The reaction of 2-fluoroalkyl-1-iodoethylenes with arylamines: a facile method for the synthesis of fluoroalkylated quinolines and enaminoketones

The reaction of 2-fluoroalkyl-1-iodoethylenes with arylamines () and the subsequent acid promoted transformation of the products were described. In the presence of ZnCl2 and triethylamine, reacted readily with various p-substituted anilines in HMPA under a vacuum of 60–70 mmHg to give the corresponding enaminoaldehydes () as a mixture of E- and Z-isomers. Cyclization of , without further purification in refluxing toluene, catalyzed by strong acids such as p-toluene sulfonic acid and trifluoromethanesulfonic acid gave 2-fluoroalkylquinolines () in good yields, while fluoroalkylated enaminoketones () were obtained predominantly when was treated with acids in aqueous THF solution. A possible mechanism was proposed for the formation of and .