Brizgys, Gediminas J.
(2011)
Diastereoselective Piperidine Synthesis through DDQ-Mediated Oxidative Cyclization of Enamides, N-Vinyl Carbamates, and N-Vinyl Sulfonamides.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
The DDQ-mediated oxidative cyclization chemistry that was previously developed in our group for the synthesis of tetrahydropyrones from allylic and benzylic ethers has been expanded for use with enamides, N-vinyl carbamates, and N-vinyl sulfonamides to synthesize piperidine rings. This chemistry provides a new oxidative method to generate N-acyliminium and N-sulfonyliminium ions. Cyclization onto the oxidatively generated α,β-unsaturated N-acyliminium and N-sulfonyliminium ions has been performed with a variety of tethered nucleophiles. The cyclization reaction suffers no difficulties in regards to chemoselectivity or over oxidation. Moreover, the resulting unit of unsaturation in the products provides an additional synthetic handle not generated through more classical iminium ion chemistry. Significantly, stereocontrol in the reaction was achieved through the use of (E)- and (Z)-allylsilanes and silyl enol ethers. Transition state models were formulated through information obtained from studies of monocyclic and bicyclic compounds synthesized through the oxidative cyclization reaction. Finally, the reaction was made catalytic through regeneration of DDQ via oxidation of the DDQ byproduct by Mn(OAc)3. This chemistry provides a powerful new method for generating nitrogen heterocycles and will provide new ways of accessing alkaloids.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Brizgys, Gediminas J. | gjb11@pitt.edu | GJB11 | |
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| ETD Committee: |
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| Date: |
14 September 2011 |
| Date Type: |
Completion |
| Defense Date: |
1 August 2011 |
| Approval Date: |
14 September 2011 |
| Submission Date: |
4 August 2011 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Acyliminium; Cyclization; DDQ; N-Acyliminium; N-Sulfonyliminium; Oxidation; Piperidine; Sulfonyliminium |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-08042011-143144/, etd-08042011-143144 |
| Date Deposited: |
10 Nov 2011 19:57 |
| Last Modified: |
15 Nov 2016 13:48 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/8895 |
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