Palladium-Catalyzed Cyclization of<i>N</i>-<i>n</i>-Butyl,<i>N</i>-(<i>o</i>-Iodobenzyl)-3-butenamides: Six- versus Seven- and Eight-membered Ring Formation
palladium-catalyzed annulation of N-n-butyl, N-(o-iodobenzyl)-3-butenamides 1 can be dramatically varied by addition of water to the reaction mixture. In anhydrous DMF 1 lead to 6-membered ring formation, while in aqueous DMF 7/8-membered rings were formed. The water effect was also observed in MeCN and THF.