Copper-Catalyzed Intermolecular Dehydrogenative Amidation/Amination of Quinoline <i>N</i>‑Oxides with Lactams/Cyclamines

C–H, N–H dehydrogenative coupling of quinoline <i>N</i>-oxides with lactams/cyclamines has been achieved in the presence of the Cu(OAc)₂ catalyst to give good to excellent yields. This study provides a new strategy for the construction of a 2-aminoquinoline skeleton via direct functionalization of aryl C–H bonds

Access to C4-Functionalized Quinolines via Copper-Catalyzed Tandem Annulation of Alkynyl Imines with Diazo Compounds

An efficient synthesis of C4-functionalized quinolines through copper-catalyzed tandem annulation of alkynyl imines with diazo compounds is described. This transformation involves an <i>in situ</i> formation of allene and intramolecular electrocyclization, which features high efficiency, mild reaction conditions, easy operation, and broad functional-group tolerance. A wide variety of C4-functionalized quinolines were provided in up to 92% yield for 33 examples

Rh(III)-Catalyzed Synthesis of 2‑Alkylbenzimidazoles from Imidamides and <i>N</i>‑Hydroxycarbamates

An efficient tandem reaction of imidamides and <i>N-</i>hydroxycarbamates has been developed. Valuable 2-alkylbenzimidazoles could be easily obtained in up to 97% yield for more than 20 examples. The products would further streamline the synthesis of molecules, which are essential building blocks in organic synthesis and drug discovery. This protocol features high regioselectivity, efficiency, good tolerance of functional groups, and mild reaction conditions

Construction of Fused Polyheterocycles through Sequential [4 + 2] and [3 + 2] Cycloadditions

A method for Pd-catalyzed aerobic oxidative reaction of quinazolinones and alkynes has been developed for sequential [4 + 2] and [3 + 2] cycloadditions to assemble a novel fused-polycyclic system containing tetrahydropyridine and dihydrofuran rings. The reaction process involves C–H and N–H bond functionalization for the formation of tetrahydropyridine and an oxygen radical cyclization for the dihydrofuran ring. This atom- and step-economical synthesis is highly efficient and has good substrate tolerance, which provides a new approach for the construction of polycyclic molecules with potential pharmaceutical interest

Ruthenium-Catalyzed <i>ortho</i>/<i>meta</i>-Selective Dual C–H Bonds Functionalizations of Arenes

The first example of transition-metal-catalyzed <i>ortho</i>/<i>meta</i>-selective dual C–H functionalizations of arenes in one reaction is described. In this transformation, <i>ortho</i>-C–H chlorination and <i>meta</i>-C–H sulfonation of 2-phenoxypyri­(mi)­dines were achieved simultaneously under catalysis by [Ru­(<i>p</i>-cymene)­Cl₂]₂. The other reactant, namely, an arylsulfonyl chloride, played the role of both a sulfonation and chlorination reagent. More importantly, the arylsulfonyl chloride was also an oxidant in the process. Mechanistic studies indicated that six-membered ruthenacycles were the key intermediate in the reaction