Graduation Year
2016
Document Type
Thesis
Degree
Ph.D.
Degree Name
Doctor of Philosophy (Ph.D.)
Degree Granting Department
Chemistry
Major Professor
X. Peter Zhang, Ph.D.
Co-Major Professor
Shengqian Ma, Ph.D.
Committee Member
Jon Antilla, Ph.D .
Committee Member
Mark McLaughlin, Ph.D.
Keywords
porphyrin, diazo, enantioselective, intermolecular, intramolecular
Abstract
Metal-catalyzed cyclopropanation of olefins with diazo reagents is one of the most general and efficient method to prepare cyclopropanes. The resulting cyclopropyl units are found as a basic structural element in a wide range of naturally occurring compounds and biologically active compounds, and can serve as versatile synthetic intermediates in the synthesis of multifunctionalized cycloalkanes and acyclic compounds. Since Co(II) complexes of D2-symmetric chiral amidoporphyrins [Co(D2-Por*)] were first introduced in 2004, Co(II)-metalloradical catalysis (MRC) have emerged as a new platform for asymmetric cyclopropanation. These metalloradical catalysts have been shown to be highly effective for asymmetric intermolecular cyclopropanation of a broad scope of substrates with different diazo reagents, with excellent diastereoselectivity and enantioselectivity.
This dissertation aims to develop new Co(II)-MRC based enantioselective cyclopropanation systems. It will elaborate on three types of stereoselective cyclopropanation reactions from olefins: radical cyclopropanation with α-halodiazoacetates, asymmetric bicyclization of diazoketones, and radical cyclopropanation with fluoroaryl diazomethanes. These three processes will be examined in the context of diastereo- and enantiocontrol. And also, the application of cyclopropanation products have been demonstrated, which could potentially lead to more exciting works.
Scholar Commons Citation
Cheng, Qigan, "Co(II)-Based Metalloradical Catalysis for Asymmetric Radical Cyclopropanation" (2016). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/6206
