In the presence of a copper catalyst, a series of oximes undergo deconstructive insertion into coumarins to afford structurally interesting dihydrobenzofuran-fused pyridones in moderate to good yields with good functional group compatibility. The reaction likely involves a radical relay annulation, leading to the ring opening of the lactone moiety of the coumarins, and simultaneous formation of three new bonds. The investigation of photoluminescent properties reveals that several obtained compounds may have potential as fluorescent materials.

The realization of sequential and controllable C–H functionalization in one step can maximize the utilization of C–H bonds to rapidly create valuable scaffolds and dramatically increase the atom and functional group utilization. In this work, we describe an iron-catalyzed relay C–H functionalization proto col that enables de novo synthesis of a wide range of pyridines and pyridones. This transformation involves three-fold C–H functionalization (two Csp3 –H and one Csp2 –H) and allows the simultaneous generation of three chemical bonds and two rings in one step. The reaction features operational simplicity, broad substrate scope (>70 examples), good functional group compatibility, and the suitability to derivation of some bioactive molecules. Various control and kinetic isotope effect experiments were performed to understand the reaction mechanism. DFT investigations support an interesting imine α-carbon radical addition/1,5-hydrogen atom transfer/homolytic aromatic substitution cascade process.

Bridged tetracyclic nitrogen scaffolds are found in numerous biologically active molecules and medicinally relevant structures. Traditional methods usually require tedious reaction steps, and/or the use of structurally specific starting materials....

We describe a synergistic Cu/secondary amine catalysis for skeletal transformation of an oxindole core into a quinolinone skeleton, which generates several structurally new pyridine-fused quinolinones. The synergistic reactions allow expansion of a five-membered lactam ring by radical cation-triggered C–C bond cleavage and enable a further intramolecular cyclization with the aim to construct totally distinct core skeletons.

In the presence of CuOAc, a series of unsymmetric ureas can be generated in moderate to good yields under mild reaction conditions (10 mol% of CuOAc, 2 equiv t-BuONa or PhONa, 30 °C), using aryl isocyanides and O-benzoyl hydroxylamines as the readily accessible starting materials. The reactions might undergo a cascade process involving isocyanide insertion into the N-O bond and Mumm-type rearrangement. This work represents a rare example of isocyanide insertion into N-O bonds, which would extend isocyanide insertion chemistry.