1. The endocyclic restriction test: Oxygen transfer from N-sulfonyl oxaziridines to alkenes and fluorine from N-fluorosultams to carbanions. 2. Intra- and intermolecular kinetic isotope effects in directed lithiations

The transition state geometry for the transfer of oxygen from N-sulfonyl oxaziridines to alkenes and fluorine transfer from N-fluoro sultams to carbanions was investigated. In the former application of the endocyclic restriction test, a transition state model was developed, however, a model has not been constructed in the latter case. Although no transition state model has been constructed for the transfer of fluorine, the control experiments conducted indicate that this reaction is amenable to study using the endocyclic restriction test. The mechanism of hydrogen transfer from a benzylic or aryl carbon atom to organolithium reagents has been investigated by measuring intra- and intermolecular kinetic isotope effects. The results were more in line with a two-step mechanism where an organolithium base coordinates to the heteroatom of the directing group prior to the deprotonation step. These experiments underscore the inability of this method to quantify large isotope effects and the need to access the error of the measurements when comparing intra- and intermolecular kinetic isotope effects.