Tuning the basicity of synergic bimetallic reagents: switching the regioselectivity of the direct dimetalation of toluene from 2,5-to 3,5-positions

Meta-meta metalation: Remarkably, toluene can be directly dimanganated or dimagnesiated at the 3,5-positions using bimetallic bases with active Me3SiCH2 ligands (see scheme, blue). In contrast, n-butyl ligands lead to 2,5-metalation (red). tmp=2,2,6,6-tetramethylpiperidide.