title: Electrophilic cyclization of (Z)-selenoenynes: synthesis and reactivity of 3-iodoselenophenes.
abstract: We present here our results of the electrophilic cyclization reaction of (Z)-selenoenynes with different electrophiles such as I(2), ICl, PhSeBr, and PhSeCl. The cyclization reaction proceeded cleanly under mild reaction conditions, and 3-substituted selenophenes were formed in moderate to excellent yields. We observed that the nature of solvent and structure of (Z)-selenoenyne were important to the cyclization reaction. In addition, the obtained 3-iodoselenophenes were readily transformed to more complex products using a metal-halogen exchange reaction with n-BuLi and trapping the intermediate formed with aldehydes, furnishing the desired secondary alcohols in good yields. Conversely, using the palladium or copper catalyzed cross-coupling reactions with terminal alkynes or alkyl alcohols, we were able to convert 3-iodoselenophene to Sonogashira or Ullmann type products, respectively, in good yields.
authors: Laboratório de Síntese, Reatividade, Avaliação Farmacológica e Toxicológica de Organocalcogênios, CCNE, UFSM, Santa Maria, Rio Grande do Sul, Brazil, 97105-900.
authors: Diego
authors: D
authors: Alves
authors: Cristiane
authors: C
authors: Luchese
authors: Cristina W
authors: CW
authors: Nogueira
authors: Gilson
authors: G
authors: Zeni
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D003500:Cyclization; D004583:Electrons; D007455:Iodine / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry; D015394:Molecular Structure; D016566:Organoselenium Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000447:Aldehydes; D016566:Organoselenium Compounds; D007455:Iodine; D008094:Lithium