Moningka, Remond
(2008)
Progress Toward the Total Synthesis of Guanacastepene A via a Rh(I)-catalyzed Cyclocarbonylation Reaction.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
The cyclocarbonylation reaction or the formal [2 + 2 +1] cycloaddition reaction involving alkynes, allenes, and a carbon monoxide source is a powerful methodology for the formation of cyclopentadienones. More importantly, complex ring systems can be successfully synthesized by employing the intramolecular cyclocarbonylation reaction to allenyne-containing substrates. In this thesis, progress towards the total synthesis of guanacastepene A is reported. The tricyclic skeleton of guanacastepene A has been successfully formed via a Rh(I)-catalyzed cyclocarbonylation reaction. One challenging problem of our synthetic approach is the installation of the angular methyl group at C11. It is predicted that this group can be stereoselectively appended through a hydroxyl directed cyclopropanation, oxidation, and cyclopropyl ring opening reaction sequence. SmI2 was investigated for the reductive opening of the cyclopropane. However, these conditions gave the ring expanded cyclohexanone instead of the desired angular methyl-containing cyclopentanone. Attempts to affect the cyclopropyl ring opening on a model system were investigated. Both dissolving metal (Li/NH3) and Bu3SnH reduction conditions gave ring expansion as the primary product on the model system.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
4 June 2008 |
| Date Type: |
Completion |
| Defense Date: |
15 April 2008 |
| Approval Date: |
4 June 2008 |
| Submission Date: |
24 April 2008 |
| Access Restriction: |
5 year -- Restrict access to University of Pittsburgh for a period of 5 years. |
| 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: |
Hydroxyl-directed Cyclopropanation Reaction; Reductive Cyclopropyl Ring Opening; Rh(I)-catalyzed Cyclocarbonylation Reaction |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-04242008-103928/, etd-04242008-103928 |
| Date Deposited: |
10 Nov 2011 19:42 |
| Last Modified: |
15 Nov 2016 13:42 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/7599 |
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