anhydrous conditions;

in dichloromethane byproducts: AgCl; to a suspn. of Ag-salt in CH2Cl2 was added dropwise a soln. of B-complex in CH2Cl2 with stirring at -78°C, stirred for 1 h under N2; AgCl was removed, solvent stripped from filtrate at room temp., ppt. was kept for 2 h under high vac.; elem. anal.;