Synthesis of symmetrically and unsymmetrically 3,5-dimethylbenzyl-substituted 1,1′-ferrocene diamines

1,1′-Ferrocene diamides have shown remarkable efficacy as supporting ligands for electrophilic metal centers. While different substituents have been used, most ferrocene diamines are employed as dianionic precursors, thus limiting the possible scope and reactivity of these metal complexes. The use of a 3,5-dimethylbenzyl (xylyl) substituent allowed the successful synthesis of tri- and tetra-substituted ferrocene 1,1′-diamines, providing monoanionic and neutral pro-ligands. In addition, an unsymmetrically disubstituted 1,1′-ferrocene diamine was obtained containing both the 3,5-dimethylbenzyl and t-butyldimethylsilyl substituents.