Hai-Tao Zhu

A K₂S₂O₈-mediated tandem bromination/Truce–Smiles rearrangement/desulfonylation of N-arylsulfonyl acrylamides with sodium bromide has been developed. This reaction exhibits broad functional group compatibility and scalability, delivering structurally diverse β-brominated amides containing a quaternary carbon center in good yields. Mechanistic studies indicated that the formation of bromine radicals represents the crucial step in this radical cascade transformation. This approach provides a complementary and efficient route toward the synthesis of valuable β-brominated amide derivatives.

This review highlights the latest advancements in the meta -C–H functionalization of pyridines through a temporary dearomatization strategy involving dihydropyridine, oxazino-pyridine, Zincke imine and radical ion dearomatized intermediates.

A Brønsted acid-catalyzed three-component modular phosphonylation/cyclization protocol has been established for the efficient synthesis of phosphinylated 2H-isoindoles, employing o-propargyl alcohol benzaldehydes, diarylphosphine oxides, and arylamines as starting materials. This metal-free cascade transformation is characterized by mild conditions, broad substrate compatibility, gram-scale synthesis, and one-pot construction of C–P, C–N, and CC bonds. Mechanistic studies revealed that this chemistry involves Kabachnik–Fields reaction, 5-exo-dig cyclization, and aromatization. Interestingly, these isoindole-substituted phosphine oxides emit bright fluorescence in the aggregated states under UV irradiation.

A visible-light-enabled fluorosulfonylalkynylation of alkenes has been developed using alkynyl sulfonyl fluorides as bifunctional reagents under catalytic aryl diazonium activation. This photocatalyst- and oxidant-free protocol affords diverse 1-sulfonyl fluoride-2-alkynyl adducts in good yields with excellent chemoselectivity and a broad scope, enabling late-stage diversification while installing a SuFEx-ready sulfonyl fluoride and a versatile alkyne in one step.

A photocatalytic alkylation of heterocycles using recyclable Cu@g-C ₃ N ₄ photocatalysts under additive-free conditions was described, featuring high efficiency and a broad substrate scope and enabling heterogeneous catalyst reuse for five cycles.

Herein, we report a practical semiheterogeneous strategy for the photosynthesis of diverse selanyl phenanthrenes, employing CoS₂ as a heterogeneous photocatalyst in combination with ferrocene (Cp₂Fe) as a homogeneous redox catalyst. This synergistic system combines photogenerated electron-mediated reduction of selenyl cations into diselenide with photogenerated hole oxidation of Cp₂Fe to its oxidized form, which not only oxidizes diselenide into selenyl radicals but also mediates oxidative dehydroaromatization, leading to high-yielding transformations with broad functional group compatibility. Notably, this method eliminates the need for stoichiometric oxidants or reductants and avoids sacrificial electron donors or acceptors.

A highly efficient method for the straightforward synthesis of skipped 1,4-dienes is presented via p-TsOH·H₂O-catalyzed intramolecular intercepted Meyer–Schuster rearrangement/allylic alkenylation of propynolaldehydes with olefins in a one-pot manner. This cascade transformation is characterized by metal-free and mild conditions, extensive substrate applicability, atom economy, gram-scale production, and water as the sole by-product. Furthermore, the resulting functionalized 1,4-dienes could be derivatized by Fe(III)-promoted radical cyclization, allylic methoxylation under reductive conditions, and Pd(II)-catalyzed Sonogashira coupling.