Iodocyclization of o?Alkynylbenzamides Revisited: Formation of Isobenzofuran-1(3H)?imines and 1H?Isochromen-1-imines Instead of Lactams

摘要

The iodocyclization of o-alkynylbenzamidesnwith various electrophiles has been reported to yield five- ornsix-membered lactams by nucleophilic attack of the amidennitrogen onto the triple bond. While the formation of annisobenzofuran-1(3H)-imine with two bulky substituents undernLarock conditions was initially attributed to steric hindrance,nwe found out that cyclization via the amide oxygen is the rulenrather than the exception. Thus, the structures of the productsnreported in the literature need to be revised.