Ring-closing olefin metathesis of 2,2'-divinylbiphenyls: A novel and general approach to phenanthrenes

The ring-closing olefin metathesis (RCM) of 2,2'-divinylbiphenyls, using a second-generation RCM ruthenium-based catalyst, leads to differently substituted phenanthrenes in quantitative yield under very mild reaction conditions, independent of both nature and position of the groups present on the biphenyl moiety.