Bromine-Position-Controlled Palladium-Catalyzed Divergent C-H Annulation of Chalcones with o-Halobenzoic Acids.

Abstract

By tuning the bromine substituent position in chalcones, we herein developed a palladium-catalyzed divergent C-H activation/decarboxylative cyclization with o-halobenzoic acids. Substrates bearing the bromine at the ortho position of the styrenyl moiety, namely (E)-1-(2-bromophenyl)-3-phenylprop-2-en-1-ones, undergo a Heck cyclization, oxidative dehydrogenation, C-H activation, and decarboxylation cascade to afford phenanthrene-fused indanones. In addition, the isomeric (E)-3-(2-bromophenyl)-1-phenylprop-2-en-1-ones selectively deliver 9-acylphenanthrenes. This protocol features excellent regioselectivity and broad substrate compatibility.