INVESTIGATION ON AMINO-HECK CYCLIZATION OF 1-(2-VINYLCYCLOHEXYL)KETONE DIETHYL PHOSPHINYLOXIMES

Upon the treatment with Pd(PPh3)4 and Et3N in DMF at 80 degrees C, a range of trans-1-(2-vinylcyclohexyl)-substituted ketone diethylphosphinyloximes underwent the cyclization in a 6-endo pathway to afford 1-substituted tetrahydroisoquinolines in varying yields. Among which, the reactions of the substrates bearing the saturated alkyl groups were severely competed by hydrolysis and/or Beckmann rearrangement, while these undesired side reactions could be suppressed by introducing a beta-aryl moiety possibly due to the stabilizing pi-pi stacking interactions between the phosphoryl and/or vinyl group and the aryl rings.