Related Experiment Video
Updated: Dec 9, 2025
Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Allylic C-H functionalization via group 9 π-allyl intermediates.
Taylor A F Nelson1, Michael R Hollerbach1, Simon B Blakey1
1Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA. sblakey@emory.edu.
Group 9 Cp* transition-metal complexes enable versatile allylic C-H functionalization, expanding reaction scope to diverse olefins and coupling partners via MCp*-π-allyl intermediates. This overview details recent advances and remaining limitations in catalytic C-N, C-O, and C-C bond formation.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Organic Synthesis
Background:
- Allylic C-H functionalization is crucial for synthesizing complex organic molecules.
- Group 9 Cp* transition-metal complexes have emerged as powerful catalysts in this field.
- Previous methods were limited in substrate scope and reaction diversity.
Purpose of the Study:
- To provide a mechanistic overview of allylic C-H functionalization catalyzed by group 9 Cp* transition-metal complexes.
- To highlight recent advances and applications of these catalytic systems.
- To identify current limitations and future directions in the field.
Main Methods:
- Review of literature on catalytic allylic C-H functionalization.
- Mechanistic analysis of reactions proceeding via MCp*-π-allyl intermediates.
- Categorization of reactions based on mechanistic paradigms.
Main Results:
- Demonstrated expansion of allylic C-H functionalization to di- and trisubstituted olefins.
- Reported successful catalytic C-N, C-O, and C-C bond formations.
- Illustrated the role of MCp*-π-allyl intermediates in these transformations.
Conclusions:
- Group 9 Cp* transition-metal complexes offer a versatile platform for allylic C-H functionalization.
- Significant progress has been made in broadening substrate scope and reaction types.
- Further research is needed to overcome existing limitations and enhance catalytic efficiency.
Related Concept Videos
01:18π Molecular Orbitals of the Allyl Cation and Anion
01:27π Molecular Orbitals of the Allyl Radical
The allyl systems have identical molecular orbitals but differ in the number of π electrons....
![[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F13097.jpg&w=3840&q=75)
01:24[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement
02:38Electrophilic Addition to Alkynes: Halogenation
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
01:31Radical Substitution: Allylic Chlorination
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.