Rhodium‐Catalyzed meta‐C−H Functionalization of Arenes

Abstract

Rhodium-catalyzed ortho-C-H functionalization is well known in the literature. Described herein is the Xphos-supported rhodium catalysis of meta-C-H olefination of benzylsulfonic acid and phenyl acetic acid frameworks with the assistance of a para-methoxy-substituted cyano phenol as the directing group. Complete mono-selectivity is observed for both scaffolds. A wide range of olefins and functional groups attached to arene are tolerated in this protocol.

Accessing Remote meta‐ and para‐C(sp2)−H Bonds with Covalently Attached Directing Groups

“…[31] phenethyl sulfonate (R = H) meta-olefination [32] aryl alcohol and acid (R = OMe) meta-olefination [33] aryl sulfonates (R = OMe) meta-silylation meta-germanylation [34] benzylsulfonyl esters phenylacetic acids meta-olefination [36] benzyl sulfonyl esters meta-olefination [41] benzyl sulfonates meta-cyanation meta-alkylation [43] [44] aryl sulfonates meta-cyanation meta-alkylation meta-alkenylation [43] [44] [44] phosphonate benzyl phosphonates meta-olefination meta-acetoxylation meta-hydroxylation [37] Angewandte Chemie Reviews…”

“…Thep otential of this procedure was demonstrated by sequential ortho-and meta-olefination of phenethylamine derivatives (31)(32)(33)(34)(35)(36). Finally,the directing group was removed under acid hydrolysis to afford meta-substituted phenylethylamine 37.…”

Palladium‐Catalyzed meta‐Selective C‐H Alkenylation and Acetoxylation of Arylacetic Acid Using a Pyrimidine Template

“…On the other hand, the introduction of alkenyl group to an aryl C‐H bond is also attractive because alkene moiety can be further converted into a wide range of functional groups . However, to the best of our knowledge, there are only a few examples regarding the meta ‐C‐H activation of phenylacetic acid derivatives, which were reported by Yu and Maiti using a U‐shaped directing template under palladium(II) catalysis . Inspired by the above results, we reasoned that the relatively strong coordinating pyrimidine template should be superior and may also broaden the scope of substrates.…”

“…( E )‐3‐(3‐(Carboxymethyl)‐5‐methylphenyl)acrylic Acid (5e): [11d] White solid; yield: 17.7 mg (81 %); 1 H NMR (400 MHz, [D 6 ]DMSO) δ 12.57 (s, 2H), 7.51 (d, J = 16.0 Hz, 1H), 7.38 (s, 1H), 7.35 (s, 1H), 7.12 (s, 1H), 6.47 (d, J = 16.0 Hz, 1H), 3.55 (s, 2H), 2.30 (s, 3H). 13 C NMR (100 MHz, [D 6 ]DMSO) δ 173.1, 168.1, 144.3, 138.5, 136.2, 134.6, 132.5, 127.5, 126.9, 119.6, 40.8, 21.2.…”

Carboxy Group as a Remote and Selective Chelating Group for C−H Activation of Arenes

“…To examine our hypothesis, we synthesized the hydrocinnamic amide 1 a H as the substrate and chose olefination as the model reaction (Table ). After screening a series of reaction conditions, we were very glad to obtain 18 % yield of remote selective, meta ‐olefinated products using Pd(OAc) 2 in HFIP (hexafluoroisopropanol) at 80 °C for 24 h (entry 1) . Notably, only traces of olefination products at the o 1 ‐ and p ‐positions of the target phenyl ring were obtained ( m : o 1 =91:9 and m : p= 95:5, see the Supporting Information for the synthesis of the isomers).…”