Conjugated Cyclotetraynes: Synthesis and Characterization

Cyclotetraynes presented in this thesis feature four conjugated triple bonds and an alkyl tether that completes the cyclic structure. This series of strained cyclotetraynes have been synthesized due to their synthetically challenging structures and to explore their unique physical properties as a function of ring strain. The Hay acetylenic homocoupling method and the Fritsch-Buttenberg-Wiechell rearrangement represent the key steps in obtaining these molecules. 13C NMR and UV-vis spectroscopies have been used to establish trends as function of ring strain and show, for example, that the more the strained the cycle is, the more deshielded the chemical shifts of the sp-hybridized carbon atoms. Herein, the synthesis and characterization of cyclic tetracycloalkynes 202-204 and one linear analogue 205 are discussed.