Feng Hu

Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) are a popular chemogenetic technology for manipulation of neuronal activity in uninstrumented awake animals with potential for human applications as well. The prototypical DREADD agonist clozapine N-oxide (CNO) lacks brain entry and converts to clozapine, making it difficult to apply in basic and translational applications. Here we report the development of two novel DREADD agonists, JHU37152 and JHU37160, and the first dedicated ¹⁸F positron emission tomography (PET) DREADD radiotracer, [¹⁸F]JHU37107. We show that JHU37152 and JHU37160 exhibit high in vivo DREADD potency. [¹⁸F]JHU37107 combined with PET allows for DREADD detection in locally-targeted neurons, and at their long-range projections, enabling noninvasive and longitudinal neuronal projection mapping.

A rare example of highly selective σ N–C bond difunctionalization in bridged twisted lactams through N–C cleavage has been achieved. In combination with the intramolecular Heck cyclization, this method affords a two-step bond reorganization event (“sew-and-cut”) to access functionalized isoquinoline ring systems directly with high atom economy. C–H bond functionalizations directed by a weakly coordinating bridged amide bond increase scaffold diversity. Preliminary mechanistic studies on the effect of amide distortion and the role of electrophile in this unusual σ N–C amide difunctionalization are described.

A versatile method for the Ru(0)-catalyzed hydroarylation of alkynes using weakly-coordinating ketones enabled by the in situ generation of a Ru(0) catalyst from an air-stable, inexpensive and user-friendly Ru(II) precatalyst is reported for the first time. The method provides straightforward access to a wide range of functionalized ketone building blocks that would be difficult to access by conventional methods. Most crucially, this report demonstrates for the first time that the in situ generated Ru(0) catalysts advance the classic Ru(0)-catalyzed C–H functionalization platform to substrates that would otherwise be unreactive. Product manipulation and mechanistic studies are reported.

Herein, we describe the first structural characterization of N‐alkylated twisted amides prepared directly by N‐alkylation of the corresponding non‐planar lactams. This study provides the first experimental evidence that N‐alkylation results in a dramatic increase of non‐planarity around the amide N−C(O) bond. Moreover, we report a rare example of a molecular wire supported by the same amide C=O‐Ag bonds. Reactivity studies demonstrate rapid nucleophilic addition to the N−C(O) moiety of N‐alkylated amides, indicating the lack of n_N to π^*_C=O conjugation. Most crucially, we demonstrate that N‐alkylation activates the otherwise unreactive amide bond towards σ N−C cleavage by switchable coordination.

Transition-metal-catalyzed alkylation reactions of arenes have become a central transformation in organic synthesis. Herein, we report the first general strategy for alkylation of arenes with styrenes and alcohols catalyzed by carbon-based materials, exploiting the unique property of graphenes to produce valuable diarylalkane products in high yields and excellent regioselectivity. The protocol is characterized by a wide substrate scope and excellent functional group tolerance. Notably, this process constitutes the first general application of graphenes to promote direct C–C bond formation utilizing polar functional groups anchored on the GO surface, thus opening the door for an array of functional group alkylations using benign and readily available graphene materials. Mechanistic studies suggest that the reaction proceeds via a tandem catalysis mechanism in which both of the coupling partners are activated by interaction with the GO surface.

An efficient and convenient method for the synthesis of diaryl sulfones was developed through the Cu‐catalyzed cross‐couplings of arylsulfonyl chlorides and arylboronic acids at room temperature in open air. This method is characterized by the use of inexpensive and readily available catalyst and substrates, mild reaction conditions, wide functionality tolerance, short reaction times for most substrates, and moderate to good yields.

The cascade involves 1,4‐addition, cyclization and hydrolysis to provide various multisubstituted 3‐acylfurans in a convenient manner.

An efficient gold‐catalyzed domino reaction producing functionalized furanones via a proposed sequence of cyclization, C‐C cleavage, nucleophilic addition, oxidation, and nucleophilic addition, is reported.

The reaction is proposed to proceed via an initial Heck reaction followed by a sp²‐sp³‐coupling, reductive elimination and a final retro‐Diels—Alder step.