Volume 62, Issue 29 e202305480
Communication

Enantioselective Synthesis of 1,2-Benzothiazine 1-Imines via RuII/Chiral Carboxylic Acid-Catalyzed C−H Alkylation/Cyclization

Long-Tao Huang

Long-Tao Huang

Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo, 060-0812 Japan

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Yuta Kitakawa

Yuta Kitakawa

Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo, 060-0812 Japan

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Kodai Yamada

Kodai Yamada

Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo, 060-0812 Japan

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Futa Kamiyama

Futa Kamiyama

Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo, 060-0812 Japan

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Dr. Masahiro Kojima

Dr. Masahiro Kojima

Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo, 060-0812 Japan

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Dr. Tatsuhiko Yoshino

Corresponding Author

Dr. Tatsuhiko Yoshino

Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo, 060-0812 Japan

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Prof. Dr. Shigeki Matsunaga

Corresponding Author

Prof. Dr. Shigeki Matsunaga

Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo, 060-0812 Japan

Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502 Japan

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First published: 17 May 2023
Citations: 12

Graphical Abstract

Enantioselective C−H alkylation/cyclization of sulfondiimines with sulfoxonium ylides using a RuII catalyst and a newly developed chiral spiro carboxylic acid enables the synthesis of 1,2-benzothiazine 1-imines, thus expanding the accessible chemical space of chiral hexavalent organosulfur scaffolds relevant to biologically active compounds.

Abstract

Sulfondiimines are diaza-analogues of sulfones with a chiral sulfur center. Compared to sulfones and sulfoximines, their synthesis and transformations have so far been studied to a lesser extent. Here, we report the enantioselective synthesis of 1,2-benzothiazine 1-imines, i.e., cyclic sulfondiimine derivatives from sulfondiimines and sulfoxonium ylides via C−H alkylation/cyclization reactions. The combination of [Ru(p-cymene)Cl2]2 and a newly developed chiral spiro carboxylic acid is key to achieving high enantioselectivity.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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