(C(C6H5)2(OH))2 in dichloromethane byproducts: (C6H5)2CO, H2NCOC6H3(CF3)2; under Ar; a mixt. of the bismuthane, 1,1,2,2-tetraphenylethanediol and CH2Cl2 was stirred at 25°C for 24 h; the solvent was evapd. under vac., the oily residue was chromd. on silica gel (hexane/CH3CH2O2CCH3);