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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 *. J. Org. Chem. 2006 , 71 , 7449-7454. 演講者:化生四 張永å®. Allyl Sulfoxides.
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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* J. Org. Chem.2006, 71, 7449-7454 演講者:化生四 張永宏
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.
Palladium-Catalyzed Allylic Alkylation of Sulfur Nucleophiles
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
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.
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
The Catalytic Cycle for Transition Metal-Catalyzed Allylic Alkylations
The Interconversion Equilibrium between The Two Diastereomers
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.