Methodology for the preparation of isoquinoline derivatives fromN-(tert-butoxycarbonyl)-2-methylbenzylamines (1) was developed. Conversion of1to the dilithio species followed by condensation with DMF afforded Boc-3-hydroxy-1,2,3,4-tetrahydroisoquinolines3, which could be dehydrated to 1,2-dihydroisoquinolines4. Hydrogenation of dihydro compounds4afforded the corresponding tetrahydroisoquinolines5. Treatment of the dilithio species from1withN-methoxy-N-methylamides afforded ketones14, which were converted to 3-substituted dihydro-isoquinoline15, tetrahydroisoquinolines (16,17), or isoquinolines (20).