In this article, the structurally well-defined dinuclear complex copper(I) acetate was studied in detail and was developed as a highly practical and efficient catalyst for the copper(I)-catalyzed azide-alkyne cycloaddition. The "bare" phenylethynylcopper(I) (i.e., with no exogeneous ligands) was isolated as an intermediate, which can be converted into an active catalytic species by treatment with acetic acid (in situ produced in the reaction) to efficiently catalyze the azide-alkyne cycloaddition under mild conditions.

A general and efficient procedure for the preparation of phenols was developed by copper-catalyzed oxidative hydroxylation of arylboronic acids at room temperature in water.

In lower nitrile solvents, the N-arylation of azoles with aryl halides was achieved efficiently in the presence of copper powder without any additional ligands. Thus, the first nitrile type of monodentate ligand-mediated, "ligand-free-like" coppercatalyzed N-arylation procedure was established.

S3 Experimental Section General Experimental Methods: IR spectra were recorded as KBr pellets. The 1 H NMR (300 MHz) and 13 C NMR (75 MHz) spectra were recorded in D 2 O or CDCl 3. The J values are given in Hz. MS (EI) spectra were obtained at 70 eV. PE is petroleum ether (60-90 o). N O 8a A Typical Procedure for Preparation of (7aS,11S,13R)-11-Isopropenyl-13phenyl-7a,8,10,11-tetrahydro-9H,13H-naphtho[1,2-e]pyrido[2,1-b][1,3]oxazine (8a): To a cold solution (ice-water bath) of 6 (4.32 g, 10 mmol) in dry THF (70 mL) was added isopropenylmagnesium bromide (0.5 M in THF, 6 mL, 30 mmol) dropwise under nitrogen. After the reaction was stirred at 0 °C for 1.0 h (monitored by TLC), a saturated aqueous solution of NH 4 Cl (30 mL) was added to quench the reaction. Then the resultant mixture was extracted with CH 2 Cl 2 (3 x 30 mL). The combined organic layers were washed with H 2 O and brine and dried over anhydrous Na 2 SO 4. After removal of the solvent, the residue was purified by chromatography (silica gel, EtOAc:PE ＝ 1:15) to give the desired product 8a (3.26 g, 92%) as a colorless crystal, mp 130-131 o C, [α] D

A novel palladium catalyzed direct ortho-arylation of N-phenacylpyridinium bromide was developed. The amazing N-phenacyl group regioselectively activates the C-H bond of pyridine and automatically departs from the arylated products. A kinetic isotope effect study proved that the reaction went through a C-H-bond activation pathway and 2,6-diphenylpyridine was produced stepwise from 2-phenylpyridine.