Application of the ortho‐lithiation‐cyclization strategy to N‐benzyl‐and N‐phenethylamine derivatives

The ortho‐lithiation‐cyclization of iodinated N,N‐diacylphenethylamines provides a convenient method for the preparation of 2‐(2‐acetoamidoethyl)acetophenones and 2‐(2‐benzamidoethyl)benzophenones, which could be easily transformed into dihydroisoquinolines. By contrast, the N‐ethylamino, N‐acetylamino, and N‐trimethylsilylamino moieties studied as ortho‐directing groups provide poor assistance to the metalation of N‐benzyl‐ and N‐phenemylamines and the corresponding isoindolone or isoquinolone derivatives are obtained in low yields.