Enantioselective C−H Bond Functionalization Involving Arene Ruthenium(II) Catalysis

Abstract

The p-Cymene ruthenium(II) complex is one of the most widely used catalysts in CÀ H activation. However, enantioselective CÀ H activation promoted by arene ruthenium(II) complexes has not been realized until recently. The revealed strategies include intramolecular nitrene CÀ H insertion, the use of chiral transient directing groups, chiral carboxylic acid, relay catalysis, and chiral arene ligands. In this minireview, these advances are summarized and discussed in the hope of spurring further developments.

Copper/BINOL-Catalyzed Enantioselective C–H Functionalization toward Planar Chiral Ferrocenes Under Mild Conditions

“…Over the past years, transition metal-catalyzed enantioselective C–H activation has emerged as a powerful and efficient tool for the construction of molecular chirality . Significant progresses have been achieved on asymmetric C–H functionalization catalyzed by noble transition metals .…”

Rhodium-Catalyzed Asymmetric C–H Functionalization Reactions

“…Among these, transition-metal-catalyzed asymmetric C–H functionalization reactions have provided powerful access to the synthesis of diverse enantioenriched compounds in a highly enantioselective manner. − Generally speaking, there are three different pathways for achieving asymmetric C–H functionalization reactions, desymmetrization, kinetic resolution, and the addition to unsaturated compounds (Scheme ). Asymmetric C–H functionalization reactions can be catalyzed by various transition-metal complexes including palladium (Pd), − rhodium (Rh), − iridium (Ir), − ruthenium (Ru), − and other 3d transition metals. − Among these, Pd and Rh catalysts have received the most attention due to their applications in diverse enantioselective reactions with broad substrate scope. In this regard, Pd-catalyzed asymmetric C–H functionalization reactions have been extensively investigated and well-reviewed.…”

Planar-chiral arene ruthenium complexes: synthesis, separation of enantiomers, and application for catalytic C–H activation

“…Asymmetric transformations have been achieved using a number of rhodium complexes with chiral cyclopentadienyl ligands. 4–7 On the contrary, ruthenium complexes with chiral arene ligands are scarce and their first applications as catalysts for C–H activation reactions have been reported only two years ago, 8 although complementary approaches using chiral carboxylic acids 9–11 and chiral directing groups 12–15 have been developed. In particular, our group has synthesized a ruthenium complex with an arene ligand derived from chiral natural camphor, but unfortunately it turned out to be too hindered and susceptible to replacement of the arene in C–H activation reactions.…”