A new method for the preparation of bicyclo[5.3.0]decane ring systems: Controlling stereochemistry at the bridgehead

The rhodium catalyzed functionalization of activated olefins utilizing nucleophiles generated in situ has been examined. The reduction of benzyl- and allyl-halides afforded substrates capable of transmetalation, but proved to be more reactive towards direct addition to the enone substrates under examined reaction conditions. Group 10 metals were also examined in the desired transformation, in hopes of enabling direct oxidative addition into the substrates that required activation under the rhodium catalyzed conditions. While the general Heck reaction proved successful, ?-hydride elimination proved to be the principal reaction path for the generated palladium enolates.