The π-extended flavonol Flav-1 (1) undergoes reaction with KOH or KO2 to form 1-, which reacts with O2 at ambient temperature, resulting in CO release and depside formation. Mechanistic and DFT studies support a reaction pathway involving reaction of 1- with O2 on the triplet energy surface in the rate-determining step. Formation of a cyclic peroxide leads to CO extrusion. These studies indicate that if formed in biological environments, 1- will release CO in the absence of light illumination.

Cyclometalated ruthenium(II)-complex-catalyzed selective oxidative scission of olefins to carbonyls is described. A strong C-donor ligand, paired with a rigid backbone and redox activity of ruthenium, provided high catalytic activity and a long lifetime for olefin oxidation. The catalyst tolerates numerous functional groups and applies to challenging biomass-, natural-product-, sugar-, amino-acid-, and fatty-acid-derived substrates.

The asymmetric [5 + 2] cycloaddition of VECs remains to be comparatively rare. Herein, we reported an enantioselective formal [5 + 2] annulation of 3-hydroxyquinolinones and vinylethylene carbonates (VECs) through Pd- and Cu-catalyzed tandem allylation/asymmetric [1,3]-rearrangement/hemiketalization sequences. The strategy exhibits good substrate tolerance, affording a wide range of tricyclic quinolinones bearing two adjacent quaternary stereocenters in moderate to good yields with excellent enantioselectivities.

A KOtBu-promoted [4+2] annulation-dehydration cascade reaction has been developed, enabling the efficient synthesis of diverse 2-pyridone-fused uracils through a vinylogous enolization strategy involving o-quinodimethane (oQDM) dienolate intermediates. This method provides a simple yet robust approach for constructing structurally interesting fused N-heterocycles that incorporate two privileged scaffolds, both of which are widely recognized in drug discovery. Consequently, these compounds hold significant potential for biological and pharmacological applications. Moreover, further transformations of the products obtained from this process allow access to highly functionalized and structurally diverse uracil derivatives, expanding the scope of accessible chemical diversity.

We report herein a visible-light photoredox-catalyzed 1,4-hydrofluoromethylation of terminal-alkene-derived 1,3-enynes with sodium fluoromethylsulfinate, providing an effective protocol to access a diversity of di- and trisubstituted allenes under mild conditions. The synthetic utility of the present protocol was demonstrated by a large-scale reaction as well as the synthetic derivatization of the allene product.

N-directed 2-fold bromoboration reactions of diynes with BBr3 have been developed, allowing the access to novel internally BN-doped polycyclic aromatic hydrocarbons from readily available precursors under mild conditions. Computational investigations identified three potential reaction mechanisms, each involving either BBr3 or [BBr4]-, with low activation barriers (ΔG‡ < 16 kcal/mol) for all pathways. The resulting brominated products can be further functionalized through various cross-coupling protocols, enabling the synthesis of highly luminescent emitters with quantum yield exceeding 90.

A Pd-catalyzed asymmetric Heck cascade reaction involving the intramolecular carbopalladation of unsaturated hydrocarbons, followed by nucleophilic trapping of the resulting palladium species, is a powerful approach for constructing chiral N-heterocycles. However, the use of prochiral nucleophiles in these reactions remains significantly underexplored. Herein, we report a novel Pd/Cu catalytic system for the asymmetric cascade Heck/Tsuji-Trost reaction of allenamides and aldimine esters. This robust method allows for the rapid synthesis of a wide range of enantiopure non-natural α-substituted tryptophans in high yields (up to 99% yield) with excellent enantioselectivities (up to 98% ee). Additionally, the synthetic utility of this protocol is demonstrated through scale-up experiments and diverse valuable transformations.

Sulfur-containing compounds represent a significant category of organic compounds, and the introduction of sulfur groups into organic compounds can effectively enhance their biological activity and synthetic diversity. Although a variety of difunctionalization reactions of alkenes based on sulfur radicals have been documented, significant challenges remain in the carbonylative difunctionalization of unactivated alkenes by the addition of a sulfur radical. Herein, we present a trifluoromethylthiolative carbonylation reaction of unactivated alkenes, which goes through the addition of a trifluoromethylthiol radical to unactivated alkenes and then carbonylation of the newly generated carbon radical intermediate. A heterocyclic/aryl migration in the presence of carbon monoxide is crucial for the success of this methodology and finally resulted in the formation of sulfur-containing carbonylated products in good yields.

4-Amino-5-nitro-7H-pyrazolo[3,4-d][1,2,3]triazine-2-oxide (PTO) is synthesized via one step in this study. Subsequently, 4,7-diamino-5-nitro-pyrazolo[3,4-d][1,2,3]triazine-2-oxide (APTO), 4-oxo-5-nitro-7H-pyrazolo[3,4-d][1,2,3]triazine-2-oxide (OPTO), and several heat-resistant salts are synthesized through local structural modifications on PTO. Comparison of thermal stability between PTO and APTO indicates that while the amino group has a negative impact on the thermal stability of APTO, it enhances the detonation performance of APTO and effectively reduces its mechanical sensitivity. Our findings provide a practical new approach for constructing energetic materials with excellent stability.

A photocatalytic hydroamidomethylation of azobenzenes with N,N-dimethylamides has been developed. Using tetrabutylammonium decatungstate (TBADT) as a photocatalyst, an array of azobenzenes and N,N-dimethylamides reacted smoothly under visible light irradiation, affording previously unreported N-amidomethyl-N,N'-diarylhydrazines in generally high yields. Mechanistic studies indicate that the reaction is enabled by TBADT-mediated hydrogen atom transfer (HAT) photocatalysis. This work is fundamentally different from the previously reported reaction of N,N-dimethylformamide with azobenzenes.