FeCl₃‑Mediated One-Pot Domino Reactions for the Synthesis of 9‑Aryl/9-Arylethynyl-2,3,4,9-tetrahydro‑1<i>H</i>‑xanthen-1-ones from Propargylic Amines/Diaryl Amines and 1,3-Cyclohexanediones

An efficient, environmentally friendly and one-pot route to new 9-aryl/9-arylethynyl-2,3,4,9-tetrahydro-1H-xanthen-1-one derivatives from inexpensive starting materials has been developed. This method proceeded by a domino nucleophilic-substitution/​intramolecular cyclization/​dehydration sequence of propargylic amines/diaryl amines and 1,3-cyclohexanediones under the promotion of FeCl3, which involved the formation of two new σ (C–C and C–O) bonds in a single operation for the construction of novel tetrahydroxanthene skeletons in 68–95% yields.