An article entitled "Transition‐Metal Free Catalytic Synthesis of Trifluoromethyl Indolines by [4+1] Cycloaddition of Trifluoromethyl Benzoxazinones with Sulfur Ylides, Helv. Chim. Acta 2021, 104, e2000217" published by Mr. Koki Kawai (first author, 2nd year doctoral course student) with professor Shibata and others in Helvetica Chimica Acta (Wiley) in 2021 became the most cited article in the two years from 2021 to 2022 (Top Cited Article 2021-2022), and Wiley awarded a certificate (Figure 1). Helvetica Chimica Acta is an international journal founded by the Swiss Chemical Society in 1917 and is one of the oldest international journals in chemistry.

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This article describes an epoch-making technology for synthesizing trifluoromethyl indolines and trifluoromethyl indoles by a very simple method. The compounds are attractive as raw materials for pharmaceuticals, but the number of reports on the synthetic methods was limited. By using this method, trifluoromethyl indolines and trifluoromethyl indoles can be synthesized without using transition metal catalysts, which are frequently used in the synthesis of various compounds but are expensive and may cause adverse effects on the human body. In this article, a novel reaction mechanism was proposed, in which many chemists are thought to have been interested. This method is expected to be applied to more complex and difficult synthesis processes in the future.

Shibata Laboratory

Website containing the published article：Helvetica Chimica Acta

Related article: The research results of the Shibata Laboratory were published on the front cover of ChemistryOpen, "Cover Picture" and "Cover Profile." (Posted on March 18, 2019)