Aldehydic C-H Amination Reactions via Co(II)-Based Metalloradical Catalysis and Construction of Novel Chiral meso-Amidoporphyrin Ligands

Author

Christopher Lee Lizardi, University of South FloridaFollow

Graduation Year

2015

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Department

Chemistry

Degree Granting Department

Chemistry

Major Professor

X. Peter Zhang, Ph.D.

Committee Member

Jon Antilla, Ph.D.

Committee Member

Edward Turos, Ph.D.

Committee Member

Shengqian Ma, Ph.D.

Keywords

aldehyde, azide, catalysis, chiral, cobalt, porphyrin

Abstract

Medium-sized organic ring synthesis poses a seemingly insurmountable challenge, and because of this it is a field under immense investigation. Heterocyclic containing medium-sized rings are common structural motifs in nature, which has caused researchers to investigate their potential biological activity and properties as materials. This research focused on the grand challenge of medium-sized heterocyclic ring synthesis, providing the synthesis community with new tools to generate these highly evasive products, while elucidating energetic and geometric properties of one of Nature's least understood organic ring systems.

Cobalt(II)-Amidoporphyrins, [Co(D₂-Por)], are an emerging class of metalloradical catalysts (MRC) which can facilitate a wide range of atom and group transfer reactions. A strategy was employed using [Co(D₂-Por)] to carry out an intramolecular C-H amination reaction using sulfamoyl azides as the radical nitrene source to aminate the highly reactive aldehydic C-H bond. This newfound reaction allowed for the generation of previously unobtainable medium-sized heterocycles, which surprisingly provided a racemic mixture of chiral medium-sized rings.

A wide array of chiral amidoporphyrins including meso-heteroatom containing porphyrins were synthesized as well during the course of research to probe their potential as new chiral ligands for the emerging field of cobalt(II)-amidoporphyrin catalyzed MRC system. A practical synthetic scheme was discovered employing the highly selective Zn(II)-bromoporphyrin synthon to generate a new library of chiral amidoporphyrin ligands for the MRC system through well-established cross-coupling methodologies.

Scholar Commons Citation

Lizardi, Christopher Lee, "Aldehydic C-H Amination Reactions via Co(II)-Based Metalloradical Catalysis and Construction of Novel Chiral meso-Amidoporphyrin Ligands" (2015). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/5526