Synthesis of metabolites from the ascomycetes : I. The synthesis and absolute configuration of leptosphaerin : II. Approaches to the synthesis of byssochlamic acid Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/bv73c3320

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • Part I. The total synthesis of (+)-leptosphaerin (2), a metabolite of the marine Ascomycete Leptosphaeria Oraemaris (Linder) was achieved, unambiguously establishing both the relative and absolute stereochemistry of this natural product. This synthesis also resolved the long-standing question of which of the isomeric structures 1 or 2 correctly represents the structure of leptosphaerin. The target material was prepared in 12 steps, beginning from mannitol and ethyl pyruvate. In the key step a protected form of R-(+)-glyceraldehyde (3) underwent a stereospecific condensation with a 3- lithioacrylate derivative (48) to give a product (55) which was elaborated into leptosphaerin. The stereochemical outcome of this condensation was determined by means of a single crystal X-ray analysis. Part II. Two synthetic approaches to byssochlamic acid (3), a metabolite of Byssochlamys fulva, were studied. The first of these was based on a route in which a suitably functionalized 1,5-hexadiene (23) was intended to provide the substrate for an intramolecular [2+2] photocycloaddition. The impracticability of obtaining a suitable photolysis substrate caused revision of this strategy, for which the macrolide 88 became the focal intermediate. The bis phenol 89 was prepared by a sequence of reactions, the key step of which was the samarium diiodide mediated alkylation of 2',5'-dimethoxybutyrophenone (79) with 2,5-dimethoxybenzyl bromide (77). Reduction of the resulting tertiary alcohol (80) was followed by the selective protection of 80 as bisphenol 89, which underwent esterification with ethylmalonyl dichloride to give macrolide 88.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome) using Capture Perfect 3.0.82 on a Canon DR-9080C in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Made available in DSpace on 2013-07-02T15:19:47Z (GMT). No. of bitstreams: 1 PallenbergAlexanderJ1988.pdf: 793528 bytes, checksum: 46e4ec78799f30613daecb9f5e1c5496 (MD5) Previous issue date: 1988-03-16
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2013-05-29T19:10:50Z (GMT) No. of bitstreams: 1 PallenbergAlexanderJ1988.pdf: 793528 bytes, checksum: 46e4ec78799f30613daecb9f5e1c5496 (MD5)
  • description.provenance : Submitted by Kim Stowell (ksscannerosu@gmail.com) on 2013-05-24T21:23:03Z No. of bitstreams: 1 PallenbergAlexanderJ1988.pdf: 793528 bytes, checksum: 46e4ec78799f30613daecb9f5e1c5496 (MD5)
  • description.provenance : Approved for entry into archive by Deborah Campbell(deborah.campbell@oregonstate.edu) on 2013-07-02T15:19:47Z (GMT) No. of bitstreams: 1 PallenbergAlexanderJ1988.pdf: 793528 bytes, checksum: 46e4ec78799f30613daecb9f5e1c5496 (MD5)

Relationships

In Administrative Set:
Last modified: 08/10/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items