Presentation Title

Synthesis of Furanolactone Structural Motifs via Reductive Ketyl Radical Cyclization

Faculty Mentor

Jeffrey Cannon

Start Date

18-11-2017 9:59 AM

End Date

18-11-2017 11:00 AM

Location

BSC-Ursa Minor 148

Session

Poster 1

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

The furanolactone motif is a geometrically and architecturally complex structure found in a wide range of natural products. Furan-fused lactones have been found to exhibit bioactive properties, making them biologically relevant molecules, however, they are also interesting synthetic targets for the formation of new carbon-carbon bonds due to their bicyclic structure. We have devised a novel approach to access this double-ring motif from a linear precursor utilizing dual photoredox and Lewis acid catalysis to form new bonds via a ketyl radical intermediate. Up to this point, we have optimized the photoredox cyclization conditions, and recently, primary efforts have been focused on epimerizing the anti diastereomer of the single ring product from the photoredox reaction in order to form furanolactones as well as to expand our substrate scope. We have found that in the presence of a Lewis Acid, we are able to epimerize the anti diastereomer in high yields. Furthermore, successful trials have demonstrated that our photoredox cyclization conditions are able to tolerate phenyl-substituted and methylated linear substrates for cyclization. Thus far, we have successfully synthesized a variety of target furanolactones from linear precursors and have introduced a method of forming this structural motif from the undesired single ring product. Moving forward, more work must be done to further expand our substrate scope, and it is hopeful that our novel method may later be used to synthesize a natural product containing the furanolactone motif.

Summary of research results to be presented

Thus far, key findings of this project have shown the success of utilizing dual photoredox and Lewis acid catalysis to synthesis our desired bicyclic furan-fused lactone from a beta-keto vinylogous carbonate via reductive ketyl radical cyclization. A recent focus has been to expand the scope of this project. In addition to synthesizing a basic phenyl-substituted furanolactone, this method has also been successfully applied to p-methoxyphenyl, p-bromophenyl, and o-chlorophenyl derivatives of the linear precursor. Additionally, there has been success in epimerizing the anti diastereomer of the single ring product of the photoredox reaction in order to further increase the overall yield of desired furanolactone.

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Nov 18th, 9:59 AM Nov 18th, 11:00 AM

Synthesis of Furanolactone Structural Motifs via Reductive Ketyl Radical Cyclization

BSC-Ursa Minor 148

The furanolactone motif is a geometrically and architecturally complex structure found in a wide range of natural products. Furan-fused lactones have been found to exhibit bioactive properties, making them biologically relevant molecules, however, they are also interesting synthetic targets for the formation of new carbon-carbon bonds due to their bicyclic structure. We have devised a novel approach to access this double-ring motif from a linear precursor utilizing dual photoredox and Lewis acid catalysis to form new bonds via a ketyl radical intermediate. Up to this point, we have optimized the photoredox cyclization conditions, and recently, primary efforts have been focused on epimerizing the anti diastereomer of the single ring product from the photoredox reaction in order to form furanolactones as well as to expand our substrate scope. We have found that in the presence of a Lewis Acid, we are able to epimerize the anti diastereomer in high yields. Furthermore, successful trials have demonstrated that our photoredox cyclization conditions are able to tolerate phenyl-substituted and methylated linear substrates for cyclization. Thus far, we have successfully synthesized a variety of target furanolactones from linear precursors and have introduced a method of forming this structural motif from the undesired single ring product. Moving forward, more work must be done to further expand our substrate scope, and it is hopeful that our novel method may later be used to synthesize a natural product containing the furanolactone motif.