benzofurans and acrylic-acid

Migratory cycloisomerization using transition metal catalyst is useful for synthesizing substituted heterocyclic compounds. We achieved palladium-catalyzed migratory cycloisomerization of 3-o-alkynylphenoxy acrylic acid ester derivatives to give 2,3-disubstituted benzofurans. Although there are several reports of benzofuran synthesis with palladium-catalyzed migratory cycloisomerization, migratory groups are limited to allyl and propargyl groups. This report is the first example of benzofuran synthesis with palladium-catalyzed cycloisomerization of C(sp

Topics: Benzofurans; Catalysis; Heterocyclic Compounds; Palladium

In this paper, a novel and applicable synthesis of benzofurans from commercially available phenols and propiolate through the direct oxidative cyclization has been developed. In the presence of Pd(OAc)(2)/PPh(3) and CF(3)CO(2)Ag, (E)-type 3-phenoxyacrylates underwent reaction smoothly to generate the corresponding benzofurans in good yields in benzene at 110 °C under the air pressure. In addition, this transformation of phenols into benzofurans can also be carried out in one pot. The process was simple and efficient. A tentative mechanism of palladium-catalyzed oxidative cyclization of 3-phenoxyacrylates was proposed.

Topics: Acrylates; Benzofurans; Catalysis; Cyclization; Oxidation-Reduction; Palladium; Phenols

Acrylic acids and alanines substituted with heteroaryl groups at the beta-position were synthesized and spectroscopically characterized (UV, HRMS, (1)H NMR, and (13)C NMR spectroscopy). The heteroaryl groups were furanyl, thiophenyl, benzofuranyl, and benzothiophenyl and contained the alanyl side chains either at the 2- or 3-positions. While the former are good substrates for phenylalanine ammonia-lyase (PAL), the latter compounds are inhibitors. Exceptions are thiophen-3-yl-alanine, a moderate substrate and furan-3-yl-alanine, which is inert. Possible reasons for these exceptions are discussed. Starting from racemic heteroaryl-2-alanines their D-enantiomers were prepared by using a stereodestructive procedure. From the heteroaryl-2-acrylates, the L-enantiomers of the heteroaryl-2-alanines were prepared at high ammonia concentration. These results can be best explained by a Friedel-Crafts-type electrophilic attack at the aromatic part of the substrates as the initial step of the PAL reaction.

Topics: Acrylates; Alanine; Benzofurans; Catalysis; Drug Interactions; Furans; Petroselinum; Phenylalanine Ammonia-Lyase; Spectrum Analysis; Substrate Specificity; Thiophenes