Heterobimetallic complexes in organic synthesis
thesisposted on 30.10.2018 by David T. Rutherford
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Heterobimetallic cobalt-molybdenum-cyclo-penta-dienyl-alkynyl-penta-carbonyl complexes have been demonstrated to act as efficient substrates for the Pauson–Khand cycloaddition under appropriate conditions. The inherent chirality present in the heterobimetallic core has been shown to efficiently promote a stereoselective variant of the Pauson–Khand reaction. The unique mode of stereoinduction in contrast to existing methodology has enabled the first stereospecific Pauson–Khand reaction to be realised in the absence of an external source of chirality. The scope of heterobimetallic alkyne complexes for more general asymmetric organic synthetic transformations has been briefly addressed. The heterobimetallic core has been shown to promote moderate to high levels of stereocontrol on addition of nucleophiles to remote centres of complexed propargylic aldehydes. In light of the potential use of heterobimetallic complexes in organic synthesis a new robust and experimentally facile route for complex generation has been developed. Employing this route heterobimetallic complexes cim be rapidly and routinely generated avoiding specialist techniques or apparatus. Chapter 1 provides a brief overview of the Pauson–Khand reaction and developments in this field. Chapter 2 highlights our work utilising hereobimetallic alkyne complexes as substrates in the Pauson–Khand reaction, their use in more general synthetic transformations and the development of a facile but robust route for their synthesis. Chapter 3 provides experimental data for our studies.