Preparation of Allyl Sulfoxides by Palladium-Catalyzed Allylic Alkylation of Sulfenate Anions - PowerPoint PPT Presentation

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Preparation of Allyl Sulfoxides by Palladium-Catalyzed Allylic Alkylation of Sulfenate Anions

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Preparation of Allyl Sulfoxides by Palladium-Catalyzed Allylic Alkylation of Sulfenate Anions Guillaume Maitro, Guillaume Prestat, David Madec, and Giovanni Poli – PowerPoint PPT presentation

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Title: Preparation of Allyl Sulfoxides by Palladium-Catalyzed Allylic Alkylation of Sulfenate Anions


1
Preparation of Allyl Sulfoxides by
Palladium-Catalyzed Allylic Alkylation of
Sulfenate Anions
  • Guillaume Maitro, Guillaume Prestat,
  • David Madec, and Giovanni Poli

J. Org. Chem. 2006, 71, 7449-7454
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2
Allyl Sulfoxides
  • Allyl sulfoxides are versatile and valuable
    building blocks in organic synthesis .

  • It is proved by their use in the preparation of
    various functionalized compounds and natural
    products.


3
Palladium-Catalyzed Allylic Alkylation of Sulfur
Nucleophiles
4
Generations of Carbon-Heteroatom Bonds by
Palladium Complex
5
Synthesis of Allyl Sulfoxides
6
Mechanism of The Synthesis of Sulfenate
7
Methods of Generation of Sulfenate Anions
  • Sulfur oxidation
  • Addition-elimination reaction
  • Ring-opening reaction
  • Ring manipulation route
  • Sigmatropic rearrangement
  • Metal insertion reaction
  • Retro-Michael reaction

8
Generation of Sulfenate Anions by Sulfur Oxidation
  • Sulfenate anions are of limited stability.
  • A competitive oxidative pathway leading to
    symmetrical disulfides may occur.
  • The oxidizing agents employed up to now, m-CPBA
    and hydrogen peroxide, were not particularly well
    suited to this task.

9
Generation of Sulfenate Anions by Metal Insertion
Reaction
10
Generation of Sulfenate Anions by Ring-Opening
Reaction
11
Methods of Generation of Sulfenate Anions
  • Sulfur oxidation
  • Addition-elimination reaction
  • Ring-opening reaction
  • Ring manipulation route
  • Sigmatropic rearrangement
  • Metal insertion reaction
  • Retro-Michael reaction

12
Generation of Sulfenate Anions by retro-Michael
reaction
13
The Catalytic Cycle for Transition
Metal-Catalyzed Allylic Alkylations
14
Preparation of ß-Sulfinylesters
15
Mechanism of The Preparation of The
ß-Sulfinylesters
16
Mechanism of The Formation of Sulfenate Anions
17
Optimization of Reaction Conditions
18
Allylic Acetates
19
Palladium-Catalyzed Allylic Alkylation of
Sulfenate Anions
20
The Interconversion Equilibrium between The Two
Diastereomers
21
Palladium-Catalyzed Allylic Alkylation of
Sulfenate Anions
22
Palladium-Catalyzed Allylic Alkylation of
Sulfenate Anions
23
Allylic Alkylations in Biphasic Conditions
24
Conclusions
  • We have reported the first palladium-catalyzed
    allylation of sulfenate anions.
  • This new, smooth, and operationally very simple
    method further extends the set of sulfur-based
    nucleophiles that can be successfully allylated
    under palladium catalysis.
  • The stereogenic nature of the sulfur atom in the
    generated allyl sulfoxides, and the potential
    sulfoxide-sulfenate rearrangement associated to
    these compounds are expected to make of this
    reaction a synthetically interesting
    transformation.

25
n-BuLi/(-)-sparteine
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