Electrophilic ipso-Halocyclization of N-Arylpropynamides with Polyfluoroalkyl Alcohols: Selective Synthesis of 8-(Polyfluoroalkoxy)azaspiro[4.5]trienes - Wang, Zhi-Qiang; Tang, Bo-Xiao; Zhang, Hong-Ping; Wang, Feng; Li, Jin-Heng (Synthesis, 2009)