Direct Carboxylation of Electron-Rich Heteroarenes Promoted by LiO-tBu with CsF and [18]Crown-6 was written by Shigeno, Masanori;Hanasaka, Kazuya;Sasaki, Keita;Nozawa-Kumada, Kanako;Kondo, Yoshinori. And the article was included in Chemistry – A European Journal in 2019.Electric Literature of C10H7BrO2S This article mentions the following:
The combination of LiO-tBu, CsF, and [18]crown-6 efficiently promoting the direct C-H carboxylation of electron-rich heteroarenes (benzothiophene, thiophene, benzofuran, and furan derivatives) I (R = Me, CN, Br, MeO, Cl, F; R1 = H, CH3, Br) and II (R2 = Br, C6H5, C(O)C6H5, etc.; R3 = H; R2R3 = CH=CH-CH=CH; X = O, S) has been demonstrated. A variety of functional groups, including Me, methoxy, halo, cyano, amide, and keto moieties, is compatible with this system. The reaction proceeds via the formation of a tert-Bu carbonate species. In the experiment, the researchers used many compounds, for example, Methyl 5-bromobenzo[b]thiophene-2-carboxylate (cas: 7312-11-0Electric Literature of C10H7BrO2S).
Methyl 5-bromobenzo[b]thiophene-2-carboxylate (cas: 7312-11-0) belongs to benzothiophene derivatives. Benzothiophenes are valuable heterocycles that are widely used in medicines, agrochemicals, and materials science. The different substitution patterns in these heterocycles offer new opportunities for drug discovery and other applications in materials science.Electric Literature of C10H7BrO2S
Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem