Presentation Title

Dual Photoredox/Lewis Acid Catalyzed Cyclizations

Faculty Mentor

Jeff Cannon

Start Date

17-11-2018 12:30 PM

End Date

17-11-2018 2:30 PM

Location

CREVELING 98

Session

POSTER 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

The tetrahydrofuran-fused lactone motif is a functionally and stereochemically rich structure found in a wide range of natural products, many of which exhibit potential biological activity. The functional complexity of this structure presents a special challenge for synthetic efforts. Our group has discovered a novel approach to access this motif from a linear precursor utilizing dual photoredox/Lewis acid catalysis. Single electron reduction of the linear precursor produces a ketyl radical that may cyclize through an intramolecular reaction. This carbon-carbon and carbon-oxygen bond forming method has been optimized for an unsubstituted linear substrate, and recent efforts have focused on completing the substrate scope investigation. It has been shown that these conditions will tolerate a variety of functional groups. Furthermore, recent efforts have focused on expanding the application of ketyl radical cyclizations to intermolecular reactions. This will increase the utility of ketyl-olefin coupling after successful optimization of the synthesis of γ-lactones. Long-term goals include developing an enantioselective synthesis of this structure and applying our developed methods to natural product synthesis.

Summary of research results to be presented

Our group has successfully synthesized a variety of functionalized THF-fused lactones using dual photoredox/Lewis acid catalysis. These results have prompted an investigation into intermolecular ketyl-olefin couplings to afford γ-lactones. Early results show promise for the optimization of this reaction, which will later be attempted enantioselectively through integration of a chiral ligand.

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Nov 17th, 12:30 PM Nov 17th, 2:30 PM

Dual Photoredox/Lewis Acid Catalyzed Cyclizations

CREVELING 98

The tetrahydrofuran-fused lactone motif is a functionally and stereochemically rich structure found in a wide range of natural products, many of which exhibit potential biological activity. The functional complexity of this structure presents a special challenge for synthetic efforts. Our group has discovered a novel approach to access this motif from a linear precursor utilizing dual photoredox/Lewis acid catalysis. Single electron reduction of the linear precursor produces a ketyl radical that may cyclize through an intramolecular reaction. This carbon-carbon and carbon-oxygen bond forming method has been optimized for an unsubstituted linear substrate, and recent efforts have focused on completing the substrate scope investigation. It has been shown that these conditions will tolerate a variety of functional groups. Furthermore, recent efforts have focused on expanding the application of ketyl radical cyclizations to intermolecular reactions. This will increase the utility of ketyl-olefin coupling after successful optimization of the synthesis of γ-lactones. Long-term goals include developing an enantioselective synthesis of this structure and applying our developed methods to natural product synthesis.