The direct cross-coupling of quinoline-N-oxides with olefin derivatives has been realized using palladium acetate as the catalyst in the absence of external ligand and oxidant to give the corresponding 2-alkenylated quinolines and 1-alkenylated isoquinolines chemo- and regioselectively in 27−95% yield. The catalytic process is proposed to proceed via direct C−H bond activation of the quinoline-N-oxide with Pd(OAc)2 followed by Heck coupling with the olefin. The resultant N-oxide of the alkenylated quinoline can oxidize the reduced Pd(0) to regenerate the Pd(II) active species and simultaneously release the 2-alkenylated quinoline without using any external oxidants and reductants.

A palladium(II) catalyst promotes condensation of an N-aryl imine and an alkynylbenziodoxolone derivative to afford a multisubstituted furan, whose substituents are derived from the alkynyl moiety (2-position), the imine (3- and 4-positions), and the 2-iodobenzoate moiety (5-position), along with an N-arylformamide under mild conditions. The 2-iodophenyl group of the furan product serves as a versatile handle for further transformations. A series of isotope-labeling experiments shed light on the bond reorganization process in this unusual condensation reaction, which includes cleavage of the C-C triple bond and fragmentation of the carboxylate moiety.

A series of ammonium salt-tagged SIPr-Cu(I) complexes have been conveniently synthesized and characterized by NMR and HRMS. They are highly active toward the three component click reaction of benzyl bromide, NaN 3 and alkyne with water as solvent at rt. Current water soluble NHC-Cu(I) catalyst could be efficiently used at least four times with an 84% isolated yield of the desired triazole in the last run.

Alkynyl-λ(3)-iodanes have been established as alkynyl cation equivalents for the alkynylation of carbon- and heteroatom-based nucleophiles. Herein, we report an unprecedented reaction mode of this compound class, which features a Pd(II)-assisted 1,2-I(III) shift of an alkynylbenziodoxole. A Pd(II) catalyst mediates this shift and the subsequent interception of the transient vinylidene species with carboxylic acid (1,1-hydrocarboxylation). The product of this stereoselective rearrangement-addition reaction, β-oxyalkenylbenziodoxole, represents a novel and useful building block for further synthetic transformations.

The direct ring construction of amides with alkynes catalyzed by palladium acetate with cheap oxidant under an air atmosphere has been realized. A variety of novel highly substituted naphthalenes 3a-3l have been prepared chemo- and regioselectively in 55-97% yields under mild conditions. Product 3j emits intense blue luminescence peaked at 435 nm with a good blue purity.