CuI-Catalyzed Coupling Reactions of 4-Iodopyrazoles and Alcohols: Application toward Withasomnine and Homologs

• Published in: Molecules (Basel, Switzerland) Vol. 26; no. 11; p. 3370
• Main Authors: Usami, Yoshihide, Kubo, Yumika, Takagaki, Toshiki, Kuroiwa, Nao, Ono, Jun, Nishikawa, Kohei, Nakamizu, Ayaka, Tatsui, Yuya, Harusawa, Shinya, Hayama, Noboru, Yoneyama, Hiroki
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02-06-2021; MDPI
• Subjects: 4-alkoxypyrazole; Alcohol; Alcohols; Chemical reactions; coupling reaction; CuI; Cytochrome; Dehydrogenases; Homology; Hydrogenation; Irradiation; Ligands; microwave; Potassium; Pyrazoles; Solvents; synthesis; withasomnine; synthesis; coupling reaction; CuI; withasomnine; homologue; microwave; 4-alkoxypyrazole
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26113370

The direct 4-alkoxylation of 4-iodo-1
-pyrazoles with alcohols was achieved by a CuI-catalyzed coupling protocol. The optimal reaction conditions employed excess alcohol and potassium
-butoxide (2 equiv) in the presence of CuI (20 mol%) and 3,4,7,8-tetramethyl-1,10-phenanthroline (20 mol%) at 130 °C for 1 h under microwave irradiation. The present method was efficiently applied to the synthesis of withasomnine and its six- and seven-membered cyclic homologs.