Dual-Functionalization of Alkynes via Copper-Catalyzed Carbene/Alkyne Metathesis: A Direct Access to the 4‑Carboxyl Quinolines

A copper-catalyzed novel carbene/alkyne metathesis cascade reaction with alkyne-tethered diazo compounds is described. The whole transformation features a dual-functionalization of alkyne to install one CN and one CC bond on each carbon with azide and diazo groups, respectively, in one reaction, which represents a practical synthetic alternative to the multisubstituted 4-carboxyl quinoline derivatives and with most of them in high to excellent yields

Dual-Functionalization of Alkynes via Copper-Catalyzed Carbene/Alkyne Metathesis: A Direct Access to the 4‑Carboxyl Quinolines

A copper-catalyzed novel carbene/alkyne metathesis cascade reaction with alkyne-tethered diazo compounds is described. The whole transformation features a dual-functionalization of alkyne to install one CN and one CC bond on each carbon with azide and diazo groups, respectively, in one reaction, which represents a practical synthetic alternative to the multisubstituted 4-carboxyl quinoline derivatives and with most of them in high to excellent yields

1,3-Dipolar Cycloaddition of Alkyne-Tethered <i>N</i>‑Tosylhydrazones: Synthesis of Fused Polycyclic Pyrazoles

A general and transition-metal-free access to the fused polycyclic pyrazoles via an intramolecular 1,3-dipolar cycloaddition reaction of alkyne-tethered tosylhydrazones has been reported. The pure solid products could be obtained without column chromatography in high to excellent yields, and the obtained products are useful bioactive molecules or could be used as the key intermediate for synthesis of these compounds in one or two steps. Additionally, a [3+2]-cycloaddition followed by a direct <i>H</i>-shift aromatization reaction mechanism was proposed, which is different from the previously reported aryl or alkyl sequential [1,5]-sigmatropic rearrangement pathway