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Paper | Regular issue | Vol 100, No. 3, 2020, pp.429-439
Published online, 28th February, 2020
DOI: 10.3987/COM-20-14220
■ Facile Preparation of 2-Oxo-2H-1-pyran-3-carboxylates with the Electron-Withdrawing Group at the 5-Position

Toru Tanaka, Shoki Inoue, Takuya Miura, Yun-Han Hsieh, Hiroki Iwasaki, Minoru Ozeki, Naoto Kojima, and Masayuki Yamashita*

*Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi, Yamashina, Kyoto, Japan

Abstract

A simple and facile procedure for the preparation of 2-oxo-2H-1-pyran-3-carboxylate bearing electron-withdrawing groups, such as the alkylcarbonyl and alkoxycarbonyl moieties, was developed. Various 1,3-dicarbonyl compounds were treated with dimethyl (methoxymethylene)malonate in the presence of Cs2CO3 as a base in tetrahydrofuran at room temperature. This method was particularly effective in the syntheses of bicyclic structures, such as 5,​6,​7,​8-tetrahydro-2,​5-​dioxo-​2H-​1-​benzopyran-​3-​carboxylates.