Syntheses of trifluoroethylated unsymmetrical 1,3-diynes by using 1,1-dichloro-2,2,2-trifluoroethane

摘要

Copper-mediated reaction of terminal 1,3-diynes with 1,1-dichloro-2,2,2-trifluoroethane (CF3CHCl2) using ethanolamine as ligand gave trifluoroethylated unsymmetrical 1,3-diynes in moderate to good yields. The reaction were carried out under mild conditions, and were easy to operate. Aryl groups with weak electron-withdrawing group or electron-donating group, and alkyl substitutents at terminal 1,3-diynes were tolerated. Synthesis of a trifluoroethylated conjugated triyne by using this method was demonstrated. Further transformation of the trifluoroethylated unsymmetrical 1,3-diyne to provide trifluoroethyl-substituted 1,2,3-triazole and isoxazole as application examples were successfully realized. (C) 2016 Elsevier Ltd. All Tights reserved.