Synthesis 2009(23): 4001-4009  
DOI: 10.1055/s-0029-1217041
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of 3-Alkynyl-2-(methylsulfanyl)benzo[b]furans via Sonogashira Cross-Coupling of 3-Iodo-2-(methylsulfanyl)benzo[b]furans with Terminal Alkynes

Flávia Manarin, Juliano A. Roehrs, Ricardo Brandão, Cristina W. Nogueira, Gilson Zeni*
Laboratório de Síntese, Reatividade, Avaliação Farmacológica e Toxicológica de Organocalcogênios, CCNE, UFSM, Santa Maria, Rio Grande do Sul, CEP 97105-900, Brazil
Fax: +55(55)32208978; e-Mail: gzeni@pq.cnpq.br;
Further Information

Publication History

Received 27 April 2009
Publication Date:
12 October 2009 (online)

Abstract

3-Alkynyl-2-(methylsulfanyl)benzo[b]furans were readily prepared under mild reaction conditions by palladium-catalyzed cross-coupling of 3-iodo-2-(methylsulfanyl)benzo[b]furans with a variety of terminal alkynes. The reaction was performed with propargyl alcohols, protected propargyl alcohols, as well as alkyl and aryl terminal alkynes. In addition, the 3-alkynylbenzo[b]furans obtained were readily transformed into more complex products using the hydrotelluration reaction, which furnished the desired vinylic tellurides in good yields. Moreover, using a copper-catalyzed homocoupling reaction, we were able to convert a 3-alkynylbenzo[b]furan into a symmetric diyne in good yield.