Synthetic studies towards the core structure of Huperzine A

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dc.contributor.author Ward, Jarrod en
dc.date.accessioned 2020-07-08T05:04:10Z en
dc.date.available 2020-07-08T05:04:10Z en
dc.date.issued 2008 en
dc.identifier.uri http://hdl.handle.net/2292/52294 en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract The current study focused on utilising a radical cyclisation reaction of phenylselenide intermediates as the key bond-forming step in an attempt to develop a flexible, convergent, and efficient synthetic route to the core structure ofhup-A (1). In order to probe the synthetic utility of the key bond-forming step, simplified model systems were prepared. From the synthesis of these model systems it was shown that 3-pyridinyl radicals can undergo 5-exo-trig radical cyclisation in excellent yields to give hexahydroindenopyridinol (103). 2-Pyridylmethyl radicals have been shown to have utility in synthesis, undergoing 5-exo-trig radical cyclisation to efficiently give hexahydroindenopyridinol (118). Furthermore, pyridylmethyl radicals have been shown to undergo 6-exo-trig cyclisation under standard conditions in moderate yield. The mode of cyclisation of such radicals has been used to access efficiently the bicyclo[3.3.1]nonane (92) which has the same framework as hup-A. The 6-exo-trig of cyclisation has been shown to be dependant on the bulk of substituents on the cyclohexene ring, with yields increasing with the increasing size of the substituent, hi addition, a novel approach to the radical precursors by direct selenation of 2- methylpyridines has also been developed using a deprotonation/ Selenylation sequence providing access to highly functionalised compounds. The effect of a conjugated carbonyl group on the radical cyclisation reaction was also investigated and resulted in the synthesis of model compound (135). Werein is reported the first crystal structure of a bicyclo[3.3.1]nonane related to hup-A (1) compound. Attention then turned to the synthesis of more highly functionalised derivatives by the addition of 3-pyridyl and 2-pyridylmethyl Organometallics to quinols. Despite numerous attempts and revision of the synthetic strategies employed, this reaction sequence was not successful in generating any bicyclononanes. An alternative synthetic strategy utilising Diels-Alder methodology to build the ring system was successful in generating radical cyclisation precursor (200); subsequent radical cyclisation of this compound yielded target compound (221) from a 6-exo-trig mode.
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland en
dc.relation.isreferencedby UoA99180299714002091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. en
dc.rights Restricted Item. Full text is available to authenticated members of The University of Auckland only. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.title Synthetic studies towards the core structure of Huperzine A en
dc.type Thesis en
thesis.degree.discipline Chemistry en
thesis.degree.grantor The University of Auckland en
thesis.degree.level Doctoral en
thesis.degree.name PhD en
dc.rights.holder Copyright: The author en


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