Presenters: Cassidy Ross
Authors: Tanner James, Cassidy Ross, Nathan Werner
Faculty Advisor: Nathan Werner
Institution: Southern Utah University
The synthesis of (E)-stilbene through a palladium-catalyzed cross-coupling reaction heated by microwave irradiation was studied. (E)-stilbene can be synthesized in moderate to good yields from (E)-2-phenylethenylboronic acid pinacol ester and aryl bromides. Heating by microwave irradiation can improve the yield of the chemical reactions when compared to traditional conduction heating. The effects microwave irradiation had on the reaction variables of solvent and ligand on the isolated yield and alkene geometry of the desired products was examined. These findings were compared to reactions that used traditional conduction heating found in literature. The optimal conditions for cross-coupling reactions heated under microwave irradiation were elucidated. Interestingly, these optimized microwave reaction conditions used the same reaction solvent and temperature as the reaction heated by conduction. However, microwave irradiation decreased the overall reaction time. In addition, the ligand triphenylphosphine was found to produce high yields with aryl bromides bearing both electron withdrawing and electron donating substituents which was not observed in the reaction heated by conduction. The ligandt-Bu3PHBF4was required in the reactions heated by conduction to produce similar yields of the (E)-stilbene derivatives that bore electron donating substituents.