Facile Synthesis of Isoindolinones via Rh(III)-Catalyzed One-Pot Reaction of Benzamides, Ketones, and Hydrazines

Redox-Neutral Rhodium-Catalyzed [4+1] Annulation through Formal Dehydrogenative Vinylidene Insertion

A synthetic protocol for the expedient construction of 5-methylene-1H-pyrrol-2(5H)-one derivatives through rhodium-catalyzed [4+1] annulation with gem-difluoroacrylate as the C₁ component was reported. By taking advantage of the twofold C-F bond cleavage occurring during the annulation, this reaction not only allows the synthesis of these heterocyclic compounds under overall oxidant-free conditions but also renders the transformation stereospecific. The very mild reaction conditions employed ensure compatibility with a wide variety of synthetically useful functional groups.

A Simple and Versatile Amide Directing Group for C-H Functionalizations

Achieving selective C-H activation at a single and strategic site in the presence of multiple C-H bonds can provide a powerful and generally useful retrosynthetic disconnection. In this context, a directing group serves as a compass to guide the transition metal to C-H bonds by using distance and geometry as powerful recognition parameters to distinguish between proximal and distal C-H bonds. However, the installation and removal of directing groups is a practical drawback. To improve the utility of this approach, one can seek solutions in three directions: 1) Simplifying the directing group, 2) using common functional groups or protecting groups as directing groups, and 3) attaching the directing group to substrates via a transient covalent bond to render the directing group catalytic. This Review describes the rational development of an extremely simple and yet broadly applicable directing group for Pd(II) , Rh(III) , and Ru(II) catalysts, namely the N-methoxy amide (CONHOMe) moiety. Through collective efforts in the community, a wide range of C-H activation transformations using this type of simple directing group have been developed.

Exploiting the Bis-Nucleophilicity of α-Aminoboronates: Copper-Catalyzed, Intramolecular Aminoalkylations of Bromobenzoyl Chlorides

α-Aminoboronate salts are interesting examples of heteroatomic species containing adjacent nucleophilic centers. We have developed an acylation/arylation reaction using 2-bromobenzoyl chlorides as bis-electrophiles that harnesses the nucleophilicity of both positions, leading to isoindolinones. The reactions proceed under mild conditions via an intramolecular, Cu-catalyzed sp(3)-sp(2) coupling, giving products in up to 95% yield. These conditions enable arylation of α,α-disubstituted aminoboronates, which are difficult to accomplish using methods based on less abundant and more expensive transition metals.

Iridium(iii)- and rhodium(iii)-catalyzed coupling of anilines with α-diazoesters via chelation-assisted C–H activation

Ir(iii) catalysts can catalyze the efficient synthesis of indoles via C–H activation of anilines in the coupling with α-diazo β-ketoesters.

Rh(iii)-catalyzed C–H activation/cyclization of oximes with alkenes for regioselective synthesis of isoquinolines

A Rh(iii)-catalyzed C–H activation/cyclization of oximes and alkenes for facile and regioselective access to isoquinolines has been developed.

Rhodium-catalyzed C–H activation of 3-(indolin-1-yl)-3-oxopropanenitriles with diazo compounds and tandem cyclization leading to hydrogenated azepino[3,2,1-hi]indoles

Rh(iii)-Catalyzed C–H activation of 3-(indolin-1-yl)-3-oxopropanenitriles with diazo compounds and tandem cyclization leading to seven-membered ring scaffolds has been developed.

Fe-Catalyzed Reductive Coupling of Unactivated Alkenes with β-Nitroalkenes

An Fe-catalyzed reductive coupling of unactivated alkenes with β-nitroalkenes has been developed. The reaction proceeds through a radical pathway, with β-nitroalkenes serving as the vinylating reagents and the nitro group being cleaved in the process. Therefore, this method provides a viable synthetic approach to valuable secondary- and tertiary-alkylated styrene derivatives. Furthermore, control experiments were conducted and a plausible mechanism is proposed.