Nm. Williamson et al., AN IMPROVED SYNTHESIS OF 2,2-DISUBSTITUTED-1,2-DIHYDROQUINOLINES AND THEIR CONVERSION TO 3-CHLORO-2,2-DISUBSTITUTED-TETRAHYDROQUINOLINES, Tetrahedron letters, 36(42), 1995, pp. 7721-7724
N-(1,1-disubstitutedpropargyl)anilines can be cyclised to 2,2-disubsti
tuted-12-dihydroquinolines by refluxing them in toluene containing cup
rous chloride. Electron donating groups in the para position of the ri
ng enhance the reaction rare and electron withdrawing groups markedly
decrease the rare. The derived N-acetyldihydroquinolines can be cis di
chlorinated and selectively monodechlorinated at the benzylic position
to produce 3-chlorotetrahydroquinolines.