The selective replacement of C–H bonds in complex molecules, especially natural products like terpenoids, is a highly efficient way to introduce new functionality and/or couple fragments. Here, we report the development of a new metal-free allylic amination of alkenes that allows the introduction of a wide range of nitrogen functionality at the allylic position of alkenes with unique regioselectivity and no allylic transposition. This reaction employs catalytic amounts of selenium in the form of phosphine selenides or selenoureas. Simple sulfonamides and sulfamates can be used directly in the reaction without the need to prepare isolated nitrenoid precursors. We demonstrate the utility of this transformation by aminating a large set of terpenoids in high yield and regioselectivity.

A palladium-catalyzed cross-coupling of 2-alkylaziridines with alkenylboronic acids to give homoallylamines is presented. The reaction is highly regioselective and stereospecific and provides convenient access to enantioenriched amines with 1,1-disubstituted, 1,2-disubstituted, and trisubstituted alkenes. The modular synthesis of a 2,5-disubstituted pyrrolidine natural product was completed in three steps and 67% overall yield.

Post-polymerization modification (PPM) via direct CÀ H functionalization is a powerful synthetic strategy to convert polymer feed-stocks into valueadded products. We found that a metal-free, Secatalyzed allylic CÀ H amination provided an efficient method for PPM of polynorbornenes (PNBs) produced via ring-opening metathesis polymerization. Inherent to the mechanism of the allylic amination, PPM on PNBs preserved the alkene functional groups along the polymer backbone, while also avoiding transposition of the double bonds. Amination using a series of aryl sulfonamides led to good control over the degree of functionalization, access to a range of functionalities, and tunable thermal properties from the resulting polymers.

Background Pediatric gliomas comprise a diverse set of brain tumor entities that have substantial long-term ramifications for patient survival and quality of life. However, the study of these tumors is currently limited due to a lack of authentic models. Additionally, many aspects of pediatric brain tumor biology, such as tumor cell invasiveness, have been difficult to study with currently available tools. To address these issues, we developed a synthetic extracellular matrix (sECM)-based culture system to grow and study primary pediatric brain tumor cells. Methods We developed a brain-like sECM material as a supportive scaffold for the culture of primary, patient-derived pediatric glioma cells and established patient-derived cell lines. Primary juvenile brainstem-derived murine astrocytes were used as a feeder layer to support the growth of primary human tumor cells. Results We found that our culture system facilitated the proliferation of various primary pediatric brain tumors, including low-grade gliomas, and enabled ex vivo testing of investigational therapeutics. Additionally, we found that tuning this sECM material allowed us to assess high-grade pediatric glioma cell invasion and evaluate therapeutic interventions targeting invasive behavior. Conclusion Our sECM culture platform provides a multipurpose tool for pediatric brain tumor researchers that enables both a wide breadth of biological assays and the cultivation of diverse tumor types.

Since its introduction by Cravatt and colleagues in 1999, activity‐based protein profiling (ABPP) has become widely utilized throughout academia, government, and industry laboratories to study enzymes spanning numerous gene families in a multitude of biological systems. As a variation of ABPP, competitive ABPP provides a powerful approach to characterize the binding behavior of small molecule probes and clinical drugs throughout the functional proteome. The power and flexibility of competitive ABPP are exemplified by a wide range of creative adaptions which increase assay throughput, enable diverse detection schemes, and support the implementation of this approach within a hybrid target‐based screening platform. We review major developments in competitive ABPP through a compare‐contrast format to provide a useful introduction to this enabling technology for scientists in chemical biology and drug discovery.