The synthesis of the optically-active sodium salt of tetrakis(4,5,6,7-tetrahydro-7,8,8-trimethyl-2H-4,7-methanoindazolyl)borate, [NaB-(camphpz)4] (1) is reported. Cu-based in situ catalysts containing [NaB(camphpz)4] give an enantiomeric excess of up to 62% in the enantioselective cyclopropanation of styrene with ethyl diazoacetate.