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Title: The cycloreversion/cycloaddition route to the histrionicotoxins
Author: Hodges, A.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2004
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The histrionicotoxins are a family of alkaloids isolated from the neotropical poison arrow frog Dendrobates histrionicus. Recent work within the group has resulted in the total synthesis of a number of the histrionicotoxins utilising a novel tandem hydroxylamine-alkyne cyclisation/nitrone cycloaddition route. (Fig. 3545A) Chapter 3 describes the elucidation of factors controlling the regiochemical outcome of the cycloaddition using model studies. The styrene adduct 3.3 was synthesised form hydroxylamine 3.6 via a hydroxylamine-alkyne cyclisation followed by an intermolecular nitrone cycloaddition. A range of intramolecular dipolarophiles were then introduced and the product ratio of the adducts 3.1 and 3.2 formed on cycloreversion/cycloaddition was investigated. (Fig. 3545B) Chapter 4 describes synthetic studies towards the synthesis of (-)-histrionicotoxin 1.62 via a direct hydroxylamine-alkyne cyclisation route. The 6,5,5-adduct 2.88 was synthesised and attempts to isomerise the adduct to the 6,5,5-adduct 4.1 are reported. (Fig. 3545C) Chapter 5 describes attempts to develop an alternative direct route to the histrionicotoxin core via an oxime-epoxide cyclisation/nitrone cycloaddition strategy. (Fig. 3545D) Synthetic work towards the synthesis of the oxime 5.2 is reported.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available