Zhong Lian

Alkene hydrogenation reactions are essential processes widely utilized across diverse scientific fields for the production of pharmaceuticals, natural products, and various functional materials. Current strategies (e.g., metal hydrogen atom transfer [mHAT], photo/electrochemistry) consistently necessitate compromises, invariably involving transition metals, pressurized H ₂ , or solvent‐intensive conditions. Herein, we report a mechanochemical hydrogenation reaction of both activated and unactivated alkenes via piezoelectric catalysis under conditions that are free from transition‐metals, H ₂ gas, and solvents. This approach exhibits good compatibility with various functional groups and demonstrates a broad substrate scope. In addition, the hydrogenation of bioactive molecule derivatives for modification purposes highlights its potential applications in the pharmaceutical industry. Based on mechanistic investigations, we propose a potential mechanism for the alkene hydrogenation via piezoelectric catalysis.

A mechanochemical, base-catalyzed strategy achieves rapid, metal-free isomerization and deuteration of allylbenzenes, enabling precise CD ₃ incorporation under ambient conditions within 15 minutes.

Radical‐mediated selenylation has emerged as a powerful strategy for constructing carbon‐selenium bonds. While effective for generating aryl selenyl radicals, current approaches for producing alkyl selenyl radicals remain underdeveloped. In this study, we present a mechanochemical approach that enables the modular generation of alkyl selenyl radicals from elemental selenium and alkyl halides, thereby advancing the hydroselenation of alkenes. The modular generation of alkyl selenyl radicals utilizes abundant and commercially available alkyl (pseudo)halides as radical precursors, activated through mechanical force to overcome selenium's inherent inertness. The reaction proceeds under ambient conditions with minimal solvent usage, achieving a broad substrate scope encompassing alkyl iodides, bromides, chlorides, and sulfonates. Notably, mechanistic experiments and density functional theory (DFT) calculations indicate that both PhSiH ₃ or/and H ₂ O can function as hydrogen atom donors through a radical pathway. This finding appears to be significant in the case of water, where the oxophilicity of silicon likely provides the driving force, pointing to a plausible silicon‐mediated activation of water. We therefore propose a mechanochemical silicon‐mediated radical process where coordination‐induced bond weakening could enable intermolecular hydrogen atom transfer (HAT) from H ₂ O to carbon radicals.

The palladium‐catalyzed Suzuki–Miyaura cross‐coupling reaction is considered as a crucial technique in the field of organic chemistry. Traditionally, the reaction between aryl diazonium salts and arylboronic acids in solution predominantly facilitates carbon–carbon (C─C) bond formation. However, our research reveals that mechanochemical techniques can shift the chemical selectivity in Suzuki–Miyaura cross‐coupling, resulting in the generation of non‐symmetric azobenzene compounds under neat milling conditions. Azobenzenes have progressed from being merely textile dyes to multifunctional molecular systems critical for advanced technologies; however, the synthetic challenges associated with non‐symmetric azo derivatives remain significant. Here, we present an innovative methodology that eliminates the use of conventional solvents while demonstrating exceptional substrate compatibility and short reaction time under ambient conditions. Detailed mechanistic investigations suggest that mechanochemical conditions alter the reaction pathway by selectively promoting carbon–nitrogen (C─N) coupling.

The palladium‐catalyzed Suzuki–Miyaura cross‐coupling reaction is considered as a crucial technique in the field of organic chemistry. Traditionally, the reaction between aryl diazonium salts and arylboronic acids in solution predominantly facilitates carbon–carbon (C─C) bond formation. However, our research reveals that mechanochemical techniques can shift the chemical selectivity in Suzuki–Miyaura cross‐coupling, resulting in the generation of non‐symmetric azobenzene compounds under neat milling conditions. Azobenzenes have progressed from being merely textile dyes to multifunctional molecular systems critical for advanced technologies; however, the synthetic challenges associated with non‐symmetric azo derivatives remain significant. Here, we present an innovative methodology that eliminates the use of conventional solvents while demonstrating exceptional substrate compatibility and short reaction time under ambient conditions. Detailed mechanistic investigations suggest that mechanochemical conditions alter the reaction pathway by selectively promoting carbon–nitrogen (C─N) coupling.

Deuterium labeling is extensively utilized across various scientific disciplines. The dehalogenative deuteration of organic halides offers a promising approach for achieving deuterium labeling. However, existing methods for dehalogenative deuteration primarily focus on sp ² ‐hybridized aryl halides, while sp ³ ‐hybridized alkyl halides, especially bromides and chlorides, exhibit low reactivity and pose significant challenges for reduction. This limitation hampers the development of deuteration methodologies. In this study, a robust and versatile mechanochemical strategy is introduced for deuterating both activated and unactivated alkyl halides (X = Cl, Br, I), employing D ₂ O as an economical deuterium source and electron donor, catalyzed by a piezoelectric material. Importantly, unlike previously mechanochemical piezoelectric catalysis reactions that are typically initiated by a single‐electron reduction process, this transformation is triggered by a single‐electron oxidation pathway. Employing this innovative technique, a variety of organic halides are successfully converted, including primary, secondary, and tertiary alkyl halides, into deuterated products with good yields and high deuterium incorporation, using only a chemically equivalent amount of D ₂ O. The practical application of this green and efficient methodology is further demonstrated by late‐stage deuteration on drug molecule analogs, underscoring its potential utility in pharmaceutical development.

Mechanical-force-induced redox catalysis has emerged as a green and expeditous approach in synthetic chemistry, relying on single-electron transfer from polarized piezoelectric materials to substrates initiated by mechanical agitation. However, the piezoelectric potential generated can sometimes be insufficient to activate the electron transfer process, similar to the limitations observed in photocatalytic reactions. In this work, we introduce a catalytic strategy employing a consecutive mechanical-force-induced electron transfer (ConMET) strategy. This strategy uses piezoelectric materials as mechanochemical redox catalysts with 9-phenyl-dihydroacridine as a sacrificial electron donor, enabling efficient consecutive electron transfer. Our method effectively reduces aryl iodides, bromides, and even electron-rich aryl chlorides, which possess reduction potentials as high as −2.8 V (vs. SCE), leading to the formation of aryl radicals. Ultimately, this strategy facilitates anti-Markovnikov hydroarylation of alkenes and dehalogenative deuteration of aromatic halides under mild conditions.

A photoredox‐catalyzed decarboxylative C( sp ³ )−H alkylation of glycine derivatives, utilizing (+)/(−)‐camphorsultam as a chiral auxiliary and alkyl N ‐hydroxyphthalimide (NHP) ester as a radical precursor, has been developed, providing an efficient approach for the stereoselective synthesis of valuable enantioenriched unnatural α ‐alkylated amino acid derivatives. The methodology operates under mild conditions, demonstrates broad substrate tolerance, and exhibits excellent stereoselectivity. Preliminary mechanistic investigations indicate that the reaction proceeds via a radical pathway.