Copper-catalyzed coupling of aryl iodides and tert-butyl β-keto esters: efficient access to α-aryl ketones and α-arylacetic acid tert-butyl esters

Visible-Light-Mediated Synthesis of α-Aryl Ester Derivatives via an EDA Complex

We report an efficient radical-based and photocatalyst-free method for the C(sp2)-C(sp3) cross-coupling reaction to synthesize α-aryl ester derivatives. The process starts from a β-keto ester and an electron-deficient halogenated aryl halide under alkaline conditions to form an electron donor-acceptor complex and is driven by visible light. From the synthetic point of view, this newly established method represents a simple way to access arylpropionic acids from commercially available and cheap starting materials.

Copper(i)-catalyzed asymmetric intramolecular C-arylation with ureas as the additives: highly enantioselective formation of spirooxindoles

A cooperative catalytic strategy is developed for a copper-catalyzed asymmetric intramolecular C-arylation reaction with ureas as the co-catalysts. By forming hydrogen bonds with 1,3-dicarbonyl structures, ureas can activate the substrates, stabilize the carbanion intermediates and the products, and fix the syn-configurations of 1,3-dicarbonyl structures. They help enhance the reactivity, prevent side reactions and improve the enantioselectivities.

Copper(i)–catalyzed intramolecular asymmetric C-arylation of acyclic β-ester amides: enantioselective formation of chiral oxindoles

A highly efficient intramolecular asymmetric C-arylation of acyclic β-ester amides is demonstrated.

Diversity-oriented synthesis of imidazo[2,1-a]isoquinolines

Herein, we report an efficient and practical strategy for the synthesis of five types of imidazo[2,1-a]isoquinolines via Cp*RhIII-catalyzed [4+2] annulation of 2-arylimidazoles and α-diazoketoesters, whose structural and substituted diversity at 5- or 6-position can be precisely controlled by the α-diazoketoester coupling partners. Compared with previous reports, in this study, we merged two attractive C-C cleavage strategies (retro-Claisen and decarboxylation) into the classical C-H functionalization/condensation process by choosing appropriate ester groups (-COOEt, -COOtBu or -COOiPr) or inexpensive additives (HOAc or KOAc). Moreover, the synthetic efficacies of these methods were demonstrated by the concise synthesis of several bioactive compounds and the late-stage modification of representative drugs.

Selective hydration of asymmetric internal aryl alkynes without directing groups to α-aryl ketones over Cu-based catalyst

The catalyst enlarges the uniqueness of the electron population on the two triple-bond carbon atoms, resulting in highly regioselective hydration.

Metal-free arylation of ethyl acetoacetate with hypervalent diaryliodonium salts: an immediate access to diverse 3-aryl-4(1H)-quinolones

A clean arylation protocol of ethyl acetoacetate was developed using hypervalent diaryliodonium salts under mild and metal-free conditions. The scope of the reaction, using symmetric and unsymmetric iodonium salts with varying sterics and electronics, was examined. Further, this method has been applied for the synthesis of antimalarial compound ELQ-300, which is currently in preclinical development.