Design and synthesis of novel chiral iodine (III) reagents for enantioselective synthesis

Alharbi, Haifa 2021. Design and synthesis of novel chiral iodine (III) reagents for enantioselective synthesis. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Chiral hypervalent iodine reagents have been used in a broad range of enantioselective oxidative transformations. The high utility of hypervalent iodine reagent in organic synthesis is because of their low toxicity, environmentally friendly nature, unique reactivity, and ease of availability. Although, the design of alternative chiral hypervalent iodine reagents is still highly desirable to reach the highest enantioselectivity for challenging transformations. In this thesis, chiral iodoarenes possessing a chiral C–N bond have been designed using a simple amide formation strategy. The obtained iodoarenes are synthesised as racemates with with SC–N and RC–N configurations, interesting stereochemistry is observed in the generated anilides. However, N-alkylated anilides with the 3° anilide core are exhibited with acceptable reactivities in various symmetric reactions compared with the corresponding reagents with the 2° anilide core. A new family of hypervalent iodine compounds with axial chiral backbones possessing restricted rotation around the CAr–N axis has been synthesised as diastereoisomers. Different enantioselective transformations are investigated by using axial chiral iodoarenes in either stoichiometric or catalytic applications. Moreover, the stereoselective α-oxytosylation of Haifa Alharbi PhD Thesis 2021 v ketones are controlled by CAr–N axial chiral iodoarenes to reach high enantioselectivities of up to 80% ee and good yields of up to 96% under the developed conditions. Finally, a novel class of chiral iodoarenes possessing a stereogenic sulfoximine is designed using the reported procedures. Introducing chirality through stereogenic sulfoximine instead of sulfoxide is because the chirality of sulfoxide moiety is lost during the facile overoxidation to sulfones under the oxidative conditions to form iodine (III) reagents. The chiral induction of sulfoximines of these designed iodoarenes is investigated in various asymmetric catalytic reactions. However, the oxidation of these chiral iodoarenes is examined, but they seemed to be difficult to oxidise to the corresponding hypervalent iodine reagents.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Chemistry
Date of First Compliant Deposit:	10 January 2022
Last Modified:	03 Aug 2022 01:48
URI:	https://orca.cardiff.ac.uk/id/eprint/146488

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