The aims of this proposal are to develop new chemistry for the synthesis of beta-lactams, functionalized pyrrolidines and substituted piperidines which will have applicability in the formation of beta-lactam antibiotics and alkaloids. This work will seek to develop innovative ways of fusing five and six membered rings to the azetidinone framework in order to form products related to the natural beta-lactam antibiotics, as well as novel systems containing oxygen and nitrogen atoms. We will focus on functional group aggregates of particularly high reactivity such as vicinal tricarbonyl and units cyclopropanone precursors, and will explore the reactivity of molecules in which vinyl 1,2,3-tricarbonyl functions are assembled. These dielectrophiles show particular promise as precursors of functionalized pyrrolidine derivatives, which are promising as intermediates in alkaloid synthesis. In another phase of our work we will study the imino epoxide rearrangement as a pathway to the synthesis of piperidine alkaloids with a high degree of stereochemical control.