Lawrence, Jean-Marc Irvin Anthony
(2022)
Environmentally Benign Method Development Towards the Synthesis of Oxygen-Containing Heterocycles.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
This is the latest version of this item.
Abstract
Oxygen-containing heterocycles are highly diverse and attractive targets in chemical synthesis that are prevalent in many biologically active natural products. Synthesizing these structures in an environmentally friendly manner can increase the use of these methods and their applicability in industry and medicinal chemistry. This document describes a dehydrative Re2O7-catalyzed approach in the activation of 1,3- and 1,5-monoallylic diols, which generate an allylic cation intermediate that is captured by a pendent alcohol to synthesize 3,4-dihydropyrans. The 2,6-trans-isomer was determined to be the kinetic and thermodynamically favored isomer. A substrate scope is developed to determine the functional group tolerance, and stereocontrol is enhanced through the incorporation of a pendent stereocenter on the dihydropyran ring. Furthermore, an investigation of the mechanism is shown through the manipulation of alkene geometry and stereochemistry to discover a unique SNi mechanism.
Electrochemical oxidative C−H functionalization is an advantageous way of increasing molecular complexity with high functional group tolerance while minimizing cost and waste. Kinetically slow oxidations followed by C−C and C−O bond formation present challenges in the effective turnover of catalytic oxidants under anhydrous conditions due to low steady-state concentrations of reduced oxidant. TEMPO-based oxoammonium salts are effective hydride abstracting reagents in the oxidation of ethers, amines, and carbamates to generate excellent electrophiles. Results described herein show that intermediate cation stability, oxidant strength, overpotential, and concentration dictate the rate of electrochemical regeneration of oxoammonium salts in the oxidation of benzylic and allylic ethers. Integrating these factors leads to a new method that synthesizes a diverse substrate scope of oxygen and nitrogen-containing heterocycles, changing the approach toward kinetically slow oxidations in future electrochemical methods.
Share
| Citation/Export: |
|
| Social Networking: |
|
Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Lawrence, Jean-Marc Irvin Anthony | jel190@pitt.edu | jel190 | |
|
| ETD Committee: |
|
| Date: |
12 October 2022 |
| Date Type: |
Publication |
| Defense Date: |
28 June 2022 |
| Approval Date: |
12 October 2022 |
| Submission Date: |
12 July 2022 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
302 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Alcohols, Cations, Cyclization, Electrochemistry, Catalysis, Oxidation, C-H Functionalization |
| Date Deposited: |
12 Oct 2022 14:58 |
| Last Modified: |
12 Oct 2022 14:58 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/43325 |
Available Versions of this Item
-
Environmentally Benign Method Development Towards the Synthesis of Oxygen-Containing Heterocycles. (deposited 12 Oct 2022 14:58)
[Currently Displayed]
Metrics
Monthly Views for the past 3 years
Plum Analytics
Actions (login required)
 |
View Item |
![[feed]](/images/feed-icon-32x32.png){kind=icon}