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Figure 3.20
(dtbnp)Pd(allyl)Cl versus in situ-generated Pd
2
(dba)
3
/dtbnp.
Table 3.3 Evaluation of LPd(p-allyl)Cl precatalysts in amination reactions.
Me
N
Br
NHMe
catalyst, NaO
t
-B
u
+
toluene, rt
MeO
MeO
Conversion
a
(%)
Entry
Catalyst (mol%)
Time (h)
1
(dtbnp)Pd(allyl)Cl (1.0)
6
99
2
(dtbnp)Pd(crotyl)Cl (1.0)
3
100
3
(Q-Phos)Pd(allyl)Cl (1.0)
6
97
4
(Q-Phos)Pd(crotyl)Cl (1.0)
3
100
5
(Q-Phos)Pd(crotyl)Cl (0.5)
18
99
6
(Q-Phos)Pd(crotyl)Cl (0.1)
18
95
7
[p-Me
2
NC
6
H
4
(t-Bu)
2
P]Pd(allyl)Cl (1.0)
22
18
8
[p-Me
2
NC
6
H
4
(t-Bu)
2
P]Pd(crotyl)Cl (1.0)
22
95
9
(t-Bu
3
P)Pd(crotyl)Cl (1.0)
3
100
a
Conversion determined by GC analysis.
ligand were therefore evaluated.
112
A number of additional p-allyl and crotyl
P-based precatalysts (Figure 3.19) were prepared and investigated in ami-
nation, Suzuki-Miyaura and a-arylation reactions.
112
The general trend ob-
served with amination reactions at ambient temperature was that Pd-crotyl
complexes showed higher activities than the corresponding Pd-allyl pre-
catalysts (Table 3.3, Entries 1 versus 2, 3 versus 4 and 7 versus 8). This may
indicate that the activation pathway to the catalytically active species is more
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