Suzuki Reaction and its Mechanism, Akira Suzuki, Trans metalation, Reductive Elimination, Merits, Green synthesis

1. Suzuki Reaction and its
Mechanism
Hajira Mahmood
Ph.D. CHEMISTRY

2. Suzuki Reaction
It is an organic reaction, classified as a cross-coupling reaction, where the
coupling partners are a boronic acid and an organohalide. The catalyst being
used is a palladium complex.
• The Suzuki Reaction is an important type of coupling reaction, a designation
that encompasses a variety of processes that combine (or “couple”) two
hydrocarbon fragments with the aid of a catalyst.
• The reaction can conjoin a variety of aryl halides and alkenyl
halides with alkenyl boranes and aryl boronic acids.
• Commonly referred to as the Suzuki cross-coupling
• An important method of synthesizing many styrene, alkenes, and biphenyls.

3. Akira Suzuki
Japanese chemist
 Nobel Prize in 2010
first published the Suzuki reaction, the organic reaction of an aryl- or
vinyl-boronic acid with an aryl- or vinyl-halide catalyzed by a
palladium complex, Reported in 1979 by Akira Suzuki and N. Miyaura.

4. Mechanism of Suzuki Reaction
• Palladium catalyzed cross-coupling reactions, between an organic
halide and an organometallic reagent, that forge carbon-carbon bonds
constitute one of the central pillars of modern-day organic synthesis.
• Three sequential mechanistic events define the general catalytic cycle
1. oxidative addition of the organic halide to palladium (0) to form a
palladium (II) complex
• 2. trans metalation i.e. transfer of the organic portion of the
organometallic reagent to the palladium (II) center.
• 3. reductive elimination to form the new carbon-carbon bond and
regenerate palladium (0) catalyst.

5. Mechanism of Suzuki Reaction

6. Oxidative Addition
• The rate determining step of the catalytic cycle
• Couples the palladium catalyst to the alkyl halide which gives rise to
the organopalladium complex
• The complex is initially in the cis conformation but isomerizes to the
trans conformation
• Stereochemistry with vinyl halides are retained but inversion of
stereochemistry occurs with allylic or benzylic halide

7. Trans metalation
 The role of base is to activate the boron-containing reagent, and
facilitate the formation of R1PdOR from R1Pd-X.
 Reaction does not occur in the absence of base.

8. Reductive Elimination
 This final step gives the desired product and it also regenerates the
palladium catalyst so that it can participate again in the catalytic cycle
(I.e. making more products).
 Require the complex to revert to the cis conformation before reductive
elimination can occur

9. Merits
 Mild Reaction Conditions
 Availability of common boronic acids
 Inorganic by-products are easily removed from reaction
mixture.
 Stereoselective
 Less toxic than other competitive methods, (ie. Boronic
acids are environmentally safer and less toxic than
organostannanes)
 Reaction will take place in the presence of other
functional groups (ie. protecting group is not always
necessary)
 Relatively cheap reagents, easy to prepare, and GREEN!