Enantioselective%20Preparation%20of%20Allenes%20and%20Their%20Use%20in%20Organic%20Synthesis

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Enantioselective Preparation of Allenes and Their
Use in Organic Synthesis

• Literature Meeting
• February 20th 2006

By Alain Grandbois S.K. Collins Group
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Presentation Outline

• Introduction
• Enantioselective Preparation of Allenes
• Nucleophilic Attack on Alkyne
• p-Allyl Complex
• 3,3 Sigmatropic Rearrangement
• Nucleophilic Attack of Allene Anions on
  Electrophiles
• Total Synthesis of Natural Products
• Enantioselective Synthesis With Allenes
• Nucleophilic Attack of Allenyl Metals on
  Electrophiles
• Nucleophilic Attack on Carbonyl Compounds
• Photocyclisations
• 3,3 Sigmatropic Rearrangements
• Amination
• Diels-Alder Reaction
• Pauson-Khand Reaction
• Nazarov Reaction
• Substitution Reaction

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Structure of an Allene
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Allenes vs. AlkyneIn Natural Products
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Axial Chirality How does it work?
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Natural Products Containing Chiral Allenes
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Presentation Outline

• Introduction
• Enantioselective Preparation of Allenes
• Nucleophilic Attack on Alkyne
• p-Allyl Complex
• 3,3 Sigmatropic Rearrangement
• Nucleophilic Attack of the Allene Anions on
  Electrophiles
• Total Synthesis of Natural Products
• Enantioselective Synthesis With Allenes
• Nucleophilic Attack of Allenyl Metals on
  Electrophiles
• Nucleophilic Attack on Carbonyl Compounds
• Photocyclisation
• 3,3 Sigmatropic Rearrangements
• Aminations
• Diels-Alder Reaction
• Pauson-Khand Reaction
• Nazarov Reaction
• Substitution Reaction

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The First Enantioselective Preparation of an
Allene
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Chiral Propargylic Alcohol As Starting Material
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Nucleophilic Attack on Alkynes
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Nucleophilic Attack on Alkynes
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Nucleophilic Attack on Alkynes
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Nucleophilic Attack on Alkynes
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Nucleophilic Attack on Alkynes
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p-Allyl Complex
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p-Allyl Complex
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3,3-Sigmatropic Rearrangement
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Nucleophilic Attack of Allenyl Metal on
Electrophiles
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Nucleophilic Attack of Allenyl Metal on
Electrophiles
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Proposed Mechanism
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Wittig Reaction on Ketenes
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Total Synthesis of Male Dried Bean Beetle
Pheromone
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Total Synthesis of (-)-Isolaurallene
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Total Synthesis of (-)-Isolaurallene
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Total Synthesis of (-)-Isolaurallene
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(No Transcript)
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Presentation Outline

• Introduction
• Enantioselective Preparation of Allenes
• Nucleophilic Attack on Alkyne
• p-Allyl Complex
• 3,3 Sigmatropic Rearrangement
• Nucleophilic Attack of the Allene Anions on
  Electrophiles
• Total Synthesis of Natural Products
• Enantioselective Synthesis With Allenes
• Nucleophilic Attack of Allenyl Metals on
  Electrophiles
• Nucleophilic Attack on Carbonyl Compounds
• Photocyclisations
• 3,3 Sigmatropic Rearrangements
• Aminations
• Diels-Alder Reaction
• Pauson-Khand Reaction
• Nazarov Reaction
• Substitution Reaction

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Nucleophilic Attack of Allenyl Metal on
Electrophiles
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Multicomponent Coupling
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Proposed Mechanism
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Photocyclization
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Lewis Acid Catalyzed 3,3-Sigmatropic
Rearrangement
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Proposed Mechanism
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Intramolecular Amination
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Diels-Alder Reaction
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Pauson-Khand Reaction
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Nazarov Cyclization
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Substitution
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Proposed Mechanism
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Central to Axial to Central Chirality
transfertTotal Synthesis of ()-Sterpurene
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Central to Axial to Central Chirality
transfertTotal Synthesis of ()-Sterpurene
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Central to Axial to Central Chirality
transfertTotal Synthesis of (-)-Malyngolide
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Central to Axial to Central Chirality
transfertTotal Synthesis of Furanomycin
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Central to Axial to Central Chirality
transfertTotal Synthesis of Clavepictines
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Central to Axial to Central Chirality
transfertTotal Synthesis of Clavepictines (2)
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Conclusion