Electrophilic Cyclization of (Z)-Selenoenynes: Synthesis and Reactivity of 3-Iodoselenophenes
摘要:
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.
3-Iodoselenophene derivatives: a versatile substrate for Negishi cross-coupling reaction
作者:Ricardo F. Schumacher、Diego Alves、Ricardo Brandão、Cristina W. Nogueira、Gilson Zeni
DOI:10.1016/j.tetlet.2007.11.070
日期:2008.1
3-Iodoselenophene derivatives undergo a direct Negishi cross-coupling reaction with several organozinc compounds in the presence of a catalytic amount of Pd(PPh3)4 in THF at roomtemperature. This cross-coupling reaction proceeded cleanly under mild conditions and permitted the formation of polyaromatic compounds in good yields.