Although Cp*Rh(III) complexes are prominent and versatile catalysts for C-H bond functionalization reactions, catalytic stereocontrol is difficult due to the lack of vacant coordination sites. Here we report a hybrid strategy for inducing chirality without using previously reported chiral Cp x ligands. A preformed hybrid catalyst, [Cp*RhL N ][6,6'-Br-(S)-BINSate], catalyzed C-H activation and subsequent conjugate addition of 2-phenylpyridine derivatives to enones in good yield and enantioselectivity (up to 95:5 er). In addition to 2-phenylpyridines, conjugate addition of 6-arylpurines proceeded in up to 91:9 er using [Cp*RhL N ][(R)-SPISate]. The results demonstrated that a chiral organic anion can efficiently control the enantioselectivity of Cp*Rh(III)-catalyzed C-H bond functionalization without a chiral Cp x ligand. Transition metal catalysts cleave inert carbon-hydrogen (C-H) bonds in organic molecules to form reactive organometallic intermediates, enabling catalytic transformation of C-H bonds to desired carbon-carbon and carbon-heteroatom bonds. This catalytic C-H bond functionalization strategy can facilitate the development of atom-1 and step-economical 2 syntheses of functional molecules, and thus has been intensively investigated over the several decades. 3-16 Among various types of transition metal catalysts studied for catalytic C-H bond functionalization, Rh(III) complexes bearing a pentamethylcyclopentadienyl (Cp*) or related cyclopentadienyl-type (Cp,

Transition‐metal‐catalyzed C−H functionalization reactions with Cp*MIII catalysts (M=Co, Rh, Ir) have found a wide variety of applications in organic synthesis. Albeit the intrinsic difficulties in achieving catalytic stereocontrol using these catalysts due to their lack of additional coordination sites for external chiral ligands and the conformational flexibility of the Cp ligand, catalytic enantioselective C−H functionalization reactions using the Group 9 metal triad with Cp‐type ligands have been intensively studied since 2012. In this minireview, the progress in these reactions according to the type of the chiral catalyst used are summarized and discussed. The development of chiral Cpx ligands the metal complexes thereof, artificial metalloenzymes, chiral carboxylate‐assisted enantioselective C−H activations, enantioselective alkylations assisted by chiral carboxylic acids or chiral sulfonates, and chiral transient directing groups are discussed.

1,1'-Spirobiindane-7,7'-disulfonic acid (SPISA) and 1,1'-spirobiindane-7,7'-disulfonimide were synthesized from 1,1'-spirobiindane-7,7'-diol (SPINOL) in 4 steps using a Pd-catalyzed Newman-Kwart rearrangement as a key step. These new catalysts possessing a rigid spirocyclic backbone were evaluated in a catalytic asymmetric aminalization reaction, and SPISA/iPr NEt exhibited high enantioselectivity, demonstrating the utility of SPISA as a chiral Brønsted acid catalyst.

C−H activation with cyclopentadienyl complexes: Transition‐metal‐catalyzed C−H functionalization reactions with Cp*MIII catalysts (M=Co, Rh, Ir) have found a wide variety of applications in organic synthesis. Albeit the intrinsic difficulties in achieving catalytic stereocontrol using these catalysts due to their lack of additional coordination sites for external chiral ligands and the conformational flexibility of the Cp ligand, catalytic enantioselective C−H functionalization reactions using the Group 9 metal triad with Cp‐type ligands have been intensively studied since 2012. In this Minireview on page 7346 ff., T. Yoshino, S. Satake and S. Matsunaga summarize and discuss the progress in these reactions according to the type of the chiral catalyst used. The development of chiral Cpx ligands and their metal complexes, artificial metalloenzymes, chiral carboxylate‐assisted enantioselective C−H activations, enantioselective alkylations assisted by chiral carboxylic acids or chiral sulfonates, and chiral transient directing groups are discussed.

The enantioselective intramolecular oxyamination of unsaturated alkoxyamines using a hybrid catalytic system consisting of Cp*RhIII/chiral disulfonate/CuOAc is described. Tetrahydrofuran derivatives with a tetrasubstituted chiral center were obtained under the optimized conditions in 91:9–97:3 er. The use of a sterically hindered chiral disulfonate and a Cu additive was essential for the high enantioselectivity.