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New methods for the construction of novel heterocycles from 1,2-Dioxines.Zvarec, Ondrej John January 2009 (has links)
Cyclic peroxides are abundant in Nature and synthetic manipulation of the peroxide linkage and alkene portion of 1,2-dioxines has established 1,2-dioxines as important compounds as both chemical building blocks and bioactive compounds. Much of the chemistry performed thus far utilizing 1,2-dioxines involves the initial rearrangement of 1,2-dioxines to γ-hydroxyenones allowing for the generation of structural motifs such as cyclopropanes, THF’s, THP’s, 1,4-diketones and natural sugars. Herein describes the synthesis of novel 1,2-dioxines with a variety of tethered functionalities and their transformations to afford novel cyclic compounds whilst maintaining the peroxide linkage intact. Chapter two outlines the intramolecular cyclisations of tethered hydroxyl and carboxylic acid moieties onto the olefin of 1,2- dioxines to generate both tetrahydrofurans and dihydrofuran-2(3H)-ones, whilst maintaining the peroxide linkage. This work presents the first examples of syn fused cyclic peroxide furans through intramolecular cyclisation of tethered hydroxyl groups. Improved methods for the oxidation of hydroxyl tethered 1,2-dioxines to carboxylic acid moieties are also reported. In addition, improved methods for intramolecular cyclisation of carboxylic acid moieties where developed to afford syn fused cyclic peroxide lactones. Furthermore, reduction of the peroxide bond enabled generation of functionalized tetrahydrofurans and dihydrofuran-2(3H)-ones which have previously been utilized as synthetic building blocks for several natural products. Chapter three reports the first examples of carbenoid insertion into the peroxide linkage of 1,2-dioxines allowing for the generation of novel bicyclic hemiacetals. Alternatively novel tricyclic cyclopropyl peroxides where generated through insertion into the olefin whilst maintaining the peroxide linage intact. Additionally, the attempted intramolecular cyclisation of diazoketone tethered bicyclic 1,2-dioxines was also probed. Furthermore, the attempted intermolecular insertion of diazoketones onto 1,2-dioxines are presented within this chapter. Finally, Chapter four outlines the intramolecular cyclisations of bromo-alkyl tethered 1,2-dioxines to furnish novel cyclic cyclopentyl peroxides whilst maintaining the peroxide linkage intact. The work presented in this chapter represents the first examples of the synthesis of syn fused cyclic cyclopentyl peroxides. In summary, this thesis outlines methodology towards the synthesis of novel cyclic peroxides from 1,2-dioxines containing tethered functional groups. / Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2009
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