General and Selective Head-to-Head Dimerization of Terminal Alkynes Proceeding via Hydropalladation Pathway
作者:Claire Jahier、Olga V. Zatolochnaya、Nickolay V. Zvyagintsev、Valentine P. Ananikov、Vladimir Gevorgyan
DOI:10.1021/ol3010936
日期:2012.6.1
A general highly regio- and stereoselective palladium-catalyzed head-to-headdimerization reaction of terminal acetylenes is presented. This methodology allows for the efficient synthesis of a variety of 1,4-enynes as single E stereoisomers. Computational studies reveal that this dimerization reaction proceeds via the hydropalladation pathway.
E-conjugated enynes bearing an acetal function on the allylic or the homoallylic position or/and on the propargylic or the homopropargylic position were conveniently obtained at room temperature in DMF via cross coupling of the corresponding vinyltins with 1-bromoalk-1-ynes in the or Pd(II) catalysts.