
2
OH)
2
]Cl) was prepared in quantita-
G G (0.23 g, 0.1 mmol). The resulting mixture was refluxed
2
3
2
H with aqueous formaldehyde
for 5 h, giving G G DiP as a white solid (0.35 g, 95%).
3
2
1
H NMR (300 MHz, CDCl ) d (ppm): 1.75–3.14(m, 46H),
3
1
4
2 2 2
method. To a stirred solution of [PPh (CH OH) ]Cl and
3
.44 (s, 16H), 4.86 (m, 28H), 5.74 (br s, 3H), 6.46–6.57
1
3
m, 21H), 7.16–7.27 (m, 114H); C NMR (75 MHz, CDCl
triethylamine in dichloromethane and methanol (1 : 1, v/v) was
(
3
)
added the above prepared dendritic amine (1 equiv. –NH2).
d (ppm): 172.33, 171.79, 160.24, 160.16, 160.00, 139.50, 139.35,
The resulting mixture was heated to reflux for 2–10 h and
1
1
5
37.69, 137.52, 136.87, 133.34, 133.10, 128.90, 128.69, 128.60,
28.11, 127.66, 108.44, 106.70, 106.55, 101.69, 100.64, 70.14,
monitored by TLC. The mixture was then extracted with
dichloromethane, dried over anhydrous sodium sulfate and
filtered. Most of the solvent was removed under reduced
pressure, and the obtained residue was further purified by
precipitation into a mixture of n-hexane and ether.
3
8.35 54.81, 52.60, 49.73, 45.85, 37.53, 36.53, 33.52; P NMR
1
(
162 MHz, CDCl
3
) d (ppm): ꢀ28.53; MS (MALDI-TOF): m/z
+
calcd for [M + 8O + Na] : 4012.6, [M–P(O)Ph + 8O +
2
+
Na] : 3798.5; found: 4012.9, 3798.7. Elemental analysis calcd
for [C239H241N O P ]: C, 74.30; H, 6.29; N, 4.71%. Found:
13 20 8
Dendritic Pd-catalysts. The palladium catalysts were prepared
in situ by reacting the corresponding dendritic phosphines with
Pd(COD)Cl2 (1.0 mol equivalent per bis-phosphine unit) in
CH Cl at room temperature for 2 h. The solvents were then
C, 73.31; H, 6.62; N, 4.68%. In situ catalyst G G DiPPd :
4
3
2
3
1
P NMR (162 MHz, CDCl
3
) d (ppm): 8.84.
2
2
removed, and dried to afford the desired Pd-catalysts, which
were directly used without further purification.
G
3
G
3
3 2
DiP: G G DiP. To a stirred solution of a phosphonium
salt (0.12 g, 0.43 mmol) with triethylamine (0.06 ml, 0.43 mmol)
in dichloromethane and methanol (1 : 1, v/v, 25 ml) was added
G
3
G
0
DiP. To a stirred solution of a phosphonium salt
G
3
G
3
(0.08 g, 0.025 mmol). The resulting mixture was refluxed
for 10 h, giving G DiP as a white solid (0.13 g, 90%).
H NMR (300 MHz, CDCl ) d (ppm): 1.84–3.20 (m, 106H),
(
0.06 g, 0.21 mmol) with triethylamine (0.03 ml, 0.21 mmol) in
3 3
G
dichloromethane and methanol (1 : 1, v/v, 25 ml) was added
1
3
G NH (0.16 g, 0.1 mmol). The resulting mixture was refluxed
3
1
for 2 h, giving G G DiP as a white solid (0.17 g, 95%). H NMR
2
3.53 (s, 22H), 4.96 (d, 28H, J = 19.20), 6.53–6.67 (m, 21H),
13
7.26–7.46(m, 147H). C NMR (75 MHz, CDCl ) d (ppm):
3
0
3
(
300 MHz, CDCl
3
) d (ppm): 3.74 (s, 4H), 4.09 (s, 2H), 4.82 (s, 4H),
1
1
3
60.27, 139.35, 136.90, 133.36, 133.12, 132.79, 131.16, 130.05,
13
5
.10 (m, 24H), 6.49–6.82 (m, 21H), 7.35–7.51 (m, 60H). C NMR
75 MHz, CDCl ) d (ppm): 160.31, 160.17, 159.70, 141.44, 139.56,
39.42, 137.89, 137.73, 136.91, 133.43, 133.18, 128.71, 128.52,
28.43, 128.13, 127.93, 127.69, 108.08, 106.64, 106.53, 101.73,
28.71, 128.39, 128.13, 127.70, 106.60, 101.73, 70.23, 45.88,
31
2.05. P NMR (162 MHz, CDCl ) d (ppm): ꢀ28.80. In situ
(
3
3
1
31
catalyst G
3
G
3
DiPPd
8
:
3
P NMR (162 MHz, CDCl ) d
1
(
ppm): 8.45.
31
1
01.30, 70.21, 70.10, 69.78, 60.68, 58.16. P NMR (162 MHz,
CDCl
) d (ppm): ꢀ28.62. MS (MALDI-TOF): m/z calcd for
M–2PPh ] : 1617.7, [M–PPh ] : 1802.7; found: 1619.0, 1803.0.
3
General procedure for the Suzuki coupling reaction and catalyst
recycling
+
+
[
2
2
Elemental analysis calcd for C131H115NO P : C, 79.09; H, 5.83;
14
2
Iodobenzene or bromobenzene (1.0 mmol), phenylboronic
N, 0.70%. Found: C, 78.67; H, 5.93; N, 0.72%. In situ catalyst
3
1
2 3
acid (1.5 mmol), Cs CO (1.5 mmol) and dendritic Pd(II)
G G DiPPd: P NMR (162 MHz, CDCl ) d (ppm): 11.54.
3
0
3
catalyst (0.6–5.0 mmol) in dry 1,4-dioxane (3 ml) were placed
in a sealed tube, fitted with a teflon cap. The tube was
evacuated, flushed with nitrogen gas, after which the reaction
mixture was heated with stirring at a preferred temperature.
The conversion was determined by GC analysis with a 15 m
FactorFour capillary column.
G
3
G
1
DiP. To a stirred solution of a phosphonium salt
(
0.12 g, 0.41 mmol) with triethylamine (0.06 ml, 0.41 mmol)
in dichloromethane and methanol (1 : 1, v/v, 25 ml) was added
(0.18 g, 0.1 mmol). The resulting mixture was refluxed
3 1
G G
1
for 2 h, giving G G DiP as a white solid (0.25 g, 95%). H
3
1
NMR (300 MHz, CDCl ) d (ppm): 2.17–3.61 (m, 22H),
After the reaction was completed (monitored by GC), n-hexane
and ether were then added. The dendritic catalyst was precipitated
3
4
.91–5.01 (m, 28H), 5.67 (br s, 1H), 6.55–6.67 (m, 21H),
3
84 New J. Chem., 2012, 36, 380–385
This journal is c The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012