Palladium-Catalyzed Decarboxylative ortho-Acylation of Benzamides with α-Oxocarboxylic Acids

Abstract

A palladium-catalyzed decarboxylative ortho-acylation of tertiary benzamides with α-oxocarboxylic acids by weak O-coordination has been described. This reaction proceeds smoothly with a high monoacylation selectivity, affording ortho-acylated benzamides in moderate to good yields. When secondary benzamides are employed as the substrates, the formed ortho-acylated benzamides undergo further intramolecular cyclization to provide isoindolinone derivatives. In addition, several transformations of the synthesized ortho-acylated benzamides into a diversity of synthetically valuable products have been demonstrated.

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

“…Again Pd(OAc) 2 is used as catalyst in presence of an oxidant, in this case K 2 S 2 O 8 (not shown). 225 …”

C–H Functionalization of Aromatic Amides

“…Recently, Wang's team reported a Pd‐catalyzed ortho ‐C–H activation/cross‐coupling reaction of tertiary benzamides with α‐oxocarboxylic acids to achieve the ortho ‐acylation of aromatic amides using tertiary amide as directing group (Scheme ) . The method provides moderate to good yields, and exhibits excellent regioselectivity and functional group tolerance.…”

Pd(II)-Catalyzed C-H Acylation of (Hetero)arenes—Recent Advances

“…Besides, the weak coordination of the amide and the electron deficient aryl ring makes them difficult substrates for palladium catalyzed C-H activation. Despite this, two examples of decarboxylative acylation of benzamides 22 with α-oxocarboxylic acids 8 were described almost simultaneously ( Scheme 7 ) [ 25 , 26 ]. In both cases, dialkyl or cyclic amides could be used as directing groups.…”