M. Paz Muñoz

Palladacycles as Precatalysts in Heck and Cross-Coupling Reactions

A variety of palladacycles are shown to catalyze Heck alkenylations with similar efficiencies. The new oxapalladacycle 1 was shown to insert and transmetalate under mild conditions with n-butyl acrylate and vinyltributylstannane, respectively. This palladacycle acts as an active (pre)catalyst for cross-coupling and Heck reactions.

INTRAMOLECULAR REACTIONS OF ALKYNES WITH ALKENES CATALYZED BY PLATINUM AND GOLD

Two major pathways are followed in the reaction of alkenes with alkynes catalyzed by electrophilic transition metals. If the metal coordinates the alkyne and the alkene, an oxidative cyclometallation can ensue to give a metallacyclopentene, which usually evolves by β-hydrogen elimination (Alder-ene cycloisomerization). Alternatively, the selective coordination of the metal to the alkyne promotes an attack of the alkene (usually anti) to give cyclopropyl metal carbenes.