A direct oxidative cross-coupling between terminal alkynes and secondary phosphine oxides was developed. This approach provides an efficient way to construct alkynyl di(phenyl) phosphine oxides from basic materials, and in this process, the silver salts act as a key promoter.

An external oxidant-free C-H functionalization/C-O bond formation reaction for constructing benzo-3,4-coumarins accompanied by quantitative H evolution has been developed. High functional group tolerance and excellent reaction efficiency are shown in this transformation. Meanwhile, the substrates containing heterocyclic substituents such as thienyl-, pyridinyl-, and pyrrolylbenzoic acids displayed good performance. Importantly, this reaction can be performed with good efficiency on a gram scale. A cyclic voltammetry study and density functional theory calculations could provide insight into the mechanism of this reaction.

Silver-mediated isocyanide-alkyne [3 + 2] cycloaddition has been developed as a new method for the synthesis of pyrroles. Density functional theory (DFT) calculations toward this reaction reveal that terminal alkynes participated cycloadditions proceed through two successive 1,5-silver migrations, in which the silver migrates between two carbon atoms and finally returns to original carbon. Natural population analysis (NPA) indicates that silver migration guides the move of charge into a rational way, thereby facilitating the cycloaddition. An analogous silver-migration mechanism is also suitable to explain the reactivity of the cycloaddition between isocyanide and internal alkynes, which shows the generality of the silver-migration process. Moreover, competitive experiments are consistent with the computational results, which provides further support for the mechanism.

COMMUNICATION This journal isAn environmental friendly direct oxidative amidation between methylarenes and free amines was developed. The aromatic amide could be prepared efficiently from raw chemicals by employing TBHP as the "green" oxidant with the co-catalysis of TBAI and FeCl 3 in water.