1,3-Bis(trifluoromethyl)prop-2-ene 1-Iminium Salts: Reactions with Alkoxybenzenes and Anilines

Abstract

1,3-Bis(trifluoromethyl)prop-2-ene 1-iminium triflate salts were prepared for the first time and some synthetic applications as 1,3-biselectrophilic building blocks were established. They were found to react with dimethoxybenzenes or methylene-1,2-dioxybenzenes to furnish vinylogous trifluoroacetylaton products (4-aryl-1,1,1,5,5,5-hexafluoropent-3-en-2-ones) and 1-dialkylamino-1,3-bis(trifluoromethyl)-1H-indenes. With aniline and ring-substituted anilines, 2,4-bis(trifluoromethyl)quinolines were formed. An unusual 4H-pyran, formally a condensation product of the N,N-dimethyl-1,3-bis(trifluoromethyl)prop-2-en-1-iminium ion and its enaminone precursor, is also reported.