Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The scope of the Heck arylation of cyclic and acyclic enol ethers with arenediazonium salts was evaluated. Arylation of 2,3-dihydrofuran yielded 2-aryl-2,5-dihydrofurans as the major adducts (>99:1) except when using n-Bu(4)NHSO(4) as additive or 4-NO(2)PhN(2)BF(4) as arenediazonium salt. 2,3-Dihydropyran provided mixtures of the three possible isomeric Heck adducts. Arylation of n-butylvinylether with arenediazonium bearing electron-donating groups resulted in substituted acetophenones as almost exclusive products in good overall yields, Substituted 4H-chromenes provided 2-aryl-2H-chromenes in moderate yield when applying the Pd(OAc)(2)/2,6-di-t-butyl-4-methylpyridine catalytic system, which were applied in the synthesis of flavonoids. (C) 2009 Elsevier Ltd. All rights reserved.501112221225Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)