Advancing the synthesis of aza-sulfur functional groups

Thesis

Sulfur (IV) and (VI) functionalities are ubiquitous in organic chemistry. The aza variants of these groups have drawn growing attention in discovery chemistry and display attractive features. Particular focus of this thesis relies in advancing the synthesis of two of these aza-variant; sulfinamides and sulfondiimines.

Chapter 1 reviews the syntheses and applications of sulfinamides and sulfondiimines. In addition, palladium-catalysed sulfonylative reactions using SO₂ (or its surrogates) are documented, providing a foundation for the research described in the subsequent chapters.

Chapter 2 details the discovery of Pd-catalysed sulfinamide synthesis via reductive coupling of aryl bromides and sulfinylamines. This transformation exhibits excellent functional group compatibility, and provides sulfinamides that are challenging to prepare using conventional methods. Extension of the system to cyclic alkenyl triflates is achieved via the switch of reductant. In addition, the sulfinamides prepared in this work can be easily converted into sulfur (VI) moieties.

Chapter 3 discusses the Pd-catalysed sulfinamidation of aryl chlorides under mild reaction conditions. Aryl chlorides show broader commercial availability and lower cost among aryl halides. The work developed in this chapter demonstrates an alternative choice for sulfinamides synthesis in discovery chemistry.

Chapter 4 describes the Friedel-Crafts reactivity of sulfondiimidoyl fluorides for the synthesis of (hetero)aryl sulfondiimines. Indoles are excellent nucleophiles in this reaction, and other heteroaromatics such as thiophenes, furans and pyrroles can also be successfully used. The reactivity of sulfondiimidoyl fluorides can be manipulated by changing the substituents on the N-atoms, and this allows the less reactive carbocyclic substrates, for example anisole, to be used in this transformation.

Chapter 5 summaries the research and discloses the future work of this thesis

Chapter 6 provides the experimental data and procedures for this work.

Authors: Wei, M

• DOI: 10.5287/ora-ambx0mrzm
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: sulfondiimine; catalysis; palladium; sulfinamide
• Subjects: Chemistry