Jayasuriya, Nilukshi Renuka
(2007)
Asymmetric Alkenyl Zirconocene/Zinc Additions to Aldehydes and Synthetic Efforts Toward Pseudotrienic Acid A.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The in situ hydrozirconation-transmetalation-aldehyde addition process is a convenient method for the generation of allylic alcohols. Ongoing research has focused on enhancing the enantioselectivity and substrate scope of this process and will be the focus of Chapter 1. Investigations have shown that both amino alcohols and amino thiols show moderate to high enantioselectivity. Non-linear effects were analyzed in order to gain mechanistic insight into the asymmetric addition process. Additionaly, analogues of both classes of ligands have been synthesized and evaluated. Amino thiol ligands tend to show the highest enantioselectivities due to the higher affinity of sulfur for zinc over zirconium. A new class of valine-based ligands was identified to be quite effective, in terms of ligand loading and % ee in the formation of allylic alcohols. In Chapter 2, progess toward pseudotrienic acid A is discussed. The goal of this project was the synthesis of pseudotrienic acid A utilizing alkenylzirconium/zinc methodology cultivated in the Wipf group and to elucidate the absolute configuration at C(20) of the target molecule. A brief summary of the only reported synthesis of pseudotrienic acid B by Cossy et al. is outlined, followed by the retrosynthetic plan and synthesis of the 3 main fragments of this molecule. Lastly, the current progress towards the coupling of these fragments is examined.
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| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
20 September 2007 |
| Date Type: |
Completion |
| Defense Date: |
5 July 2007 |
| Approval Date: |
20 September 2007 |
| Submission Date: |
6 August 2007 |
| 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: |
allylic alcohol; chiral ligands; enantiomeric excess; enantioselective alkenylzinc addition |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-08062007-200733/, etd-08062007-200733 |
| Date Deposited: |
10 Nov 2011 19:57 |
| Last Modified: |
15 Nov 2016 13:48 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/8937 |
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