Development and optimization of photoredox-mediated methine epimerization

Reactions that edit the stereochemistry of individual atoms are enabling tools in synthetic chemistry. The Wendlandt lab has developed a sequential H-atom abstraction and donation strategy to synthesize rare sugars from biomass platform molecules such as D-glucose. Efforts to apply this strategy to the epimerization of steroids gave poor results and demonstrated limited selectivity, but insights gained from this work were used to develop a hypothesis for epimerization. We proposed that H-atom abstraction and donation occur to release diaxial strain and form the most conformationally stable isomer. This hypothesis guided the development of an epimerization method for methine stereocenters. This work describes the optimization and development of methine epimerization of isomenthyl acetate. The epimerization of tertiary alkyl stereocenters is also applied to access an otherwise synthetically challenging stereochemical outcome from a Diels-Alder reaction sequence. Data from primary literature and mechanistic experiments are used to provide a proposed mechanism through which this epimerization proceeds.

Name thesis:degree_name

Master

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Chemistry

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2021

Author dc:creator

• Wang, Kathleen J

Advisor dc:contributor.advisor

• Wendlandt, Alison E

Statement dc:rights

• In Copyright - Educational Use Permitted
• Copyright MIT

Licence dc:rights.uri

• http://rightsstatements.org/page/InC-EDU/1.0/

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/139303

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/139303