Visible-Light-Mediated Remote Aliphatic C-H Functionalizations through a 1,5-Hydrogen Transfer Cascade
1Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
Angewandte Chemie (International Ed. in English)
|January 19, 2017
Summary
This study presents a new method for C-H bond functionalization using light and iminyl radicals in water. The process efficiently creates fused ketones and diverse molecular scaffolds.
Area of Science:
- Organic Chemistry
- Photochemistry
- Catalysis
Background:
- Unactivated C(sp3)-H bonds are challenging to functionalize selectively.
- Developing sustainable and efficient synthetic methodologies is crucial in organic chemistry.
- Radical-mediated reactions offer unique pathways for chemical transformations.
Purpose of the Study:
- To develop a novel, redox-neutral, light-mediated method for functionalizing unactivated C(sp3)-H bonds.
- To explore the formation of fused ketones and other complex scaffolds using iminyl radicals.
- To elucidate the mechanism of the proposed C-H functionalization reaction.
Main Methods:
- Utilizing a photocatalytic system for C-H bond activation.
- Employing iminyl radicals generated under light irradiation.
- Performing reactions in aqueous media to enhance sustainability.
- Conducting mechanistic studies including kinetic analysis.
Main Results:
- Successful functionalization of unactivated C(sp3)-H bonds via a 1,5-H transfer mechanism.
- Synthesis of a variety of elaborated fused ketones.
- Identification of 1,5-H transfer as the reversible, rate-determining step.
- Demonstration of access to divergent scaffolds through C(sp3)-N bond formation by tuning additives.
Conclusions:
- The presented method offers an efficient and versatile approach for C-H functionalization.
- The reaction proceeds via a unique 1,5-H transfer pathway, offering mechanistic insights.
- The methodology allows for the construction of complex molecular architectures in aqueous media.
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