2011 Theses Doctoral

Part 1: Progress Toward the Total Synthesis of Platensimycin. Part 2: Aromatic Ions: Carbon-Based Nucleofuges and Chiral Cyclopropenones and Formamides

Fisher, Ethan Lawrence

This thesis describes progress toward to the total synthesis of the natural product platensimycin, the development of proficient carbon nucleofuges for the Tsuji-Trost allylation, and the use of chiral cyclopropenones and formamides for the kinetic resolution of alcohols by chlorodehydration.

The first chapter describes efforts in the total synthesis of platensimycin. The synthesis attempted to use a thermal rearrangement, through a biradical intermediate, and then radical induced [3+2] cycloaddition between a vinyl cyclopropane and pendant olefin to create the core of platensimycin. A revised strategy was employed using a palladium(0) catalyzed Heck cascade and palladium(II) catalyzed alkoxypalladation.

The second chapter describes the development of a carbon-based nucleofuge. A substituted cyclopentadienyl anion served as a competent leaving group in the Tsuji-Trost allylation. Various substrates were examined including carbon and nitrogen nucleophiles. The reaction mechanism with nitrogen nucleophiles is studied. The third chapter describes the synthesis of chiral cyclopropenones and their use in the kinetic resolution of alcohols by chlorodehydration. Chiral formamides are also studied for their use in chlorodehydration. Transition states for enantiodifferentiation are proposed.