Directed Iron-Catalyzed ortho-Alkylation and Arylation: Toward the Stereoselective Catalytic Synthesis of 1,2-Disubstituted Planar-Chiral Ferrocene Derivatives

The iron-catalyzed directed ortho-functionalization of arenes developed to an important method in the field of C-H activation. On the other hand, the iron-catalyzed ortho-functionalization of ferrocenes bearing ortho-directing groups (ODGs) has scarcely been investigated. Herein we present the iron-catalyzed ortho-alkylation and -arylation of ODG-substituted ferrocenes bearing a bidentate ODG with the formation of racemic 1,2-disubstituted ferrocenes in up to 94% yield. The approach toward an enantioselective iron-catalyzed C-H activation resulted in an ortho-phenylation with a promising enantiomeric excess of 46%. The first iron-catalyzed diastereoselective ortho-methylation gave an excellent diastereomeric excess of >= 99%.