Item – Theses Canada

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OCLC number
1006927180
Link(s) to full text
LAC copy
LAC copy
Author
Chen, Gang,1971-
Title
Assymmetric oxidations using "designer yeast."
Degree
Ph. D. -- University of New Brunswick, 1999
Publisher
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, 2001.
Description
4 microfiches
Notes
Includes bibliographical references.
Abstract
A genetically engineered baker's yeast strain that overexpresses cyclohexanone monooxygenase from the soil bacterium 'Acinetobacter' sp. NCIB 9871 was used as a biological version of chiral peracids to perform asymmetric oxidations. Baeyer-Villiger oxidations of prochiral 4-substituted cyclohexanones, 2- and 3-alkyl substituted cyclopentanones, and 2-substituted cyclopentanones with functionalized side chains were performed. The results were interpreted by model studies and theoretical calculations. To examine the reactivity of this "designer yeast" in its electrophilic mode, various sulfides, dithiolanes and dithianes were tested. The complexity of whole-cell biotransformations was revealed in a series of control experiments. An alternative 'E. coli' overexpression system was tested in sulfur oxidations, and in some cases it gave improved reactivities and selectivities. A short route towards the synthesis of mevinolin analogues was designed using the yeast reagent to obtain the key chirality in the final product. This synthetic design was aimed to demonstrate the potential usefulness of the designer yeast in organic synthesis. In order to create new yeast reagents, the cloning of diketocamphane monooxygenase from 'Pseudomonas putida' ATCC17453 was initiated. The 'CAM' plasmid was isolated and two different approaches to identify the desired gene were tested. A DNA library of over 600 fragments was constructed and the subsequent cloning is an on-going project at the University of Florida.
ISBN
061254589X
9780612545892