Visible-Light-Mediated Addition of Phenacyl Bromides onto Cyclopropenes

Visible-light-promoted addition of α-bromoacetophenones onto the cyclopropene π-system in the presence of the fac -Ir(ppy) 3 catalyst was shown to afford the corresponding 1(4 H )-naphthalenones. The syn -carboarylation of the cyclopropene is followed by a cyclopropane ring opening under the basic conditions, allowing the formation of two C–C bonds and the generation of 1(4 H )-naphthalenones bearing an all-carbon benzylic quaternary stereocenter.