By making use of a dual-chelation-assisted strategy, a completely regiocontrolled oxidative C-H/C-H cross-coupling reaction between an N-acylaniline and a benzamide has been accomplished for the first time. This process constitutes a step-economic and highly efficient pathway to 2-amino-2'-carboxybiaryl scaffolds from readily available substrates. A Cp*-free RhCl /TFA catalytic system was developed to replace the [Cp*RhCl ] /AgSbF system generally used in oxidative C-H/C-H cross-coupling reactions between two (hetero)arenes (Cp*=pentamethylcyclopentadienyl, TFA=trifluoroacetic acid). The RhCl /TFA system avoids the use of the expensive Cp* ligand and AgSbF . As an illustrative example, the procedure developed herein greatly streamlines the total synthesis of the naturally occurring benzo[c]phenanthridine alkaloid oxynitidine, which was accomplished in excellent overall yield.

A highly efficient and selective Ru-catalyzed direct C2-olefination of indoles, pyrroles, and carbazoles assisted by a removable N-dimethylcarbamoyl group has been developed by using O2 as the terminal oxidant. Both electron-deficient and unactivated alkenes are applicable to the protocol.

Herein we disclose the first example of transition-metal-catalyzed oxidative coupling/annulation of simple benzoic acids with terminal alkynes via C–H activation. A range of aromatic carboxylic acids and terminal alkynes have been found to be viable substrates in this reaction, providing a simple and efficient method for the synthesis of diverse 3-ylidenephthalides with complete Z selectivity.

β-Azolyl propanoic acid derivatives are frequently found in biologically active molecules and pharmaceuticals. Here, we report the oxidative heteroarylation of unactivated C(sp)-H bonds with azole C(sp)-H bonds via copper or nickel catalysis with the aid of removable bidentate auxiliary, which provides a rapid pathway to β-azolyl propanoic acid derivatives. A variety of azoles such as oxazole, benzoxazole, thiazole, benzothiazoles, benzimidazole, purine, and even [1,2,4]triazolo[1,5-a]pyrimidine could be engaged in this protocol.

Two efficient ruthenium sensitizers with a phenothiazine-modified bipyridine as an ancillary ligand, coded SCZ-1 and SCZ-2, have been developed as dyes in dye-sensitized solar cells (DSSCs). Both sensitizers exhibit low-energy metal-to-ligand charge transfer (MLCT) bands centered at 539 nm with high molar extinction coefficients of 1.77 × 10(4) M(-1) cm(-1) for SCZ-1 and 1.66 × 10(4) M(-1) cm(-1) for SCZ-2, which are significantly higher than the corresponding value for the reference N719 (1.27 × 10(4) M(-1) cm(-1)), indicating that the light-harvesting capacity of ruthenium sensitizers can be reinforced by introducing phenothiazine moieties into the bipyridine ligand. Under AM 1.5G irradiation (100 mW cm(-2)), SCZ-1 and SCZ-2 sensitized DSSC devices show impressive power conversion efficiencies (PCE) up to 10.4% by using of iodide-based electrolytes, which exceeds that of N719 (9.9%) under the same conditions. Both of the open circuit voltage (VOC) and fill factor (FF) of SCZ-sensitized solar cells approximate to those of N719-sensitized cell. The relatively higher efficiencies of the SCZ-sensitized cells than that of N719-sensitized cell come from their higher short-circuit photocurrent density (JSC), which may be mainly attributed to the high absorption coefficient. The absorption spectrum and device efficiency of SCZ-1 are both quite close to those of SCZ-2, suggesting that the difference in alkyl chains on the N atom of phenothiazine is not a decisive factor in affecting the photovoltaic performance of dyes.