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Title: Enantioselective desymmetrisation towards the synthesis of Daphniphyllum alkaloids
Author: Ellis, Samuel R.
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2019
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Chapter One introduces the Daphniphyllum alkaloids and the Calyciphylline A- type alkaloid sub-family, including proposed biosyntheses and recently reported total syntheses. The morphan core is introduced, and methods for its synthesis are dis- cussed, with a focus on enantioselective desymmetrising cyclisations. Chapter Two details the development of a Pd(II)/secondary amine co-catalysed desymmetrising cyclisation for the enantioselective synthesis of the morphan core. The method addresses several limitations of previous methods, and provides access to a broad range of products including trisubstituted alkenes. Chapter Three details the preparative synthesis of the morphan core via an enantioselective desymmetrisation reaction on up to 20 g scale. Functionalisation of the bicyclic core is discussed, including a diastereoselective hydrogenation to afford the desired stereochemical configuration. Chapter Four describes the synthesis of the tetracyclic core common to many Daphniphyllum alkaloids. An intramolecular Michael addition reaction is used to form the five-membered lactam, while the seven-membered ring is constructed by ring closing metathesis. Chapter Five details a range of synthetic strategies investigated in an attempt to construct the pentacyclic core of the Calyciphylline A-type alkaloids in an effort to achieve a total synthesis. Some of the key approaches investigated include an aldol condensation, a 5-endo-dig cyclisation, and a [3+2] cycloaddition.
Supervisor: Dixon, Darren J. Sponsor: Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Chemistry, Organic