RETRACTED: Direct synthesis of 1-naphthylamines enabled by 6-endo-dig cyclization strategy using copper catalysis (Retracted Article)

Here, we describe a facile approach for the synthesis of substituted 1-naphthylamines via three-component 6-endo-dig cyclization of terminal alkynes with 2-bromoaryl ketones, primary or secondary amines in water under Pd-free conditions. The Cu(I) catalytic system avoids a fundamental problem related to these substrates, which competitively evolve through 5-endo-dig cyclization pathways under metal catalysis. This unique performance unlocks a rapid access to a diverse 1-naphthylamines library that previously required longer synthetic routes. The synthetic potential of this method was further demonstrated by the gram-scale synthesis, and the mechanism study showed that the reaction experienced sequential halide exchange, imine-enamine tautomerization and 6-endo-dig cyclization.