930101-04-5Relevant articles and documents
Easy access to esters with a benzylic quaternary carbon center from diallyl malonates by palladium-catalyzed decarboxylative allylation
Imao, Daisuke,Itoi, Akihiro,Yamazaki, Asako,Shirakura, Masamichi,Ohtoshi, Ryota,Ogata, Kenta,Ohmori, Yohki,Ohta, Tetsuo,Ito, Yoshihiko
, p. 1652 - 1658 (2007/10/03)
Diallyl 2-alkyl-2-arylmalonates underwent palladium-catalyzed decarboxylative allylation quickly under mild conditions. In contrast, no reaction took place with diallyl 2,2-dialkylmalonates under the same conditions. Electron-donating phosphine ligands were found to be vital for this reaction. Most of the solvents used did not affect the catalytic cycle. Catalysis in [bmim][BF4], a well-known ionic liquid, was inhibited as a result of formation of a hydrogen bond between a carboxylate anion and a [bmim] + cation; however, the reaction in [bdmim][BF4], in which the acidic proton of [bmim][BF4] was replaced with a methyl group, proceeded smoothly. The catalytic mechanism was investigated using a tetradeuterated substrate and an enzymatically synthesized enantio-enriched allyl methyl 2-methyl-2-phenylmalonate. Even the electron-deficient phosphite ligand was found to be active for catalysis of diallyl 2-methyl-2-(2- or 4-nitrophenyl)malonates.
