Synthesis of Indole-Fused Polycyclics via Rhodium-Catalyzed Undirected C-H Activation/Alkene Insertion

Rhodium-Catalyzed Enantioselective Addition of Heteroarenium Salts Enabled by Nucleophilic Cyclization of 2-Alkynylanilines

Transition-metal-catalyzed cyclative coupling of 2-alkynylanilines provides a feasible routine for accessing functionalized indoles. Herein, a rhodium-catalyzed highly enantioselective addition of heteroarenium salts is presented, which is enabled by the nucleophilic cyclization of 2-alkynylanilines. It offers feasible protocols to access enantioenriched functionalized indoles tethered to 1,2-dihydropyridine and 1,2-dihydroquinoline motifs with excellent enantioselectivities.

Palladium-Catalyzed Synthesis of Functionalized Indoles by Acylation/Allylation of 2-Alkynylanilines with Three-Membered Rings

Palladium-catalyzed synthesis of 3-acyl and -allyl indoles has been realized by merging nucleophilic cyclization of ortho-alkynylanilines with ring opening of three-membered rings such as cyclopropenones and gem-difluorinated cyclopropanes. These functionalized indoles were obtained in moderate to high yields with high stereoselectivity in both cases. This protocol provides an alternative method toward functionalized indoles under mild and redox-neutral conditions.

Sequential Pd0 - and PdII -Catalyzed Cyclizations: Enantioselective Heck and Nucleopalladation Reactions

An enantioselective consecutive cyclization/coupling process, catalyzed by palladium is reported. Stereoinduction arises from an enantioselective carbopalladation, generating an intermediate which promotes a nucleopalladation step. The dual cyclization sequence was compatible with a variety of alkyne-tethered oxygen- and nitrogen-centered nucleophiles, and a variety of alkenyl-tethered aryl iodides, to forge numerous bisheterocycles in good yields and high regio- and enantioselectivities.

Building a Chemical Toolbox for Human Pregnane X Receptor Research: Discovery of Agonists, Inverse Agonists, and Antagonists Among Analogs Based on the Unique Chemical Scaffold of SPA70

Pregnane X receptor (PXR) plays roles in detoxification and other physiological processes. PXR activation may enhance drug metabolism (leading to adverse drug reactions) or inhibit inflammation. Therefore, PXR agonists, antagonists, and inverse agonists may serve as research tools and drug candidates. However, a specific PXR modulator with an associated structure-activity relationship is lacking. Based on the scaffold of specific human PXR (hPXR) antagonist SPA70 (10), we developed 81 SPA70 analogs and evaluated their receptor-binding and cellular activities. Interestingly, analogs with subtle structural differences displayed divergent cellular activities, including agonistic, dual inverse agonistic and antagonistic, antagonistic, and partial agonistic/partial antagonistic activities (as in compounds 111, 10, 97, and 42, respectively). We generated a pharmacophore model that represents 81 SPA70 analogs, and docking models that correlate strong interactions between the compounds and residues in the AF-2 helix with agonistic activity. These compounds are novel chemical tools for studying hPXR.

An approach to unsymmetrical 3,3′-diindolylmethanes through Pd-catalyzed cascade Heck cyclization of allenamides and o-ethynylanilines

A highly efficient synthesis of unsymmetrical 3,3′-diindolylmethanes has been developed by palladium-catalyzed cascade Heck/cyclization reaction.

Rhodium(III)-Catalyzed Cyclopropane C-H/C-C Activation Sequence Provides Diastereoselective Access to α-Alkoxylated γ-Lactams

A Cp*Rh(III)-catalyzed C-H/C-C bond activation sequence of cyclopropyl hydroxamates has been developed. The three-component process allows trapping of the intermediate rhodacycle with diazomalonates and an alcohol nucleophile to provide access to synthetically valuable α-alkoxylated γ-lactams with trans diastereoselectivity.

Recent advances in transition metal migration involving reactions

In this review, various types of metal-migration involved methodologies, including palladium, rhodium, iron, cobalt, iridium, chromium, nickel, platinum, are summarized and demonstrated elaborately for giving a better access to this field.