Pd Nanoparticles-catalyzed Stereospecific Allyl-Aryl Coupling Reactions

Pd nanoparticles catalyzed Suzuki-Miyaura cross coupling reactionin water has been reported by many groups through both homogenousand heterogenous catalysis. This reaction is one of the most influentialsynthetic methods for preparing biaryl compounds. However, few reportsin Suzuki-Miyaura cross coupling focus on synthesizing allyl-arylcompounds catalyzed by Pd nanoparticles in water.We first present the practical and greener process for thestereospecific cross coupling of secondary allylic carbonates witharylboronic acids. In the reaction the catalyst turn into Pd nanoparticleswithout any ligands or additional stabilizer in water, accomplishingallyl-aryl coupling compounds in high isolated yields with completechemo-, regio-, E/Z selectivities and excellent stereospecifities. The insitu generated Pd nanopariticles showed extraordinary catalytic activity(s/c up to5000) even for the allyl-aryl coupling reaction of easilyeliminated allylic carbonates in water at room temperature. We apply thismethodology in the asymmetric synthesis of1,5-diene. Our studies effectively extend the scope of Pd nanoparticlescatalyzed Suzuki-Miyaura coupling reactions in water and provide agreen protocol for stereospecific allyl-aryl coupling..