Conghui Xu

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.

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.

Rhodium(I)-catalysed decarbonylative direct C–H vinylation and dienylation of arenes

Rh(I)-Catalyzed decarbonylative direct C–H bond vinylation and dienylation of arenes with readily available acrylic acid and (E)-penta-2,4-dienoic acid under chelation assistance have been developed for the first time. A significant effect of the ligand on the reactivity was observed with the bidentate phosphine ligand being optimal. This protocol was efficient under oxidant-free conditions to access synthetically valuable styrenes and 1-aryl-1,3-butadienes in high yields with a broad substrate scope and good functionality tolerance.