New Methods for Allenyl Sulfoxide Formation and Interconversion, and the Synthesis of Partially Deuterated 2-Octenylsuccinic Anhydride
Part 1: Allenes are of interest due to their potential in stereoselective reactions and value in natural product synthesis. Research in the Schwan group has focused on the reactions of sulfenate anions, or sulfenates, which are the conjugate base of sulfenic acids. The main focus of this project was to synthesize allenyl sulfoxides via a [2,3]-sigmatropic rearrangements of sulfenate esters. The first objective was to synthesize a series of thioimides to react with substituted propargyl alcohols, forming sulfenate esters which then transform into allenes. The second objective was to investigate the interconversion of the allenyl sulfoxides via sulfenate release and quench with an alkyl halide. Five allenyl sulfenate precursors were successfully synthesized, however only one was able to form the corresponding allenyl sulfenate anion. The allenyl sulfenate precursors demonstrated additional reactivity when treated with sulfenate releasing conditions. In summary, this study determined novel methods of preparing allenyl sulfoxides. Part 2: Alkenyl substituted succinic anhydrides have value in medicinal and food industries as starches and other sugars can be modified with the anhydrides to fine tune properties. The alkyl chain provides hydrophobicity to the compounds and allows the modified compounds to be amphiphilic. Prof. John Dutcher in the Physics Department at the University of Guelph studies phytoglycogen, a polymer of glucose. The Dutcher group noticed an interesting interaction between phytoglycogen and 2-octenylsuccinic anhydride in aqueous solution and used neutron scattering as a method of analysis. By using deuterated 2-octenylsuccinic anhydride in their modification of phytoglycogen, the data could be compared to their neutron scattering of unlabeled 2-octenylsuccinic anhydride modification. The objective of this project was to therefore synthesize partially deuterated 2-octenylsuccinic anhydride. The synthesis involved a Grignard reaction between vinylmagnesium bromide and 1-bromohexane-d13 to form 2-octene-d13, which was subjected to an ene reaction with maleic anhydride to afford 2-octenylsuccinic anhydride-d13.