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One-Pot Synthesis of 2-Sulfonamidobenzo[b]thiophenes Enabled by a Mild Protonative Activation of Ynamides

Solbin Kim, So Yeun Lim, Kihun Kwak, Hee Nam Lim*, Hyun-Suk Yeom*

*Yeungnam University, 280 Daehak-Ro, Gyeongsan, Gyeongbuk, 38541; KRICT, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea, Email:,

S. Kim, S. Y. Lim, K. Kwak, H. N. Lim, H.-S. Yeom, Synthesis, 2022, 54, 5451-5460.

DOI: 10.1055/a-1929-2650

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Silica gel promotes a protonative intramolecular cyclization of ynamides containing an o-(methylthio)aryl group to provide functionalized 2-amidobenzo[b]thiophenes in good yields. Compared with ynamide activation methods that use strong Brønsted acids or expensive transition metals, this protocol is mild and economical.

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Key Words

ynamides, one pot, electrophilic cyclization, benzothiophenes, silica gel assisted

ID: J66-Y2022