Ferrocenylindium reagents in palladium‐catalyzed cross‐coupling reactions: asymmetric synthesis of planar chiral 2‐aryl oxazolyl and sulfinyl ferrocenes

Abstract

[Abstract] The preparation of ferrocenylindium species and palladium‐catalyzed cross-coupling reactions for the synthesis of monosubstituted and planar chiral 1,2‐disubstituted ferrocenes is described. Triferrocenylindium reagents (Fc3In) are efficiently prepared in a one‐pot procedure from ferrocenes by lithiation and transmetallation to indium using InCl3. The palladium‐catalyzed cross‐coupling reactions of Fc3In (40 mol%) with a variety of organic electrophiles (aryl, heteroaryl, benzyl, alkenyl and acyl halides) in THF at 80 °C overnight provided a wide variety of monosubstituted ferrocenes in good to excellent yields. This methodology allowed the stereoselective synthesis of planar chiral 2‐aryl‐1 oxazolylferrocenes and 2‐aryl‐1‐sulfinylferrocenes, which are of interest in asymmetric catalysis.