Iodoalkyne-Based Catalyst-Mediated Activation of Thioamides through Halogen Bonding

Akinobu Matsuzawa; Shiho Takeuchi; Kazuyuki Sugita

doi:10.1002/asia.201601130

Iodoalkyne-Based Catalyst-Mediated Activation of Thioamides through Halogen Bonding

Chem Asian J. 2016 Oct 20;11(20):2863-2866. doi: 10.1002/asia.201601130. Epub 2016 Sep 21.

Authors

Akinobu Matsuzawa¹, Shiho Takeuchi², Kazuyuki Sugita³

Affiliations

¹ Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan. a-matsuzawa@hoshi.ac.jp.
² Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan.
³ Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan. k-sugita@hoshi.ac.jp.

PMID: 27576356
DOI: 10.1002/asia.201601130

Abstract

Halogen bonding catalysis has recently gained increasing attention as a powerful tool to activate organic molecules. However, the variety of the catalyst structure has been quite limited so far. Herein, we report the first example of the use of an iodoalkyne as a halogen bond donor catalyst. By using an iodoalkyne bearing a pentafluorophenyl group as a catalyst, thioamides were efficiently activated and reacted with 2-aminophenol to generate benzoxazoles in good yield. Mechanistic studies, including ¹³ C NMR spectroscopic analysis and several control experiments, provided concrete evidence that this catalytic activation is based on halogen bonding. Thus, the results obtained in this study demonstrate that iodoalkynes can serve as a new scaffold for future development of halogen bonding catalysis.

Keywords: halogen bonds; heterocycles; iodoalkynes; organocatalysis; thioamides.