n-BuLi in diethyl ether; hexane (Ar); Schlenk glassware; soln. of n-BuLi in hexane was added to soln. ofisomer mixt. of ligand in ether at room temp.; mixt. was stirred for 12 h; cooled to -40°C; Mn complex was added; soln. was stirred at - 40°C for 1 h; solvent evapd. (vac.); hexane added; refluxed for 3 h; concd.; chromd. (silica gel, hexane); evapd. (vac.); dissolved in CH2Cl2; CF3CO2H added; stirred for 15 min; filtered; filtrate evapd. (vac.); elem. anal.;