Novel 1,3-dialkylimidazolidinium, 1,3-dialkyl-3,4,5,6-tetrahydropyrimidinium, and 1,3-dialkyl-1H-4,5,6,7-tetrahydrodiazepinium hexafluorophosphates (la-c, 2a-c) as N-heterocyclic carbene precursors have been synthesized and characterized. The incorporation of saturated N-heterocyclic carbenes into palladium precatalysts gives high-catalyst activity in the Heck coupling of aryl bromide substrates in aqueous media. The complexes were generated in the presence of Pd(OAC)(2) by in situ deprotonation of 1,3-dialkylazolinium salts 1, 2. (C) 2008 Wiley Periodicals, Inc.
C1 [Oezdemir, Ismail; Guerbuez, Nevin; Goek, Yetkin] Inonu Univ, Dept Chem, Fac Sci & Art, TR-44280 Malatya, Turkey.
[Cetinkaya, Bekir] Ege Univ, Dept Chem, Fac Sci, TR-35100 Bornova, Turkey.