Stevens, Benjamin Dawson
(2007)
Applications of Iridium-Catalyzed Isomerization Claisen Rearrangements (ICR) to Complex Molecule Synthesis.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The iridium-catalyzed isomerization Claisen rearrangement (ICR) methodology developed in theNelson group has provided access to a broad range of diastereomerically enricheddisubstituted unsaturated aldehydes. Allylsilyl aldehydes produced by the ICR reaction havebeen further elaborated into substrates for highly diastereoselective intramolecular Hosomi-Sakurai annulation reactions. The Sakurai annulation has proven to be particularly powerfulwhen carried out in tandem with intramolecular aldol or Mannich reactions to form complexfused ring systems. An attempted strategic application of this methodology to the synthesis ofthe Rauwolfia alkaloids reserpine and yohimbine is detailed.Vinyl boronic esters have been demonstrated to be effective precursors for the ICRreaction providing diastereomerically enriched boronic aldehydes. The potential forintramolecular chelation between the newly formed aldehyde and proximal boronic ester hasbeen investigated. The boron functionality has proven to be useful for accessing alkoxy- andaryl-substituted compounds that are typically unavailable from the ICR reaction. A synthesis ofthe plant growth inhibitor penieone has been explored in order to demonstrate the practicalapplication of this methodology to complex molecule construction.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Stevens, Benjamin Dawson | bes7@pitt.edu | BES7 | |
|
| ETD Committee: |
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| Date: |
19 September 2007 |
| Date Type: |
Completion |
| Defense Date: |
21 March 2007 |
| Approval Date: |
19 September 2007 |
| Submission Date: |
23 November 2006 |
| 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: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Diastereoselective ring formation; Isomerization; Penienone; Sakurai; Yohimbine; Intramolecular aldol; Reserpine; Intramolecular Mannich; Claisen rearrangement; Boron chelation |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-11232006-121146/, etd-11232006-121146 |
| Date Deposited: |
10 Nov 2011 20:05 |
| Last Modified: |
15 Nov 2016 13:52 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/9769 |
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