An efficient route to regioselective functionalization of benzo[b]thiophenes via palladium-catalyzed decarboxylative Heck coupling reactions: insights from experiment and computation was written by Yang, Daoshan;Liu, Yuxia;Sun, Pengfei;Zhang, Ning;Wei, Wei;Sun, Mingyang;Chen, Guang;Bi, Siwei;Wang, Hua. And the article was included in Organic & Biomolecular Chemistry in 2016.Formula: C10H4ClF3O2S This article mentions the following:
Pd-catalyzed decarboxylative Heck-type coupling of 3-chlorobenzo[b]thiophene-2-carboxylic acids with styrenes have been developed as an efficient strategy for the construction of functionalized benzo[b]thiophenes I (R1 = H, 6-Me, 6-Cl, 6-Br, 6-CF3, 6-NO2, 6-OMe; R2 = H, 4-Me, 3-Me, 4-Cl, etc.; R3 = Cl, Br, H). Theor. anal. shows that AgCl generated during the reaction, instead of Pd, π-coordinates with the carboxyl O atom, making easy the rate-determining CO2 dissociation The divergent reactivities of the Cl-substituted and H-substituted 3-benzo[b]thiophene-2-carboxylic acids are mainly due to the presence of the Cl substituent, which reduces the adjacent π-π interplay, thereby significantly contributing to decarboxylation. Therefore, the presence of both AgCl and the Cl substituent are of key importance in ensuring the occurrence of the reaction under the given conditions. In the experiment, the researchers used many compounds, for example, 3-Chloro-6-(trifluoromethyl)benzo[b]thiophene-2-carboxylic acid (cas: 923849-73-4Formula: C10H4ClF3O2S).
3-Chloro-6-(trifluoromethyl)benzo[b]thiophene-2-carboxylic acid (cas: 923849-73-4) belongs to benzothiophene derivatives. Benzothiophene is used as starting material for the synthesis of bioactive molecules. The core structure is a part of various pharmaceutical substances and natural products. It is also used in the manufacturing of dyes such as thioindigo.Formula: C10H4ClF3O2S
Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem