Synthesis and reactivity of arylgold(III) complexes from aromatic hydrocarbons via C-H bond activation

The reactions of anhydrous gold(III) chloride [AuCl3](2) with aromatic hydr ocarbons (ArH) such as benzene, toluene, xylenes, mesitylene, cumene, metho xybenzene and chlorobenzene, and the following treatment with 2,6-lutidine (lut) gave stable arylgold(iii) complexes [AuArCl2(lut)]. These auration re actions proceeded heterogeneously in hexane and homogeneously in diethyl et her. The H-1 NMR spectra of the arylgold(iii) complexes revealed that aurat ions towards aromatic compounds take place regiospecifically at the positio n with higher electron density and with less steric hindrances. The trans c onfiguration of the arylgold(iii) complexes was established by means of the ir far-IR spectra and confirmed for [Au(2,5-Me2C6H3)Cl-2(lut)] by its singl e-crystal X-ray structure. The reactions of [AuArCl2(lut)] (Ar = phenyl, 2, 5-xylyl) with a terminal alkyne, phenyacetylene (HO=CPh), afforded arylated phenylacetylenes ArC=CPh.