in tetrahydrofuran byproducts: KCl, C16H22; to slurry of MnCl2 (1.71 mmol) in THF at -78°C added (dmCh)K (3.42 mmol) from solid addn. funnel over 3 h (alternativly, THF soln. of (dmCh)K added dropwise over 3 h), stirred for 4 h, allowed to warm to 25°C, stirred addnl. for 12 h; THF removed, pentane added, filtered, pentane removed;

in tetrahydrofuran under Ar; evapn. of solvent, extn. (pentane), pentane evapd. off: (Me2C6H5)2;