Cross-coupling reactions: synthesis and photoactivity of enediynes

Abstract

The syntheses of a number of photoactive enediynes using the Sonogashira Coupling reaction are described. Alkynes with different characteristics were coupled to 2-bromoiodobenzene to yield the desired drugs. The enediyne’s functionality and their ability to undergo the Bergman Cyclization reaction is of interest given that a variety of naturally occurring and few synthetically produced compounds containing this unit demonstrate the ability to cleave DNA. The compounds were tested against human alveolar type 11-epithelial A549 cancer cells and the non-cancer cell line H9c2 and it was found that in the presence of light, they showed an enhanced ability to increase cell death. The enediyne with electron withdrawing functionality resulted in the greatest increase in cell death. In addition, an independent study on the direct arylation of heteroaromatic arenes with benzene was undertaken. In this study, substituted furans were treated under palladium-catalyzed conditions in the presence of benzene to synthesize biaryl compounds from unactivated starting materials. The presence of the electron with drawing aldehyde resulted in best yield of cross-coupling product.