Abstract
Bergman cyclization is commonly used to produce highly reactive diradical intermediates that can be used in polymer chemistry and in the design of health benefitting drugs. For example, enediyne derived drugs can be used as potent DNA cleaving agents and anti-cancer agents to induce apoptosis. In search of new substrates that can produce reactive diradical intermediates we are interested in readily available diene-enones to examine their ability to undergo thermal cyclization. The synthesis of the diene-enone starts with an Aldol condensation of Benzaldehyde and 2’-iodoacetophenone to generate the enone portion. This was followed by a Suzuki coupling reaction, which replaced the iodo substituent with an alkene to make the diene-enone. Upon heating, four possible diradical cyclization products can form (C1- C6, C1-C7, C2-C6 and C2-C7) along with a potential Diels-Alder cycloaddition product. As these reaction are likely reversible, 1,4-cyclohexadiene is commonly added to quench the diradical intermediate for a ford the final product. The synthesis and thermal reactivity of the new diene-enone is highlighted below.