Asymmetric Synthesis of a Glucagon Receptor Antagonist via Friedel–Crafts Alkylation of Indole with Chiral α-Phenyl Benzyl Cation

Cobalt-Catalyzed Enantioconvergent Negishi Cross-Coupling of α-Bromoketones

Cobalt-catalyzed enantioconvergent cross-coupling of α-bromoketones with aryl zinc reagents is achieved to access chiral ketones bearing α-tertiary stereogenic centers with high enantioselectivities. The more challenging and sterically hindered α-bromoketones bearing a 2-fluorophenyl group or β-secondary and tertiary alkyl chains could also be well-tolerated. Adjusting the electronic effect of chiral unsymmetric N,N,N-tridentate ligands is critical for improving the reactivity and selectivity of this transformation, which is beneficial for further studies of asymmetric 3d metal catalysis via ligand modification. The control experiments and kinetic studies illustrated that the reaction involved radical intermediates and the reductive elimination was a rate-determining step.

Enantioselective Transformations in the Synthesis of Therapeutic Agents

The proportion of approved chiral drugs and drug candidates under medical studies has surged dramatically over the past two decades. As a consequence, the efficient synthesis of enantiopure pharmaceuticals or their synthetic intermediates poses a profound challenge to medicinal and process chemists. The significant advancement in asymmetric catalysis has provided an effective and reliable solution to this challenge. The successful application of transition metal catalysis, organocatalysis, and biocatalysis to the medicinal and pharmaceutical industries has promoted drug discovery by efficient and precise preparation of enantio-enriched therapeutic agents, and facilitated the industrial production of active pharmaceutical ingredient in an economic and environmentally friendly fashion. The present review summarizes the most recent applications (2008-2022) of asymmetric catalysis in the pharmaceutical industry ranging from process scales to pilot and industrial levels. It also showcases the latest achievements and trends in the asymmetric synthesis of therapeutic agents with state of the art technologies of asymmetric catalysis.

Biomimetic Total Synthesis and the Biological Evaluation of Natural Product (-)-Fargesone A as a Novel FXR Agonist

Farnesoid X receptor (FXR), a member of the nuclear receptor superfamily, plays an important role in maintaining or reversing metabolic homeostasis during the development of liver diseases. However, developing FXR modulators to intervene in FXR-related diseases is still an unmet clinical need. Therefore, it is significant to develop novel small-molecule agonists for drug discovery targeting FXR. Through a high-throughput chemical screen and follow-up biological validations, we first identified the natural product Fargesone A (FA) as a potent and selective FXR agonist. The limited, variable supply of FA from natural product isolation, however, has impeded its biological exploration and potential drug development. Accordingly, we have developed a biomimetic and scalable total synthesis of FA in nine steps that provides a solution to the supply of FA. Enabled by chemical synthesis, the in vivo efficacy of FA has been further investigated. The results showed that FA alleviates hepatocyte lipid accumulation and cell death in an FXR-dependent manner. Moreover, treatment of bile duct ligation (BDL)-induced liver disorder with FA ameliorates pathological features in mice. Therefore, our work lays the foundation to develop new small-molecule FXR agonists as a potential therapy for liver diseases.

Hierarchical Catalysts Prepared by Interzeolite Transformation

Interzeolite transformation has been used to produce a novel family of hierarchical catalysts featuring excellent textural properties, strong acidity, and superior catalytic performance for the Friedel-Crafts alkylation of indole with benzhydrol, the Claisen-Schmidt condensation of benzaldehyde and hydroxyacetophenone, and the cracking of polystyrene. Intermediate solids of the FAU interzeolite transformation into BEA display both increased accessibility─due to the development of mesoporosity─and strong acidity─caused by the presence of ultrasmall crystals or zeolitic fragments in their structure. The use of surfactants allows for the development of the hierarchical catalysts with very narrow pore size distribution. The properties of interzeolite transformation intermediates (ITIs) can be fine-tuned simply by stopping the interconversion at different times.

Research progress of indole compounds with potential antidiabetic activity

New types of antidiabetic agents are continually needed with diabetes becoming the epidemic in the world. Indole alkaloids play an important role in natural products owing to their variable structures and versatile biological activities like anticonvulsant, anti-inflammatory, antidiabetic, antimicrobial, and anticancer activities, which are a promising source of novel antidiabetic drugs discovery. The synthesized indole derivatives possess similar properties to natural indole alkaloids. In the last two decades, more and more indole derivatives have been designed and synthesized for searching their bioactivities. This present review describes comprehensive structures of indole compounds with the potential antidiabetic activity including natural indole alkaloids and the synthetic indole derivatives based on the structure classification, summarizes their approaches isolated from natural sources or by synthetic methods, and discusses the antidiabetic effects and the mechanisms of action. Furthermore, this review also provides briefly synthetic procedures of some important indole derivatives.

Access to Optically Pure Benzosultams by Superelectrophilic Activation

Through superacid activation, N-(arenesulfonyl)-aminoalcohols derived from readily available ephedrines or amino acids undergo an intramolecular Friedel-Crafts reaction to afford enantiopure benzosultams bearing two adjacent stereocenters in high yields with fully controlled diastereoselectivity. Low-temperature NMR spectroscopy demonstrated the crucial role played by the conformationally restricted chiral dicationic intermediates.

Surfactant-templated zeolites for the production of active pharmaceutical intermediates

A hierarchical USY zeolite has been produced using the surfactant-templating method and used as a catalyst for the production of two important active pharmaceutical ingredients. The presence of intracrystalline mesoporosity in the zeolite results in a significant increase in both the activity (up to 30 fold increase in TOF) and reusability for Friedel-Crafts alkylation and aldol condensation steps.

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

Stereoconvergent catalysis is an important subset of asymmetric synthesis that encompasses stereoablative transformations, dynamic kinetic resolutions, and dynamic kinetic asymmetric transformations. Initially, only enzymes were known to catalyze dynamic kinetic processes, but recently various synthetic catalysts have been developed. This Review summarizes major advances in nonenzymatic, transition-metal-promoted dynamic asymmetric transformations reported between 2005 and 2015.

C7-derivatization of C3-alkylindoles including tryptophans and tryptamines

A versatile strategy for C7-selective boronation of tryptophans, tryptamines, and 3-alkylindoles by way of a single-pot C2/C7-diboronation-C2-protodeboronation sequence is described. The combination of a mild iridium-catalyzed C2/C7-diboronation followed by an in situ palladium-catalyzed C2-protodeboronation allows efficient entry to valuable C7-boroindoles that enable further C7-derivatization. The versatility of the chemistry is highlighted by the gram-scale synthesis of C7-boronated N-Boc-L-tryptophan methyl ester and the rapid synthesis of C7-halo, C7-hydroxy, and C7-aryl tryptophan derivatives.