Abstract
This account describes Cp*CoIII-catalyzed C–H functionalization reactions developed in our group between 2013 and 2018. Cp*CoIII catalysts not only serve as inexpensive alternatives to Cp*RhIII catalysts but also exhibit unique reactivity and selectivity in several transformations. In the latter part of this review, we introduce catalytic asymmetric C–H functionalization reactions using achiral RhIII or CoIII catalysts with chiral disulfonates or carboxylic acids as external chiral sources.
1 Introduction and Overview
2 Cp*CoIII-Catalyzed C–H Functionalization Reactions
2.1 C–H Addition Reactions to Polar Double Bonds
2.2 Cp*Co(CO)I2 and [Cp*CoI2]2 Precursors for the C2-selective C–H Amidation of Indoles
2.3 C–H Functionalization of Carbamoyl-Protected Indoles Using Alkynes
2.4 C–H Allylation Using Allyl Alcohols
2.5 Cyclization Reactions of O-Acyloximes and Alkynes
2.6 Other Miscellaneous Reactions
3 Enantioselective C–H Functionalization Reactions by Hybrid Catalysis
3.1 Cp*RhIII/Chiral Disulfonate Catalysts for the Enantioselective C–H Addition to Enones
3.2 Enantioselective C–H Cleavage Using Chiral Carboxylic Acids
4 Summary and Perspective
Key words
C–H functionalization - C–H activation - cobalt - rhodium - asymmetric catalysis