HYDRAZINE-MEDIATED CARBONYL-OLEFIN METATHESIS: ANALYSIS OF HYDRAZINE STRUCTURES, RING-CLOSING REACTIONS, AND RING-OPENING REACTIONS
For years, the Lambert group has studied and exploited the use of hydrazines for carbonyl-olefin metathesis (COM). In trying to extend the capabilities of hydrazines, challenges have been identified that need to be addressed. This dissertation takes a closer look into the COM systems in addition to changes in the hydrazine system to identify these challenges, proved insights and propose potential solutions that could facilitate further developments. Chapter 1 of this dissertation introduces methods used for COM transformations. Chapter 2 focuses on the synthesis of 2,3-dihydrobenzoxepines via hydrazine-catalyzed ring-closing COM (RCCOM). The analysis of these reactions identifies problems of both substrate and hydrazine stability. Using 20 mol% of the [2.2.1] hydrazine, the product was obtained in 55% yield. Chapter 3 focuses on the analysis of norbornene reactivity as it pertains to ring-opening metathesis polymerization (ROMP) using hydrazines. Key to this discussion was the identification of the decomposition of our hydrazine salt and its replacement. Additionally, the analysis of the reaction between hydrazine and norbornene exposes a potential obstacle for efficient catalysis moving forward. Chapter 4 investigates the ring-opening COM (ROCOM) of cyclooctenes, with an investigation into the cyclic olefins that are tolerated with hydrazines and revels problematic steps. Chapter 5 presents hydrazines that were prepared and tested with various COM reactions, discussing the findings and what conclusions can be suggested from the results.