A New Class of Substrates for the Nucleophilic 5-endo-trig Cyclization, 1-Trifluoromethylvinyl Compounds: Syntheses of Indoline and Pyrrolidine Derivatives

Disfavored 5-endo-trig cyclizations were achieved in 1-trifluoromethylvinyl compounds with a sulfonamido group via (i) intramolecular SN2ʹ reaction with loss of a fluoride ion or (ii) intramolecular addition to the vinylic group. These reactions provided indoline and pyrrolidine derivatives bearing fluorinated one-carbon units such as difluoromethylene and trifluoromethyl groups.