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Title: Chiral hypervalent iodine mediated enantioselective phenol and naphthol dearomatisation : a rapid access to oxazoline based spirocycles
Author: Tariq, Muhammad Umair
ISNI:       0000 0005 0287 0365
Awarding Body: University of Huddersfield
Current Institution: University of Huddersfield
Date of Award: 2020
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This thesis describes an investigation into the dearomatisation reactions of phenols and naphthols catalysed by in situ generated hypervalent iodine(III) species, thereby producing a range of spirooxazoline based compounds in achiral and enantio-enriched forms. The first part of this dissertation illustrates the synthesis of spiro-oxazolines via oxidative dearomatisation of phenol and naphthol amides mediated by 4-iodotoluene as catalyst and mCPBA as terminal oxidant. Different iodoarenes, catalysts, and solvents were scanned, however, 4- iodotoluene and mCPBA provided the best results in hexafluoroisopropanol (HFIP). It was observed that altering the oxidant, iodoarene and solvent led to diminished yields in most cases. The stoichiometric and catalytic versions of the cyclisation were also successfully developed. The second part of this thesis details the synthesis of novel chiral iodoarenes bearing chiral appendages. A range of novel iodoarenes possessing chiral ureas, lactates, amides and carbamates were synthesised in good to excellent yields. The newly synthesised chiral iodoarenes were then employed and studied in the intramolecular oxidative dearomatisation reactions of naphthol amides to obtain racemic and chiral oxazoline based spirocycles. A significant increase in the enantioselectivities was observed when alcoholic solvents were used as additives in dichloromethane or chloroform at –20 °C. In the presence of excess alcoholic solvent like ethanol, methanol and HFIP, poor selectivities were observed.
Supervisor: Moran, Wesley Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Q Science (General) ; QD Chemistry