Lithiation/trapping of N-Boc piperazines and synthesis of the (–)-sparteine surrogate

This thesis describes some novel aspects of the s-BuLi mediated lithiation/trapping of N-Boc heterocycles, including a systematic investigation into the lithiation/trapping of N-Boc piperazines. Chapter 2 details an in situ ReactIR™ investigation into the time required for both the lithiation and trapping events of some commonly used N-Boc heterocycles. The remarkable difference in the time taken for trapping with some electrophiles is of particular note. The information garnered in this investigation was used to direct the racemic and asymmetric lithiation of N-Boc piperazines, as described in Chapters 3 and 4. A series of complications were encountered and overcome. The methodology culminated in the synthesis of enantiopure mono- and disubstituted N-Boc piperazines In Chapter 5, an investigation into the synthesis of the (–)-sparteine surrogate is reported. Two strategies are described: synthesis and classic resolution of racemic sparteine surrogate and the synthesis of enantiopure sparteien surrogate from commercially available precursors.