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Studies toward the total synthesis of phyllaemblic acid

Casey, Tyrone Christopher (2013)
Ph.D. thesis, University of Birmingham.

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Abstract

Phyllaemblic acid is a highly oxygenated natural product isolated along with a number of related compounds from the roots of Phyllanthis emblica L. by Zhang et al. in 2000.
The roots of this shrub have been used by the people in south-east Asia as an antiscorbutic and in the treatment of diverse ailments, especially those associated with the digestive organs. A total synthesis has yet to be reported.

A concise sequence has been developed which rapidly furnishes a range of meso bridged bicyclic ketones, in good yield and with complete diastereocontrol, utilizing on an α,α’-annelation reaction of 1,3-dioxan-5-ones. The bicyclic systems are shown to adopt chair-boat conformations in both solution and in the solid state. Single
diastereomers are obtained in two cases with two different substituents. Stereochemical outcomes have been rationalized using steric and stereoelectronic arguments.

Carbon-carbon bond formation at the ketone carbonyl in these bicyclic systems is shown to be problematic. Ortho-acetal hydrolysis and diol reprotection as a bis-TBS ether provides a monocyclic system with increased ketone reactivity, allowing elaboration to an α-hydroxyaldehyde of appropriate stereochemistry for future application in a synthesis of the natural product. Preliminary studies towards this goal on a simplified model system are reported.

Type of Work:Ph.D. thesis.
Supervisor(s):Grainger, Richard S.
School/Faculty:Colleges (2008 onwards) > College of Engineering & Physical Sciences
Department:School of Chemistry
Subjects:QD Chemistry
Institution:University of Birmingham
ID Code:4049
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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