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Title: Stereoselective synthesis of oxygen heterocycles
Author: Pheko , Tshepo
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2013
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The thesis describes the use of y,8-unsaturated alcohol in cyclisations with various aldehydes under acidic conditions to fonn monocyclic and bicyclic heterocycles with good stereocontrol. 6-Phenylhex-5-en-2-01136 was prepared in 3 steps and 55% yield and reacted with prop anal ill the presence of oxygen· and nitrogen nucleophiles to give tri-substituted tetrahydropyrans. Interestingly 229 and 230 have an equatorial C-3 side chain whereas 232 and 235 is in axial. Furthennore reaction of 6-phenylhex-5-en-2-01 136 with aldehydes possessing aryl, nitrogen and oxygen tethered nucleophiles suitably positioned to attack the secondary carbocation giving a range of bicyclic and tricyclic scaffolds with different ring sizes in a single pot. In chapter 3, the use ofhomoallylic alcohol 329 for the synthesis of blepharocalyxin D analogues with differing substitution at the C-7 is discussed. Homoallylic alcohol 329 was reacted with electron deficient and electron rich aromatic aldehydes to give lactones which were subjected to a Grignard addition/reduction protocol to give bicyclic tetrahydropyrans.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available