Asymmetric phase-transfer catalysis is a powerful technique that enables a wide range of transformations under mild conditions, often using inexpensive and environmentally benign reagents. By extending the applications of phase-transfer catalysis we have developed a highly diastereo- and enantioselective synthesis of functionalized indolines bearing two contiguous stereocentres, one of which is quaternary and all carbon, in a single synthetic step. The reaction proceeds with complete diastereoselectivity and with high levels of enantioselectivity (up to 99% ee). Despite the development of phase-transfer catalysis as a primary synthetic tool in organic synthesis, the mechanistic understanding of these reactions still remains a challenge, due mainly to the difficulty of studying the complex multi-phase systems. Therefore, a further aim of this project was to understand the reaction mechanism of our phase-transfer catalysed transformation. Investigations into the mechanism of our phase-transfer catalysed reaction have been carried out by studying the reaction kinetics. These have shown that the reaction follows a sigmoidal curve with an induction period present. A detailed kinetic investigation was carried out which demonstrated that an autocatalytic mechanism is operational.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:627880 |
| Date | January 2014 |
| Creators | Sharma, Krishna |
| Contributors | Smith, Martin D. |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:bfec8a97-7740-49f9-aa8f-5b97f632c21d |
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