Potent Inhibition and Rapid Photoactivation of Endogenous Bruton's Tyrosine Kinase Activity in Native Cells via Opto-Covalent Modulators.

Naturally, kinases exert their activities in a highly regulated fashion. A number of ingenious approaches have been developed to artificially control kinase activity by external stimuli, such as the incorporation of unnatural amino acids or the fusion of additional protein domains; however, methods that directly modulate endogenous kinases in native cells are lacking. Herein, we present a facile and potent method that takes advantage of recent developments in targeted covalent inhibitors and rapid light-mediated uncaging chemistry.

Development of visible-light-activatable photocaged PROTACs.

Photocaged proteolysis-targeting chimeras (PROTACs), which employ light as a stimulus to control protein degradation, have recently garnered considerable attention as both powerful chemical tools and a promising therapeutic strategy. However, the poor penetration depth of traditionally used ultraviolet light and the deficiency of alternative caging positions have restricted their applications in biological systems. By installing a diverse array of photocaged groups, with excitation wavelengths ranging from 365 nm to 405 nm, onto different positions of cereblon (CRBN) and Von Hippel-Lindau (VHL)-recruiting Brd4 degraders, we conducted the first comprehensive study on visible-light-activatable photocaged PROTACs to the best of our knowledge.

Visible-Light-Promoted Manganese-Catalyzed Atom Transfer Radical Cyclization of Unactivated Alkyl Iodides.

An expedient visible-light-promoted atom transfer radical cyclization (ATRC) reaction of unactivated alkyl iodides facilitated by earth-abundant and inexpensive manganese catalysis is described. The practical protocol shows a broad substrate scope and good functional-group tolerance, allowing for the preparation of synthetically valuable alkenyl iodides and diquinanes under simple and mild reaction conditions. Notably, the method provides a net redox-neutral strategy for ATRC reactions that avoids classic hydrogen atom transfer mechanism.

Visible-Light-Mediated Aerobic Oxidation of Organoboron Compounds Using in Situ Generated Hydrogen Peroxide.

A simple and general visible-light-mediated oxidation of organoboron compounds has been developed with rose bengal as the photocatalyst, substoichiometric EtN as the electron donor, as well as air as the oxidant. This mild and metal-free protocol shows a broad substrate scope and provides a wide range of aliphatic alcohols and phenols in moderate to excellent yields. Notably, the robustness of this method is demonstrated on the stereospecific aerobic oxidation of organoboron compounds.

Visible-Light-Initiated, Photocatalyst-Free Decarboxylative Coupling of Carboxylic Acids with N-Heterocycles.

A general and efficient protocol for direct C-H alkylation and acylation of N-heterocycles, using readily accessible carboxylic acids as radical precursors under visible-light irradiation without a photocatalyst and an additional acid additive, has been developed. This protocol provides expedient access to substituted N-heterocycles under mild and metal-free conditions. Mechanistic experiments indicate that this reaction proceeds through a visible-light-initiated radical chain propagation mechanism.

Mild and efficient synthesis of indoles and isoquinolones via a nickel-catalyzed Larock-type heteroannulation reaction.

A simple and efficient approach for the preparation of substituted indoles and isoquinolones via a nickel-catalyzed Larock-type heteroannulation reaction is reported. This transformation employed air-stable and inexpensive Ni(dppp)Cl as a precatalyst and EtN as a mild base. Moreover, the reaction occurs efficiently under mild conditions, and a wide range of substituted indoles and isoquinolones bearing various functional groups are obtained in moderate to excellent yields.

Eosin Y-catalyzed, visible-light-promoted carbophosphinylation of allylic alcohols via a radical neophyl rearrangement.

A visible-light-promoted phosphinylation of allylic alcohols with concomitant 1,2-aryl migration is described. This transformation proceeds smoothly under metal-free and mild conditions by using an inexpensive organic dye, eosin Y, as the photocatalyst, affording various β-aryl-γ-ketophosphine oxides in moderate to good yields. Mechanistic studies suggested that the 1,2-aryl migration proceeded through a radical (neophyl) rearrangement.

Recent Advances in the Synthesis of β-Functionalized Ketones by Radical-Mediated 1,2-Rearrangement of Allylic Alcohols.

β-Functionalized ketones are a highly important and valuable class of compounds that have gained increasing attention from organic chemists due to their intensive uses as versatile synthetic intermediates and building blocks in complex molecule assembly and natural product synthesis. Accordingly, there is continuing interest in the development of new approaches for the synthesis of β-functionalized ketones. In recent years, radical-mediated 1,2-rearrangement reactions of allylic alcohols, which proceed through cationic (semipinacol) rearrangements or radical (neophyl) rearrangements, have presented an attractive and powerful strategy to access various diversely β-functionalized ketones.

α-Quaternary Mannich Bases through Copper-Catalyzed Amination-Induced 1,2-Rearrangement of Allylic Alcohols.

A novel copper-catalyzed amination-induced 1,2-rearrangement reaction of allylic alcohols has been developed under simple and mild conditions. The commercially available N-fluorobenzenesulfonimide (NFSI) is employed as an amination reagent. In this transformation, not only alkyl, but also aryl substituents can efficiently undergo 1,2-carbon atom migration, thereby providing an efficient and powerful route to prepare a wide range of α-quaternary Mannich bases.