New Arylating Agents in Pd-Catalyzed C–H Bond Functionalization of 5-Membered Ring Heteroarenes

Abstract

In recent years, the palladium-catalyzed direct arylation of heteroaromatics via C-H bond activation has become a popular method for generating carbon-carbon bonds. In most cases, aryl halides were employed as the coupling partners. However, since a few years, several new coupling partners have emerged as useful alternatives for such couplings. This chapter focuses on the recent advances on the discovery of new arylating agents in the palladium-catalyzed arylation of 5-membered ring heteroaromatics.

Regioselectivity in palladium-catalysed direct arylation of 5-membered ring heteroaromatics

“…In the past few years, several new alternative coupling partners have been successfully employed for Pd-catalysed direct arylation of heteroarenes such as ArBIJOH) 2 , ArBF 3 K, ArCO 2 H, ArSiR 3 , ArSO 2 Cl, ArSO 2 Na, ArSO 2 NHNH 2 or even ArH affording a variety of arylated heteroarenes which, in several cases, cannot be obtained using aryl (pseudo)halides as the coupling partners. 57 PdIJ0)/PdIJII) catalytic cycles are certainly involved in most couplings with aryl (pseudo)halides; on the other hand, with some of these new coupling partners such as ArSO 2 Cl, or under oxidative conditions, PdIJII)/PdIJIV) catalytic systems might be involved.…”