Pd-Catalyzed Regioselective Arylboration of Vinylarenes
作者:Kai Yang、Qiuling Song
DOI:10.1021/acs.orglett.6b02527
日期:2016.11.4
A palladium-catalyzed 1,2-arylboration of vinylarenes with aryldiazonium tetrafluoroborates and bis(pinacolato)diboron has been disclosed. It is reported for the first time that styrene derivatives can be successfully employed as good substrates for 1,2-arylboration of alkenes. Mechanistic studies suggest that no Pd–H reinsertion occurred under our standard conditions, which is the key for the success
Catalytically active Pd nanoparticles have been synthesized in water by a novel reduction of Pd(II) with a Fischer carbene complex where polyethylene glycol (PEG) was used as stabilizer. PEG molecules wrap around the nanoparticles to impart stability and prevent agglomeration, yet leave enough surface area available on the nanoparticle for catalytic activity. Our method is superior to others in terms of rapid generation and stabilization of Pd nanoparticles in water with a cheap, readily available PEG stabilizer. The size of the nanoparticles generated can be controlled by the concentration of PEG in water medium. The size decreased with the increase in the PEG: Pd ratio. This aqueous nano-sized I'd is a highly efficient catalyst for Suzuki, Heck, Sonogashira, and Stille reaction. Water is Used as the only solvent for the coupling reactions. (C) 2009 Elsevier Ltd. All rights reserved.
Cross-Coupling Catalysis by an Anionic Palladium Complex
Recent studies have shown that anionic palladium complexes are viable catalysts for a range of catalytic cross-coupling reactions. We present a one-step synthesis of the anionic “ligandless” palladium complex [NBu4][Pd(DMSO)Cl3] together with its crystal structure. This compound has been shown to be an active precatalyst in the Mizoroki–Heck reaction. Under Jeffery conditions, activated aryl chlorides