Lingjuan Zhang

Rhodium-Catalyzed Decarbonylative Direct C2-Arylation of Indoles with Aryl Carboxylic Acids

A RhI‐catalyzed direct C2‐arylation of indoles with diversely substituted aryl carboxylic acids has been developed using 2‐pyrimidyl group as an easily installable and readily removable N‐directing group. The reaction proceeded smoothly without the need for any external oxidants under relatively mild conditions to produce the C2‐arylated indoles in high yields with excellent regioselectivity. A range of functional groups in both coupling partners were tolerated regardless of their electronic properties and positions. With the assistance of the 2‐pyrimidyl group, these C2‐functionalized products could further undergo C7‐arylation to give the C7‐aryl indole products. Mechanistic evidence supports that the reaction involves a decarbonylation step, and the carboxylic acids could be activated in situ by treatment with (tBuCO)2O to generate the active anhydrides.

Direct synthesis of 8-aryl tetrahydroquinolines via pd-catalyzed ortho-arylation of aryl ureas in water

An efficient protocol for the direct synthesis of 8-arylated tetrahydroquinolines via Pd-catalyzed ortho-arylation of aryl ureas with aryl iodides was developed. The reaction proceeded smoothly in water under ligand-free and surfactant-free conditions, providing the desired products in high yields with remarkable functional group tolerance.

Palladium‐Catalyzed Direct Arylation of Allylamines with Simple Arenes

The Pd(OAc)2‐catalyzed direct CH bond olefination of unreactive arenes with allylamines in the presence of AgOAc was developed. A variety of allylamines including β‐substituted substrates underwent smooth coupling reactions with various arenes to give exclusively the terminal arylation products in high yields with excellent regioselectivities and stereoselectivities. The reaction is compatible with a range of functional groups in both coupling partners. The carbonyl group in the allylamine substrates is critical to catalysis, and the high regio‐ and stereocontrol observed is attributed to coordination between the carbonyl O and Pd atoms.

Pd-catalyzed ligand-free Suzuki reaction of β-substituted allylic halides with arylboronic acids in water

The catalyst system consisting of Pd(TFA)2 and KOH allows for a wide range of β-substituted allylic halides to react efficiently with various arylboronic acids in neat water under ligand-free conditions, affording the allylated arenes in high yields with broad functional group tolerance and up to 7.4 × 105 TON and 15416 h−1 TOF.