• Undergoes pinacol rearrangement on treatment with sulfuric acid to give ɑɑɑ-triphenylacetophenone in high yield. With the superacidic triflic acid, however, dehydrative cyclization to 9,10-diphenylphenanthrene occurs: Synthesis, 321 (1996); Org. Synth., 76, 294 (1998). The same pruduct is obtained on treatment of ɑɑɑ-triphenylacetophenone or tetraphenyloxirane with superacid mixtures: J. Org. Chem., 62, 6666 (1997).