APPLICATION OF THE ORTHO-LITHIATION-CYCLIZATION STRATEGY TO N-BENZYLAMINE AND N-PHENETHYLAMINE DERIVATIVES

The ortho-lithiation-cyclization of iodinated N,N-diacylphenethylamine s provides a convenient method for the preparation of 2-(2-acetoamidoe thyl)acetophenones and 2-(2-benzamidoethyl)benzophenones, which could be easily transformed into dihydroisoquinolines. By contrast, the N-et hylamino, N-acetyl-amino, and N-trimethylsilylamino moieties studied a s ortho-directing groups provide poor assistance to the metalation of N-benzyl- and N-phenethylamines and the corresponding isoindolone or i soquinolone derivatives are obtained in low yields.