Vinyl sulfonates : a platform for novel substrates of biological importance

• Main Author: Edetanlen-Elliot, O.
• Published: University College London (University of London) 2011
• Subjects: 540
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.565194

Sulfonamides constitute a vital and diverse class of therapeutic agents. Their means of synthesis has often involved the use of unstable sulfonyl chloride species; however, recent research has established pentafluorophenyl (PFP) and trichlorophenyl (TCP) sulfonate esters as a useful stable alternative to such species. This thesis describes an exploration into the reactivity of the bifunctional acceptors pentafluorophenyl vinyl sulfonate and trichlorophenyl vinyl sulfonate. Intermolecular alkyl radical addition to trichlorophenol vinyl sulfonate mediated by both 1-ethylpiperidinium phosphate (EPHP) and tributyltin hydride was carried out effectively to generate a library of alkyl sulfonates. Notably, this was extended to the synthesis of a bifunctional alkyl PFP/TCP sulfonate via a double radical addition protocol which was envisaged could be useful in determining the reactivity between PFP and TCP. 1,3-Dipolar cycloaddition reactions were carried out effectively at the electron-deficient olefinic portion of the vinylsulfonates to provide functionalized sulfonate esters with excellent regioselectivity. Addition of an α and a β substituent to vinylic portion of PFP and TCP vinyl sulfonate changed the electronics and sterics of the sulfonates, however functionalised esters with great regioselectivity could still be synthesised.