Özet:
Novel 1,3-dialkylimidazolidinium, 1,3-dialkyl-3,4,5,6- tetrahydropyrimidinium, and 1,3-dialkyl-1 H-4,5,6,7-tetrahydrodiazepinium hexafluo-rophosphates (1a-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. © 2008 Wiley Periodicals, Inc.