Peh, GuangRong
(2016)
Oxidative C-H Activation: Convergent Fragment-Coupling approaches to Spiroacetals and the Total Synthesis of Clavosolide A.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Two one-pot oxidative cyclization strategies to spiroacetals are described herein. The first approach utilizes a Lewis acid-mediated Ferrier reaction for the initial fragment coupling followed by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-initiated oxidative carbon–hydrogen bond cleavage and cyclization. The second approach relies on a Heck cross coupling for fragment assembly followed by a DDQ-mediated dehydrogenation of enol ethers into enones and subsequent acid-induced cyclization. These methods provide mild convergent protocols to spiroketal subunits, which are ubiquitous in natural products, medicinal drugs, and chemical libraries.
Cyclopropane-substituted allylic ethers undergo carbon–hydrogen bond cleavage to form stable oxocarbenium ions upon reaction with DDQ. Significantly, in the presence of an appending nucleophile, facile ring closure occurs to yield highly functionalized tetrahydropyrans with no accompanied cyclopropane scission. This methodology was showcased during the total synthesis of the sponge-derived macrodiolide clavosolide A.
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Details
Item Type: |
University of Pittsburgh ETD
|
Status: |
Unpublished |
Creators/Authors: |
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ETD Committee: |
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Date: |
21 January 2016 |
Date Type: |
Publication |
Defense Date: |
30 September 2015 |
Approval Date: |
21 January 2016 |
Submission Date: |
6 October 2015 |
Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
Number of Pages: |
208 |
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: |
cyclopropane, carbon–hydrogen bond activation, spiroacetals |
Date Deposited: |
21 Jan 2016 21:47 |
Last Modified: |
15 Nov 2016 14:30 |
URI: |
http://d-scholarship.pitt.edu/id/eprint/26188 |
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