Isolation and characterisation of the mixed-metal alkyl amide [(TMEDA)Na(mu-Bu)(mu-TMP)Mg(TMP)], an unexpected chelate-trapped intermediate in the formation of inverse crowns.

Only two-fold amination occurs when 3 molar equivalents of TMPH are offered to a 1:1 BuNa-Bu2Mg mixture; adding TMEDA gives the mixed alkyl amide [(TMEDA)Na(mu-Bu)(mu-TMP)Mg(TMP)], which itself affords the phenyl-bridged analogue when reacted with benzene.