Chiral Carboxylic Acid Assisted Enantioselective C–H Activation with Achiral CpxMIII (M = Co, Rh, Ir) Catalysts

Ru(II)-catalyzed enantioselective C-H functionalization involving an enantiodetermining C-H cleavage step remains undeveloped. Here we describe a Ru(II)-catalyzed enantioselective C-H activation/annulation of sulfoximines with α-carbonyl sulfoxonium ylides using a novel class of chiral binaphthyl monocarboxylic acids as chiral ligands, which can be easily and modularly prepared from 1,1'-binaphthyl-2,2'-dicarboxylic acid. A broad range of sulfur-stereogenic sulfoximines were prepared in high yields with excellent enantioselectivities (up to 99% yield and 99% ee) via desymmetrization, kinetic resolution, and parallel kinetic resolution. Furthermore, the resolution products can be easily transformed to chiral sulfoxides and key intermediates for kinase inhibitors.

Efficient Synthesis of Sulfur-Stereogenic Sulfoximines via Ru(II)-Catalyzed Enantioselective C-H Functionalization Enabled by Chiral Carboxylic Acid.

A novel method by a one-step introduction of axial chirality and sterically hindered group has been developed for facile synthesis of axially chiral styrene-type carboxylic acids. With the palladium-catalyzed C–H arylation and olefination of readily available cinnamic acid established, this transformation demonstrated excellent yield, excellent stereocontrol (up to 99% yield and 99% ee), and broad substrate scope under mild conditions. The axially chiral styrene-type carboxylic acids produced have been successfully applied to Cp*CoIII-catalyzed asymmetric C–H activation reactions, indicating their potential as chiral ligands or catalysts in asymmetric synthesis.

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Facile synthesis of axially chiral styrene-type carboxylic acids via palladium-catalyzed asymmetric C-H activation.

Enantioselective C(sp3)–H functionalization reactions using high-valent group 9 metal catalysts with cyclopentadienyl ligands have been achieved by the introduction of appropriate chiral carboxylic...

Development of Pseudo-C2-symmetric Chiral Binaphthyl Monocarboxylic Acids for Enantioselective C(sp3)–H Functionalization Reactions under Rh(III) Catalysis

An unprecedented enantioselective synthesis of spiro-γ-lactams via a sequential C-H olefination/asymmetric [4+1] spirocyclization under a simple Co(II)/chiral spiro phosphoric acid (SPA) binary system is reported. A range of biologically important spiro-γ-lactams are obtained with high levels of enantioselectivity (up to 98% ee). The concise, asymmetric synthesis of an aldose reductase inhibitor was successfully achieved. Notably, contrast to previous reports that relied on the use of cyclopentadienyl or its derivatives (achiral Cp*, Cp tBu , or chiral Cp x ) ligated Co(III) complexes requiring tedious steps to prepare, cheap and commercially available cobalt(II) acetate tetrahydrate was used as an efficient precatalyst.

Synthesis of Chiral Spirolactams via Sequential C−H Olefination/Asymmetric [4+1] Spirocyclization under a Simple Co(II)/Chiral Spiro Phosphoric Acid Binary System

Rhodium(III)/Chiral Carboxylic Acid Catalyzed Enantioselective C(sp3)-H Alkylation of 8-Ethylquinolines with α,β-Unsaturated Carbonyl Compounds.

Ru(II)-catalyzed enantioselective C–H functionalization reactions of sulfoximines with sulfoxonium ylides are described. The combination of [RuCl2(p-cymene)]2 and a pseudo-C
 2-symmetric binaphthyl monocarboxylic acid furnished the S-chiral products in 76:24–92:8 er.

Long-Tao Huang

Papers

Rhodium(III)/Chiral Carboxylic Acid Catalyzed Enantioselective C(sp3)-H Alkylation of 8-Ethylquinolines with α,β-Unsaturated Carbonyl Compounds.

Ru(II)/chiral carboxylic acid-catalyzed enantioselective C–H functionalization of sulfoximines