Pd-Catalyzed Decarboxylative Ortho-Halogenation of Aryl Carboxylic Acids with Sodium Halide NaX Using Carboxyl as a Traceless Directing Group

Abstract

A highly regioselective Pd-catalyzed carboxyl directed decarboxylative ortho-C–H halogenation of cheap o-nitrobenzoic acids with NaX (X = I, Br) under aerobic conditions has been established. The utility of the method has been demonstrated by the gram-scale reaction and derivatization of the product. Experimental results have confirmed Pd and Bi played critical roles in the transformation and indicated the transformation might proceed via 2-halo-6-nitrobenzoic acid derivative intermediate.

Ipso Nitration of Aryl Boronic Acids Using Fuming Nitric Acid

“…1 H NMR (400 MHz, CDCl 3 ): δ 8.19 (br s, 1H), 7.99 (br s, 1H), 7.67 (br s, 1H), 2.47 (s, 3H). Spectral data are in agreement with the literature …”

ortho-C—H Bond Functionalization of Carboxylic Acid Using Carboxyl as a Traceless Directing Group Based on the Strategy of “Two Birds with One Stone”

“…此外, 韩福忠等 [61] 蔡琥课题组 [63] 在氧气条件下以 Bi(NO 3 ) 3 •5H 2 O 为添 加剂, 实现了羧基无痕导向 Pd/Cu 催化邻硝基苯甲酸类 化合物 C-6 位 C-H 键活化与 NaX (X＝I, Br)生成碳-卤 键的反应(Eq. 6).…”

Ag/Cu-Mediated Decarboxylative Cyanation of Arene Carboxylic Acids Using NH4+/N,N-Dimethylformamide as Combined Cyanide Source

“…[2] In recent decade, reliable methods of transition metal-catalyzed decarboxylative functionlization transformations to create alkenes, [3] alkynes, [4] azides, [5] amines, [6] biaryls, [7] halides, [8] trifluoromethyl(thio) compounds [9] and other functional compounds [10] have been well established. In view of our continuing research pursuit in functionalization transformation of carboxylic acids, we have made great progress in Pd-mediated decarboxylative orthohalogenation of aromatic carboxylic acids using carboxyl as traceless directing group, [11] K 2 CO 3 mediated coupling of carboxylic acids with CH 2 Cl 2 as methylene synthon, [12] and Cu-promoted decarboxylative ipso-functionalization of aryl carboxylic acids including decarboxylative methylthiolation, [13] arylation, [14] protonation, [15] halogenation and cyanation. [16] As core structural motifs, aryl nitriles are of great importance to many value-added pharmaceuticals, agrochemicals, dyes and materials, in addition, aryl nitriles can serve as versatile synthetic platforms to produce a wide variety of functional groups including amines, amides, aldehydes, tetrazoles and others.…”