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(4H)-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(4H)-naphthalenones bearing an all-carbon benzylic quaternary stereocenter.