Presentation Title

Diastereoselective Synthesis of Unnatural Amino Acids via an Auxiliary-Directed Aldol Reaction

Faculty Mentor

Jeffrey Cannon

Start Date

17-11-2018 12:30 PM

End Date

17-11-2018 2:30 PM

Location

CREVELING 92

Session

POSTER 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

This project is aimed at developing a diastereoselective synthesis for unnatural amino acids via an auxiliary-directed aldol reaction. Our synthetic method involves the use of Ellman’s chiral auxiliary to direct the stereochemistry of the reaction. Currently, the reaction yields multiple product diastereomers. Diastereomers are molecules composed of atoms with identical connectivities but different configurations. Producing multiple diastereomers is problematic because the function of biological molecules is highly dependent on the shape of the molecule. Our goal is to optimize methodology in order to define a synthetic method that produces only one diastereomer. This optimization will include measuring the effect of both electrophile concentration and metal additives on the selectivity of the reaction. This reaction’s ability to create complex molecules of a single orientation would be very useful in reducing waste and increasing efficiency in the laboratory. This is because without a diastereoselective method, isolating a single diastereomer would involve synthesizing both diastereomers and then separating out and discarding the unwanted diastereomer. This project is worthwhile because proving that the chiral auxiliary has the ability to direct product stereochemistry would provide a foundation for much more complex chemistry. Further, enhancing access to synthetic amino acids is important because amino acids are essential for biological functioning as they code for the proteins that allow our bodies to run properly.

Summary of research results to be presented

To date, we have optimized the imine reduction (necessary to make starting material) and successfully carried out an aldol reaction with our unsubstituted amino ester substrate. Currently, two enantiomers are being produced in the aldol reaction. We determined this by first cleaving the sulfinyl group from our aldol products under acidic conditions and then introducing a Boc-protecting group. These new compounds were then compared to NMR data of known compounds. Thus, we were able to convert two aldol products to known molecules in order to determine their composition. Trials aimed at finding conditions to increase reaction stereoselectivity are still underway. Ultimately, I aim to find conditions that favor a single enantiomer. This will help demonstrate the capacity of Ellman’s auxiliary to direct product stereochemistry.

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

Diastereoselective Synthesis of Unnatural Amino Acids via an Auxiliary-Directed Aldol Reaction

CREVELING 92

This project is aimed at developing a diastereoselective synthesis for unnatural amino acids via an auxiliary-directed aldol reaction. Our synthetic method involves the use of Ellman’s chiral auxiliary to direct the stereochemistry of the reaction. Currently, the reaction yields multiple product diastereomers. Diastereomers are molecules composed of atoms with identical connectivities but different configurations. Producing multiple diastereomers is problematic because the function of biological molecules is highly dependent on the shape of the molecule. Our goal is to optimize methodology in order to define a synthetic method that produces only one diastereomer. This optimization will include measuring the effect of both electrophile concentration and metal additives on the selectivity of the reaction. This reaction’s ability to create complex molecules of a single orientation would be very useful in reducing waste and increasing efficiency in the laboratory. This is because without a diastereoselective method, isolating a single diastereomer would involve synthesizing both diastereomers and then separating out and discarding the unwanted diastereomer. This project is worthwhile because proving that the chiral auxiliary has the ability to direct product stereochemistry would provide a foundation for much more complex chemistry. Further, enhancing access to synthetic amino acids is important because amino acids are essential for biological functioning as they code for the proteins that allow our bodies to run properly.