chapter 2 palladium catalysts in suzuki cross- coupling reaction

As a result, organic group or hydride is transferred to Pd (Figure 2.7.). A driving force
for the reaction called transmetallation, is due to the difference in the electro negativities
of two metals (Tsuji 1995).
L
R X
Pd
L
M - R'
L
R
L
R'
Pd M
X
Figure 2.7. Transmetallation
(Source: Tsuji 1995)
L
R R'
Pd
L
+
MX
M: main group metal
In Suzuki reactions, transmetallation between organopalladium (II) halides and
organoboron compounds does not occur readily due to the low nucleophilicity of
organic group on boron atom. However, the nucleophilicity of organic group on boron
atom can be enhanced with base giving the corresponding “ate” complexes (Miyaura
and Suzuki 1995).
2.2.1.3. Reductive Elimination
Reductive elimination is simply the reverse reaction of oxidative addition. In
this step, two carbon metal bonds are broken (Tsuji 1995). The catalytic cycle is
completed by reduction of the Pd II species into a Pd 0 species and finally coupling
product forms (Figure 2.8.).
L
L
Pd II
R
R' 2L
L
L
Pd 0
Figure 2.8. Reductive Elimination
(Source: Tsuji 1995)
L
L
+
R R'
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