Palladium-catalyzed cyclization of N-n-butyl, N-(o-iodobenzyl)-3-butenamides: Six- versus seven- and eight-membered ring formation

摘要

The regiochemistry of the 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. [References: 13]