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Directed Iron-Catalyzed ortho-Alkylation and Arylation: Toward the Stereoselective Catalytic Synthesis of 1,2-Disubstituted Planar-Chiral Ferrocene Derivatives
journal contribution
posted on 2017-12-14, 19:06 authored by David Schmiel, Holger ButenschönThe 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%.