Electrophilic cyclization of 2-chalcogenealkynylanisoles: versatile access to 2-chalcogen-benzo[b]furans.
An efficient synthesis of 2-chalcogen-3-substituted-benzo[b]furan compounds has been accomplished via electrophilic cyclization reaction of 2-chalcogenealkynyl anisoles using I(2), ICl, Br(2), and PhSeBr as electrophile sources. The product distributions were strongly dependent on the nature of substituents in the aromatic ring of anisole and on the chalcogen atom directly bonded to the triple bond. The 2-chalcogen-3-iodo-benzo[b]furans obtained smoothly underwent conversion to more complex structures of benzo[b]furan derivatives via palladium- or copper-catalyzed cross-coupling reaction with thiols, diphenyl diselenides, and zincates.
Manarin
Flávia
F
Laboratório de Síntese, Reatividade, Avaliação Farmacológica e Toxicológica de Organocalcogênios, CCNE, UFSM, Santa Maria, Rio Grande do Sul, Brazil 97105-900.
Roehrs
Juliano A
JA
Gay
Rafaela Mozzaquatro
RM
Brandão
Ricardo
R
Menezes
Paulo H
PH
Nogueira
Cristina W
CW
Zeni
Gilson
G
D000840:Anisoles / Q000737:chemistry*; D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D015394:Molecular Structure; D013237:Stereoisomerism
D000840:Anisoles; D001572:Benzofurans