Year
2018
Degree Name
Doctor of Philosophy
Department
School of Chemistry
Abstract
Nitrogen-containing 1,3-dipoles such as azomethine ylides and zwitterionic 1,3-dipoles were utilised in cycloaddition reactions with aromatic dipolarophile partners via inter- and intramolecular modes. In addition, the reactivity of the zwitterionic 1,3-dipoles was investigated in a proposed [3 + 3] cycloaddition process. Firstly, in Chapter 2, the reaction of in-situ generated azomethine ylides with pendent nitro-aromatics was developed for the construction of potentially bioactive fused heterocycles. The initial dearomatised cycloadducts rapidly lost nitrous acid with concomitant rearomatisation forming tetracyclic isoindoline containing systems. In Chapter 3, a [3 + 2] dearomatisation reaction of highly electron-deficient 3-nitroindoles with nitrogen-containing zwitterionic 1,3-dipoles was developed. This reaction proceeds via the Pd(0)-catalysed ring-opening of a N-tosylvinylaziridine to reveal the corresponding zwitterionic 1,3-dipole, delivering densely functionalised pyrroloindolines in a diastereoselective manner. The reactions favoured the trans diastereoisomers in most cases, however, if the 4-position of the nitro-indole is occupied, a switch in diastereoselectivity towards the cis diastereoisomer is observed. In Chapter 4, efforts in achieving [3 + 3] cycloaddition between two in-situ generated 1,3-dipoles derived from 3-membered rings are detailed. A series of vinyl-substituted cyclopropanes and aziridines were reacted directly with other donor-acceptor cyclopropanes and arylaziridines under Pd(0) and Lewis acid catalysed conditions. Unexpectedly, a preference in reactivity toward dimerization, lactone formation, and Friedel–Crafts substitution with electron-rich aromatic and heteroaromatics was uncovered instead of the proposed cycloaddition.
Recommended Citation
Rivinoja, Daniel J., Cycloaddition Reactions with 1,3-Dipoles for the Formation of Complex Heterocycles, Doctor of Philosophy thesis, School of Chemistry, University of Wollongong, 2018. https://ro.uow.edu.au/theses1/600
FoR codes (2008)
0305 ORGANIC CHEMISTRY
Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.